8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 18, 2009

Maxygen, Inc.

(Exact name of registrant as specified in its charter)

Delaware	000-28401	77-0449487
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

515 Galveston Drive

Redwood City, CA 94063

(Address of principal executive offices)

(650) 298-5300

(Registrant’s telephone number, including area code)

Not Applicable.

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.01 Entry into a Material Definitive Agreement.

On September 18, 2009, Maxygen, Inc. (the “Company”) consummated the transactions (the “Transactions”) contemplated by the Master Joint Venture Agreement (the “Joint Venture Agreement”) dated as of June 30, 2009 by and among the Company, Astellas Pharma Inc. (“Astellas”) and Astellas Bio Inc. (“Bio”) (the consummation of such transactions, the “Closing”). Pursuant to the Joint Venture Agreement, the Company established a joint venture subsidiary, Perseid Therapeutics LLC, a Delaware limited liability company (“Perseid”), focused on the discovery, research and development of multiple protein pharmaceutical programs, including the Company’s MAXY-4 program and other early stage programs.

In connection with the Closing, the Company entered into an Asset Contribution Agreement (the “Asset Contribution Agreement”) with Perseid, pursuant to which the Company contributed substantially all of its programs and technology assets in protein pharmaceuticals, in exchange for an ownership interest in Perseid. The Company and Bio also entered into a Series A and Series B Preferred Unit Purchase Agreement with Perseid, pursuant to which Perseid issued preferred units to each of the Company and Bio. Perseid issued to the Company 10,000,000 Series A Preferred Units at a purchase price of $1.00 per unit for an aggregate purchase price of $10,000,000, and 40,000,000 Series A Preferred Units in exchange for certain contributed assets pursuant to the Asset Contribution Agreement. Perseid issued to Bio 10,000,000 Series B Preferred Units at a purchase price of $1.00 per unit for an aggregate purchase price of $10,000,000. The preferred units were issued pursuant to an exemption from the registration requirements of the Securities Act of 1933, as amended, contained in Section 4(2) of such Act.

Pursuant to an Investors’ Rights Agreement by and among the Company, Astellas, Bio, and Perseid, Astellas was granted an option to acquire all of the Company ownership interest in Perseid at specified exercise prices that will increase each three-month period from $53 million to $123 million over the term of the option, which expires on the third anniversary of the Closing.

In addition to the Investors’ Rights Agreement, the Company also entered into Perseid’s Limited Liability Company Agreement as a member, a Co-Sale Agreement and a Voting Agreement, which agreements govern the relationship of the Company and Bio as investors in Perseid.

Also at the Closing, the Company entered into a Technology License Agreement with Perseid under which the Company granted Perseid certain exclusive licenses to use the Company’s MolecularBreeding™ technology platform and ancillary protein expression technologies for the discovery, research and development of protein pharmaceuticals, subject to certain existing licenses and other limitations.

All the agreements referenced above, as well as other material terms of the Joint Venture Agreement and the transactions contemplated thereby, are further described in the Company’s Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

The foregoing description of the Transactions does not purport to be complete and is qualified in its entirety by reference to the Joint Venture Agreement, a copy of which is attached as Exhibit 2.1 to the Current Report on Form 8-K filed on July 1, 2009 and is incorporated herein by reference, and the agreements contemplated thereunder, copies of which are attached as exhibits to this Current Report on Form 8-K and are incorporated herein by reference.

In addition, a copy of the press release issued by the Company regarding the Closing of the Transactions is also attached as an exhibit to this Current Report on Form 8-K and is incorporated herein by reference.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(b)

In connection with the Closing of the Transactions on September 18, 2009, Grant Yonehiro’s position as chief business officer of the Company terminated. As previously disclosed and as described below, Mr. Yonehiro will serve as Chief Executive Officer and President of Perseid.

(e)

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Compensation Arrangements with Executive Officers

Upon the Closing, the previously executed Amended and Restated Change in Control Agreements between the Company and each of Russell Howard, the Company’s chief executive officer, Elliot Goldstein, the Company’s chief operating officer, and Lawrence Briscoe, the Company’s chief financial officer, became effective. The Amended Change in Control Agreements amend the prior agreements between the Company and each officer to provide, among other things, that the Closing will constitute a “change of control” under such agreements, entitling the officers to certain payments and benefits as provided under the terms of the agreements, as amended.

Upon the Closing, the previously executed Retention Agreement and Amended and Restated Change in Control Agreement between the Company and Grant Yonehiro, the Company’s chief business officer, became effective. The Retention Agreement provides, among other things, for a transaction bonus payment to Mr. Yonehiro of $600,000 following the Closing and additional cash retention payments of $200,000 on each of the first three anniversary dates of the Closing, subject to Mr. Yonehiro’s continued employment with the Company or Perseid. The Restated Change in Control Agreement provides that such agreement will terminate on December 31, 2009 if no “change of control” has occurred with respect to the Company.

Upon the Closing, an employment offer letter agreement, previously executed by Mr. Yonehiro and the Company, acting on behalf of Perseid, became effective. Pursuant to the terms and conditions of the offer letter, Mr. Yonehiro will serve as Chief Executive Officer and President of Perseid, effective as of the Closing Date.

All the agreements referenced above are further described in the Company’s Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009. The foregoing description of the Amended and Restated Change in Control Agreements with each of the officers, the Retention Agreement and the employment offer letter does not purport to be complete and is qualified in its entirety by reference to the copies of these agreements attached as exhibits to the Current Report on Form 8-K filed on July 1, 2009, each of which is incorporated herein by reference.

Perseid Equity Incentive Plan

Perseid has adopted the 2009 Equity Incentive Plan (the “Equity Incentive Plan”), pursuant to which equity awards may be granted to employees and other eligible service providers of Perseid or any parent or subsidiary thereof. The Equity Incentive Plan provides for the grant of Common Units of Perseid as LLC profits interest units. A total of 15,000,000 Common Units are reserved for issuance under the Equity Incentive Plan, subject to adjustment in the event of certain changes in the capitalization of Perseid affecting Common Units. The Equity Incentive Plan will be administered by the Board of Managers of Perseid or a designated committee thereof, which will have discretion to select service providers who will receive awards, the terms and conditions of such awards (consistent with the terms of the plan), and to make all other determinations necessary or advisable in administering the Equity Incentive Plan. Perseid has also adopted a form of profits interest unit agreement for use under the Equity Incentive Plan. Grants of LLC profits interest units will generally vest as determined by the Administrator and require the participant to continue as a service provider through the relevant vesting date(s). LLC profits interest units that have not vested upon the participant’s termination of service generally will be forfeited at no cost to Perseid.

In connection with the Closing, Mr. Yonehiro, Perseid’s Chief Executive Officer and President, received a grant of 3,750,000 profits interest units under the Equity Incentive Plan.

The foregoing description of the Equity Incentive Plan does not purport to be complete and is qualified in its entirety by reference to the Plan, a copy of which is attached an exhibit to this Current Report on Form 8-K and is incorporated herein by reference.

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Item 8.01 Other Events

The Company held its annual meeting of stockholders (the “Annual Meeting”) on September 17, 2009. At the Annual Meeting, the stockholders approved the Transactions contemplated by the Joint Venture Agreement. At the Annual Meeting, the stockholders also elected Russell Howard, Louis Lange, Kenneth Lee, Ernest Mario, Gordon Ringold, Isaac Stein and James Sulat as directors of the Company and ratified the selection of Ernst & Young LLP as the independent registered public accounting firm of the Company for the fiscal year ending December 31, 2009.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.	Description
2.1(1)	Master Joint Venture Agreement, dated as of June 30, 2009, by and among Maxygen, Inc., Astellas Pharma Inc. and Astellas Bio Inc.
2.1.1	Asset Contribution Agreement, dated as of September 18, 2009, by and between Maxygen, Inc. and Perseid Therapeutics LLC
2.1.2	Technology License Agreement, dated as of September 18, 2009, by and between Maxygen, Inc. and Perseid Therapeutics LLC
2.1.3	Limited Liability Company Agreement of Perseid Therapeutics LLC, dated as of September 18, 2009
2.1.4	Series A and Series B Preferred Unit Purchase Agreement, dated as of September 18, 2009, by and among Maxygen, Inc., Astellas Bio, Inc. and Perseid Therapeutics LLC
2.1.5	Investors’ Rights Agreement, dated as of September 18, 2009 by and between Perseid Therapeutics LLC and the persons and entities listed on Exhibit A thereto
2.1.6	Co-Sale Agreement, dated as of September 18, 2009, by and among Perseid Therapeutics LLC, Maxygen, Inc. and Astellas Bio Inc.
2.1.7	Voting Agreement, dated as of September 18, 2009, by and among Perseid Therapeutics LLC, Maxygen, Inc. and Astellas Bio Inc.
10.1(2)*	Form of Amended and Restated Change of Control Agreement
10.2(3)*	Retention Agreement, dated June 30, 2009, between Maxygen, Inc. and Grant Yonehiro
10.3(4)*	Amended and Restated Change of Control Agreement, dated June 30, 2009, between Maxygen, Inc. and Grant Yonehiro
10.4(5)*	Contingent Offer Letter to Grant Yonehiro from Maxygen, Inc., dated June 26, 2009
10.5*	Perseid Therapeutics LLC 2009 Equity Incentive Plan and related form of profits interest unit agreement
99.1	Press release issued by Maxygen, Inc. on September 21, 2009

* Management contract or compensatory plan or arrangement.

(1) Incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(2) Incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(3) Incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(4) Incorporated by reference to Exhibit 10.3 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(5) Incorporated by reference to Exhibit 10.4 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MAXYGEN, INC.
Date: September 21, 2009	By:	/s/    Russell Howard
		Russell Howard
		Chief Executive Officer

EXHIBIT INDEX

Exhibit No.	Description
2.1(1)	Master Joint Venture Agreement, dated as of June 30, 2009, by and among Maxygen, Inc., Astellas Pharma Inc. and Astellas Bio Inc.
2.1.1	Asset Contribution Agreement, dated as of September 18, 2009, by and between Maxygen, Inc. and Perseid Therapeutics LLC
2.1.2	Technology License Agreement, dated as of September 18, 2009, by and between Maxygen, Inc. and Perseid Therapeutics LLC
2.1.3	Limited Liability Company Agreement of Perseid Therapeutics LLC, dated as of September 18, 2009
2.1.4	Series A and Series B Preferred Unit Purchase Agreement, dated as of September 18, 2009, by and among Maxygen, Inc., Astellas Bio, Inc. and Perseid Therapeutics LLC
2.1.5	Investors’ Rights Agreement, dated as of September 18, 2009 by and between Perseid Therapeutics LLC and the persons and entities listed on Exhibit A thereto
2.1.6	Co-Sale Agreement, dated as of September 18, 2009, by and among Perseid Therapeutics LLC, Maxygen, Inc. and Astellas Bio Inc.
2.1.7	Voting Agreement, dated as of September 18, 2009, by and among Perseid Therapeutics LLC, Maxygen, Inc. and Astellas Bio Inc.
10.1(2)*	Form of Amended and Restated Change of Control Agreement
10.2(3)*	Retention Agreement, dated June 30, 2009, between Maxygen, Inc. and Grant Yonehiro
10.3(4)*	Amended and Restated Change of Control Agreement, dated June 30, 2009, between Maxygen, Inc. and Grant Yonehiro
10.4(5)*	Contingent Offer Letter to Grant Yonehiro from Maxygen, Inc., dated June 26, 2009
10.5*	Perseid Therapeutics LLC 2009 Equity Incentive Plan and related form of profits interest unit agreement
99.1	Press release issued by Maxygen, Inc. on September 21, 2009

* Management contract or compensatory plan or arrangement.

(1) Incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(2) Incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(3) Incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(4) Incorporated by reference to Exhibit 10.3 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

(5) Incorporated by reference to Exhibit 10.4 to the Current Report on Form 8-K filed with the Securities and Exchange Commission on July 1, 2009.

EX-2.1.1

EXHIBIT 2.1.1

ASSET CONTRIBUTION AGREEMENT

by and between

Maxygen, Inc., a Delaware Corporation

and Perseid Therapeutics LLC, a Limited Liability Company

Dated as of September 18, 2009

TABLE OF CONTENTS

		Page
ARTICLE 1	DEFINITIONS	2
ARTICLE 2	THE CONTRIBUTION	12
2.1	Contributed Assets	12
2.2	Excluded Assets	15
2.3	Shared Books and Records	15
2.4	Assumed Liabilities	16
2.5	Excluded Liabilities	17
2.6	Sales and Use Taxes	17
ARTICLE 3	CONSIDERATION	17
3.1	Issuance of Units	17
3.2	Tax-Free Contribution	17
ARTICLE 4	CLOSING AND POST-CLOSING MATTERS	17
4.1	Time and Place of Closing	17
4.2	Closing Deliveries by Contributor	18
4.3	Closing Deliveries by Company	19
4.4	Closing Deliveries by Contributor and Company	19
4.5	Delivery of Contributed Assets	19
4.6	Novation Agreement	20
4.7	Employment Taxes	20
ARTICLE 5	REPRESENTATIONS AND WARRANTIES OF CONTRIBUTOR	20
5.1	Incorporation by Reference	20
5.2	[Reserved]	20
5.3	Transactions with Affiliates	20
5.4	Absence of Changes	21
5.5	Undisclosed Liabilities	21
5.6	Tax Matters	21
5.7	Intellectual Property	22
5.8	Insurance	26
5.9	Title; All Material Assets; Condition of Assets	27
5.10	Real Property Leases	28
5.11	Employees and Consultants	28

TABLE OF CONTENTS

(continued)

5.12	Contributor Benefit Plans	29
5.13	Material Contracts	30
5.14	Restrictions on Business Activities	33
5.15	Compliance with Laws; Governmental Approvals	33
5.16	Proceedings and Orders	34
5.17	Litigation	34
5.18	Environmental Matters	35
5.19	Bulk Sales	36
5.20	No Other Agreement	36
5.21	Power of Attorney	36
5.22	Export Controls; Foreign Corrupt Practices Act	36
5.23	Antiboycott Laws	36
ARTICLE 6	REPRESENTATIONS AND WARRANTIES OF COMPANY	36
6.1	Organization and Qualification	36
6.2	Authority	36
ARTICLE 7	MISCELLANEOUS PROVISIONS	37
7.1	Governing Law	37
7.2	Assignment	37
7.3	Notices	37
7.4	Waiver	39
7.5	Waiver of Jury Trial	39
7.6	Severability	39
7.7	Entire Agreement/Modification	39
7.8	Relationship of the Parties	39
7.9	Force Majeure	40
7.10	Third Party Beneficiaries	40
7.11	Expenses	40
7.12	Further Assurances	40
7.13	Counterparts; Facsimile	41
7.14	Interpretation	41
7.15	Construction	41

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TABLE OF CONTENTS

(continued)

7.16	Provisional Relief; Specific Performance	41
7.17	Confidentiality; Publicity	42
7.18	Indemnification; Sole Remedy; Dispute Resolution	42

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EXHIBITS AND SCHEDULES

Exhibits

Exhibit 4.2(a) Exhibit 4.2(b) Exhibit 4.2(c) Exhibit 4.2(e) Exhibit 4.4(a)	General Assignment and Bill of Sale Form of Patent Assignment Form of Technology License Agreement Forms of Space Sharing Agreements Assignment and Assumption Agreement
Schedules
Schedule 1.12	Employees
Schedule 1.21	Excluded Machinery and Equipment
Schedule 1.22	Excluded Personal Property
Schedule 1.23(a)	Exclusively Out-Licensed Protein
Schedule 1.23(b)	MaxyBody
Schedule 1.26	G&A Function
Schedule 2.1(a)	4 Program Assets
Schedule 2.1(b)(1)	Anticipated Program Proteins or Polypeptides
Schedule 2.1(b)(2)	Other Program Intellectual Property
Schedule 2.1(e)	Other Contributor Intellectual Property
Schedule 2.1(h)	Machinery and Equipment
Schedule 2.1(i)	Personal Property
Schedule 2.1(k)	Personal Property Leases
Schedule 2.1(l)(1)	Contributor Contracts
Schedule 2.1(l)(2)	Excluded Contributor Contracts
Schedule 2.1(m)	Governmental Approvals
Schedule 2.1(n)	Environmental Permits
Schedule 2.1(o)	Assigned Books and Records
Schedule 2.1(p)	Accrued Vacation

The registrant agrees to furnish to the Securities and Exchange Commission upon request a copy of any omitted schedule or exhibit.

ASSET CONTRIBUTION AGREEMENT

This Asset Contribution Agreement (this “Agreement”) is made and entered into as of this 18^th day of September, 2009, by and between Maxygen, Inc., a Delaware corporation, having its principal offices at 515 Galveston Drive, Redwood City, CA 94063 (together with its Affiliates, “Contributor”), and Perseid Therapeutics LLC, a Delaware limited liability company, having its principal offices at 515 Galveston Drive, Redwood City, CA 94063 (“Company”). Contributor and Company are collectively referred to herein as the “Parties.”

RECITALS

WHEREAS, Contributor has conducted discovery, research and development of certain proteins, including certain CTLA-4 proteins, with potential usefulness as human pharmaceutical products, and owns or possesses certain patents and know-how with respect thereto;

WHEREAS, Company desires to discover, develop, manufacture and commercialize protein pharmaceutical products utilizing among other things the core team of personnel currently employed by Contributor in connection with the conduct of such activities, and in connection therewith desires to obtain certain assets and licenses from Contributor related to Contributor’s programs for discovery, research and development of CTLA-4 proteins and, subject to certain exceptions, other protein therapeutics (including assignment to Company of Contributor’s rights and obligations under the Astellas Agreement);

WHEREAS, Contributor desires to contribute to Company, and Company desires to acquire from Contributor, certain assets, properties, rights, claims, liabilities and obligations on the terms and conditions set forth herein in exchange for shares of Series A Preferred Stock of Company to be issued to Contributor therefor (the “Issued Units”) upon the terms and subject to the conditions set forth in the Purchase Agreement (as defined below), which represent the first issuance of Units by the Company;

WHEREAS, immediately following the contribution of assets, properties, rights, claims, liabilities and obligations by Contributor to Company, each of Contributor and Astellas Bio Inc., a Delaware corporation (“Bio”), intends to make a $10,000,000 cash investment in Company in exchange for preferred units of Company pursuant to the Series A and Series B Preferred Unit Purchase Agreement of even date herewith, by and among Company, on the one hand, and Contributor, and Bio, on the other hand (the “Purchase Agreement”);

WHEREAS, concurrently herewith Astellas Pharma Inc., a corporation formed under the laws of Japan (“Astellas”), Astellas US Holding, Inc., a Delaware corporation, Bio, Contributor and Company have entered into other Transaction Agreements;

WHEREAS, the contribution of assets to, and the assumption of the Assumed Liabilities, as defined below, by, Company and the issuance of the Issued Units to Contributor, are each intended to be effected on a tax-free basis pursuant to Section 721 of the Code (and any comparable provisions of applicable state or local tax laws);

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NOW, THEREFORE, in consideration of the foregoing recitals and the mutual representations, warranties, covenants and promises contained herein, the adequacy and sufficiency of which are hereby acknowledged, the Parties hereto agree as follows:

ARTICLE 1

DEFINITIONS

1.1 “Books and Records” means all books, files, papers, correspondence, databases, electronic files, documents (including originals or copies of agreements) and records in Contributor’s possession or control, in whatever medium, excluding (a) originals and drafts of Contracts that are not Contributor Contracts assigned to Company, (b) electronic mail correspondence that are no longer in existence as of the Closing Date or which are deleted in the ordinary course of business under Contributor’s standard retention policy, (c) minutes of meetings of the Board of Contributor and (d) books, files, papers, correspondence, databases, electronic files, documents and records produced in connection with the negotiation of the potential sale of the Business or Contributed Assets to Third Parties (including originals or copies of agreements with such Third Parties with respect to such negotiations) to the extent containing the contents of, or correspondence regarding, such negotiation with such Third Party.

1.2 “Business” means the conduct of the Programs by or for Contributor, including, without limitation, the exploitation of assets and rights and the performance of activities and obligations relevant to the Programs and the discovery, research, development, manufacture, commercialization and other exploitation of Products within the Programs.

1.3 “Code” means the Internal Revenue Code of 1986, as amended.

1.4 “Company Business” means the conduct of the Programs by or for Company or its Affiliates or its licensees, including, without limitation, the exploitation of assets and rights and the performance of activities and obligations relevant to the Programs and the discovery, research, development, manufacture, commercialization and other exploitation of Products within the Programs.

1.5 “Constructive Knowledge” of a Party means, with respect to any fact, circumstance, event or other matter in question, (a) the actual knowledge of such fact, circumstance, event or other matter, or (b) the knowledge of such fact, circumstance, event or other matter that would have been ascertained after reasonable inquiry, consistent with such Person’s title and responsibilities, in either case, by any of the following individuals with respect to such Party or the Party’s employees who directly report to such individuals: Russell Howard, Larry Briscoe, Elliot Goldstein, John Borkholder, Grant Yonehiro, Sridhar Viswanathan, Erik Karrer and Norm Kruse.

1.6 “Contributor Benefit Plans” means every material written, unwritten, formal or informal plan, agreement, program, policy or other arrangement providing for direct or indirect compensation (other than workers’ compensation, unemployment compensation and other government programs), employment, severance, consulting, disability benefits, supplemental unemployment benefits, vacation benefits, retirement benefits, deferred compensation,

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profit-sharing, bonuses, stock options, stock appreciation rights, other forms of incentive compensation, post-retirement insurance benefits, or other benefits, including, without limitation, each “employee benefit plan,” as defined in Section 3(3) of ERISA, which is maintained or contributed to by Contributor or any Member of the Controlled Group for the benefit of any Employee, or pursuant to which the Contributor has or may have any liability with respect to any Employee.

1.7 “Contributor Intellectual Property” means all Intellectual Property included within the Contributed Assets, collectively, the 4 Program Intellectual Property, Other Program Intellectual Property and Other Contributor Intellectual Property. Contributor Intellectual Property does not include any Licensed Intellectual Property.

1.8 “Control” means, with respect to any particular Patent, Intellectual Property Right, Know-How, Technology, Intellectual Property, or other particular asset and any and all rights therein, (a) ownership by the applicable Party or (b) possession by the Party granting the applicable right, license or sublicense to the other Party as provided herein, of the power and authority, whether arising by ownership, license, or other authorization, to disclose, and, if applicable, to deliver the particular Know-How or asset to the other Party, and to grant and to authorize under such Patent or Know-How or asset the right, license or sublicense, as applicable, to such other Party without giving rise to a violation of terms of any written agreement with any Third Party. “Controlled” and “Controlling” shall have their correlative meanings.

1.9 “Copyrights” means all copyrights, and all rights, title and interests in all copyrights, copyright registrations and applications for copyright registration, certificates of copyright and copyrighted interests throughout the world, and all rights, title and interests in related applications and registrations throughout the world.

1.10 “CTLA-4 Variant” has the meaning assigned to it in the Astellas Agreement.

1.11 “Defined Benefit Plan” means either a plan described in Section 3(35) of ERISA or a plan subject to the minimum funding standards set forth in Section 302 of ERISA and Section 412 of the Code.

1.12 “Employee” means the employees of Contributor substantially related to the Programs, who are set forth on Schedule 1.12 attached hereto.

1.13 “Enabling Intellectual Property” means the Enabling Technology as defined under the Technology Licensed Agreement. For clarity, Enabling Technology excludes (a) any Patents listed on Schedules 2.1(a), 2.1(b)(2), or 2.1(e) attached hereto, and (b) any CTLA-4 Variants and Other Protein Variants resulting from the use of the Enabling Technology, together with genetic materials encoding, and cell lines expressing, any such CTLA-4 Variant or Other Protein Variant.

1.14 “Environment” means any ambient workplace, indoor or outdoor air, surface water, drinking water supply, groundwater, or other waterways, land surface or subsurface strata, soil, wildlife, plants, or other natural resources, or buildings, structures and fixtures.

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1.15 “Environmental Claim” means any legal proceeding, order or written notice of violation from any Governmental Authority or any Person alleging liability under any Environmental Law.

1.16 “Environmental Law” means any applicable Legal Requirement concerning: (a) the Environment, including pollution, contamination, cleanup, preservation, protection, and reclamation thereof; (b) human health or safety related to the exposure to a Regulated Substances; (c) any Release or threatened Release of any Regulated Substance; or (d) the management of any Regulated Substance, including the presence, manufacture, generation, use, labeling, warning, notification, treatment, handling, storage, disposal, transportation, re-use, recycling or reclamation of any Regulated Substance.

1.17 “Environmental Permit” means any permit, registration, approval, identification number, license or other authorization required under or issued pursuant to any Environmental Law.

1.18 “ERISA” means the Employee Retirement Income Security Act of 1974, as amended.

1.19 “Excluded Books and Records” means Books and Records other than Assigned Books and Records.

1.20 “Excluded Laboratory Notebooks” means laboratory notebook no. 2183 of Contributor.

1.21 “Excluded Machinery and Equipment” means all tools, machinery and equipment (including manufacturing assembly and test equipment) that are listed on Schedule 1.21 attached hereto.

1.22 “Excluded Personal Property” means all personal property, office furnishings, supplies and other tangible personal listed on Schedule 1.22 attached hereto.

1.23 “Excluded Protein Variant or Vaccine” means (i) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a (A) granulocyte colony stimulating factor (G-CSF), (B) Exclusively Out-Licensed Protein, (C) MaxyBody (which, for the avoidance of doubt, shall not include any Ig portion of a CTLA-4 Variant or Other Protein Variant), (D) a protein from an infectious agent or a polynucleotide encoding such protein that in each case is intended to be used as a Vaccine (including infectious agents or other constructs incorporating a Vaccine and/or genetic material encoding a Vaccine (including live-attenuated or whole killed virus), but solely when such agent, construct or material is included with or otherwise incorporates a protein from an infectious agent (or variant, homolog, derivative, mutant or fragment of such protein as described in (E), below) or a polynucleotide encoding such protein (or such variant, homolog, derivative, mutant or fragment) and is intended to be used as a Vaccine), or (E) any variant, homolog, derivative, mutant, or fragment of subsection (A) or (B) or (D), which in the case of (D) is intended to be used as a vaccine (each, an “Excluded Protein Molecule”) and (ii) any Excluded Protein Molecule that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation). In no event shall Excluded Protein Variants or Vaccines include any CTLA-4 Variants or (x) any

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amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a protein or polypeptide listed on Schedule 2.1(b)(1) attached hereto, or (y) any variant, homolog, derivative, mutant, or fragment of subsection of (x), provided that in the case of (y) such variant, homolog, derivative, mutant, or fragment has not been altered or modified in such a way as to cause such variant, homolog, derivative, mutant, or fragment to fall within (A), (B), (C), or (D) of the definition of Excluded Protein Variant or Vaccine set forth in the first sentence of this Section 1.23, or to fall within (E) above such that a reasonable, independent expert knowledgeable and experienced in working with protein pharmaceuticals would primarily consider such variant, homolog, derivative, mutant, or fragment to be a variant of a protein or polypeptide within (A), (B) or (D) above or a material portion thereof (rather than as a variant of some other protein or material portion thereof). For purposes of this definition of Excluded Protein Variant or Vaccine:

(a) “Exclusively Out-Licensed Protein” has the meaning set forth in Schedule 1.23(a) attached hereto; and

(b) “MaxyBody” shall have the meaning set forth on Schedule 1.23(b) attached hereto.

1.24 “Facility” means, collectively, the laboratory and offices located at 515 Galveston Drive, Redwood City, California 94063 (the “Lab Facility”), and 301 Galveston Drive, Redwood City, California 94063 (the “Office Facility”).

1.25 “Field” shall have the meaning set forth in the Technology License Agreement.

1.26 “G&A Function” means a general and administrative function as is reasonably required to operate the Business consistent with past practice, which shall consist, in all material respects, of those assets and agreements specified on Schedule 1.26 attached hereto.

1.27 “Governmental Approval” means any: permit, license, certificate, concession, approval, consent, ratification, permission, clearance, confirmation, exemption, waiver, franchise, certification, designation, rating, registration, variance, qualification, accreditation or authorization issued, granted, given or otherwise made available by or under the authority of any Governmental Authority or pursuant to any Legal Requirement including, without limitation, any filing or application with the U.S. Food and Drug Administration (the “FDA”), or any foreign counterpart thereof, including investigational new drug applications filed with the FDA as more fully defined in 21 C.F.R. §312.3, and foreign equivalents thereof, but excluding Environmental Permits.

1.28 “Intellectual Property” means (a) Technology and (b) Intellectual Property Rights therein and thereto.

1.29 “Intellectual Property Rights” means any and all rights in and to Technology, including without limitation, Patents, Trade Secrets, Copyrights, Trademarks, moral rights, and mask work rights.

1.30 “Joint Venture Agreement” means the Master Joint Venture Agreement among the Contributor, Bio and Astellas, dated as of June 30, 2009.

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1.31 “Know-How” means any and all data, information and tangible materials including (a) ideas, discoveries, inventions or improvements; (b) research and development data, such as medicinal chemistry data, nonclinical data, preclinical data, pharmacology data, chemistry data (including analytical, product characterization, manufacturing, and stability data), toxicology data, clinical data (including investigator reports (both preliminary and final), statistical analyses, expert opinions and reports, safety and other electronic databases), analytical and quality control data and stability data, in each case together with supporting data; (c) databases, specifications, formulations, formulae; (d) practices, knowledge, techniques, methods, formulas, processes, manufacturing information; and (e) research materials and compositions of matter, including compounds, reagents, clinical candidates, chemical and biological material, cell lines, assays, compound libraries, animal models, and other physical, biological, or chemical material, in each of the foregoing cases, that is Controlled by Contributor. Know-How excludes any Patent rights with respect thereto (but does include information in unpublished patent applications).

1.32 “Laboratory Notebooks” means laboratory notebooks that qualify as Shared Books and Records.

1.33 “Leased Real Property” means all of the Contributor’s rights in the Real Property Lease and the leasehold estate created thereby, together with all of Contributor’s right, title and interest in all land, buildings, structures, easements, appurtenances, improvements (including construction in progress) and fixtures located on the premises described therein;

1.34 “Licensed Intellectual Property” means the Licensed Technology as defined under the Technology License Agreement, which definition, for the avoidance of doubt, includes the Enabling Intellectual Property.

1.35 “Member of the Controlled Group” means each trade or business, whether or not incorporated, that would be treated as a single employer with Contributor under Section 4001 of ERISA or Section 414(b), (c), (m) or (o) of the Code.

1.36 “Multiemployer Plan” means a plan described in Section 3(37) of ERISA.

1.37 “Other Protein Variant” means (a) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a human or animal protein including, without limitation, any protein or polypeptide listed on Schedule 2.1(b)(1) attached hereto, or any variant, homolog, derivative, mutant or fragment of the foregoing subsection (a), including, without limitation, amino acid chains resulting from the use of Shuffling, in each case other than any (i) CTLA-4 Variant or (ii) Excluded Protein Variant or Vaccine, (each such protein or variant, homolog, derivative, mutant or fragment thereof, an “Other Protein Molecule”) and (b) any Other Protein Molecule that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation).

1.38 “Patents” means all patent rights and all rights, title and interests in all patent applications and patents to issue on them, all letters patent or equivalent rights and applications, including utility patents, design patents, plant patents, statutory invention registrations, and any reissue, re-examination, renewal, supplementary protection certificates, extension, division, provisional, substitution, continuation, or continuation-in-part applications thereto throughout the world.

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1.39 “PP&E” means, collectively, (a) Personal Property, (b) Machinery and Equipment and (c) all buildings, structures, improvements, furnishings, furniture, fixtures, displays, appliances and other personal property of every kind and nature owned or leased by the Contributor in connection with the Contributed Assets or the Facility.

1.40 “Programs” mean, collectively, (i) the 4 Program and (ii) the Other Programs.

(a) “4 Program” means any and all activities performed by or on behalf of Contributor, Company or any of their licensees or Affiliates, (i) pursuant to the Astellas Agreement, or (ii) otherwise directed to any CTLA-4 Variant including, without limitation, activities for the discovery, research, development, manufacture, commercialization or other exploitation of any CTLA-4 Variant or CTLA-4 Product intended for use in the Field.

(b) “Other Programs” means, individually and collectively, any and all activities performed by or on behalf of Contributor, Company or any of their licensees or Affiliates, directed to any Other Protein Variant including, without limitation, activities for the discovery, research, development, manufacture, commercialization or other exploitation of any Other Protein Variant or Other Protein Product intended for use in the Field.

1.41 “Products” mean, collectively, (i) any CTLA-4 Product and (ii) any Other Protein Product.

(a) “CTLA-4 Product” means any pharmaceutical product that contains a CTLA-4 Variant as an ingredient. For the avoidance of doubt, CTLA-4 Product shall include any formulation, delivery device, dispensing device or packaging required for effective use of the CTLA-4 Product.

(b) “Other Protein Product” means any pharmaceutical product that contains an Other Protein Variant as an ingredient. For the avoidance of doubt, Other Protein Product shall include any formulation, delivery device, dispensing device or packaging required for effective use of the Other Protein Product; provided, however, that Other Protein Product shall exclude all Vaccines.

1.42 “Real Property Lease” means, collectively, (a) that certain Lease between Metropolitan Life Insurance Company, as lessor, and Contributor, as lessee, dated as of October 21, 1998, as amended to date, for certain premises consisting of the Lab Facility, and (b) that certain Lease between Metropolitan Life Insurance Company, as lessor, and Contributor, as lessee, dated December 2004, as amended to date, for certain premises consisting of the Office Facility.

1.43 “Registered Intellectual Property Rights” means all United States, international and foreign: (a) Patents, including applications therefor; (b) registered Trademarks, applications to register Trademarks, including intent-to-use applications, or other registrations or applications related to Trademarks; (c) Copyrights registrations and applications to register Copyrights; and (d) any other Technology that is the subject of an application, certificate, filing, registration or other document issued by, filed with, or recorded by, any state, government or other public or private legal authority at any time.

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1.44 “Regulated Substances” means any material, waste or substance that in relevant quantity, form and or concentration is listed, defined, classified, controlled or regulated by any Governmental Authority as “hazardous,” “toxic,” or a “pollutant,” or “contaminant,” pursuant to any Environmental Law, including but not limited to any explosives, radon, radioactive materials, friable asbestos, urea formaldehyde foam insulation, polychlorinated biphenyls, petroleum and petroleum products (including waste petroleum and petroleum products).

1.45 “Release” shall have the same meaning as under 42 USC Section 9601(22) of the Comprehensive Environmental Responsibility Compensation & Liability Act of 1980 (“CERCLA”).

1.46 “Remedial Action” shall have the same meaning as under 42 USC Section 9601(24) of the CERCLA.

1.47 “Shared Books and Records” shall mean all Books and Records (Assigned Books and Records and/or Excluded Books and Records, as the case may be) that relate to the Contributed Assets and/or Assumed Liabilities and/or the Programs but that also relate to the Excluded Assets and/or Excluded Liabilities and/or programs or activities of Contributor as of or prior to the Effective Date other than Programs.

1.48 “Shuffling” means techniques, methodologies, processes, materials or instrumentation for performing recombination-based modification of genetic material for the creation of potentially useful variant nucleic acids or proteins. “Shuffle” and “Shuffled” have their correlative meanings.

1.49 “Subsidiaries” shall refer to Maxygen ApS (Denmark) and Maxygen Holdings Ltd. (Cayman Islands).

1.50 “Technology” means any or all of the following: (a) works of authorship including, without limitation, computer programs, source code and executable code, whether embodied in software, firmware or otherwise, documentation, designs, files, net lists, records, data and mask works; (b) inventions (whether or not patentable and whether or not reduced to practice), improvements, and technology; (c) proprietary and confidential information and materials, including technical data and customer and supplier lists, Trade Secrets, discoveries, processes, formulas, and other Know-How; (d) databases, data compilations and collections and technical data; and (e) all copies and instantiations of the foregoing in any form and embodied in any media, in each of the foregoing cases that is Controlled by Contributor.

1.51 “Trademarks” means all trademarks, service marks, trade names, rights in trade dress, logos, slogans, trade names, internet domain names and addresses, and all trademark interests throughout the world together with all translations, adaptations, derivations, and combinations thereof and including all goodwill associated therewith, and all right, title and interest in related applications, registrations, and renewals throughout the world, whether arising under the laws of the United States or any other country or other jurisdiction.

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1.52 “Trade Secrets” means all trade secrets under applicable law and other rights in Know-How, and confidential or proprietary information, processing, manufacturing or marketing information, new developments, research, inventions, processes, ideas or other proprietary information that provide Contributor with advantages over competitors who do not have access to such information and documentation thereof (including related papers, blueprints, drawings, chemical compositions, formulae, diaries, notebooks, specifications, designs, methods of manufacture and data processing software, compilations of information) and all claims and rights related thereto.

1.53 “Transfer Taxes” means all federal, state, local or foreign sales, use, transfer, real property transfer, mortgage recording, stamp duty, value-added or similar Taxes that may be imposed in connection with the transfer of Contributed Assets or assumption of Assumed Liabilities, together with any interest, additions to Tax or penalties with respect thereto and any interest in respect of such additions to Tax or penalties.

1.54 “Vaccine” means a formulation intended to be administered in a formulation containing one or more Antigen(s) (and/or a nucleic acid sequence encoding an Antigen) in the form of (i) an infectious agent (e.g., bacteria, viruses, parasite, protozoa) whether live, attenuated or dead, (ii) protein(s), (iii) nucleic acid(s), (iv) cells, spores and vectors (i.e., viruses and/or virus-like particles, liposomes, beads and/or other substrates for Antigen presentation), (v) fragments of any of the foregoing, and/or (vi) a combination of any of the preceding, which formulation is administered for the purpose of inducing an Immune Response in the human and/or animal recipient specifically directed to at least one such Antigen for the prevention or treatment of a disease state, symptom and/or condition in humans and/or animals caused by an infectious agent. For the purposes of this definition of Vaccine:

(a) “Antigen” means a molecule (i.e., protein, polypeptide, peptide, carbohydrate, glycoprotein, glycolipid and/or any combination of the foregoing that is, or is derived in whole or part from, a molecule associated with an infectious agent) that produces an Immune Response to such molecule in a human and/or animal recipient.

(b) “Immune Response” means an immune state directed to the applicable infectious agents (or a molecule associated with such infectious agent) resulting from the modulation of activity (i.e., an increase, decrease and/or qualitatively different activity) of one or more lymphoid cells (e.g., B cells, NK cells, T cells and/or professional antigen-presenting cells, such as monocytes, macrophages, Langerhans cells, dendritic cells) following the administration of a stimulus.

1.55 All other capitalized terms used herein shall have the meanings ascribed to them herein or in the Joint Venture Agreement as set forth below:

Term	Reference (*)
4 Program	1.40(a)
4 Program Intellectual Property	2.1(a)
Accrued Vacation	2.1(p)
Affiliate	JVA 1.2
Agreement	Preamble

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Term	Reference (*)
Alk-Abello Agreement	2.2(f)
Antigen	1.54(a)
Assigned Books and Records	2.1(o)
Assignment and Assumption	4.4(a)
Assumed Liabilities	2.4
Astellas	Recitals
Astellas Agreement	JVA 1.6
Astellas Agreement Assignment and Novation	2.1(d)
Bio	Recitals
Board	JVA 1.9
Bridge Loan Agreement	JVA 1.10
Business Day	JVA 1.12
Business Governmental Approvals	5.15(b)
CERCLA	1.45
Closing	4.1
Closing Date	JVA 1.16
Company	Preamble
Confidential Information	JVA 1.19
Consent	JVA 1.21
Contract	JVA 1.22
Contributed Assets	2.1
Contributor	Preamble
Contributor Contracts	2.1(l)
Contributor Disclosure Schedule	ARTICLE 5
Contributor Liabilities	5.5
Contributor Registered Intellectual Property Rights	5.7(a)
CTLA-4 Product	1.41(a)
Dollars / $	JVA 1.28
Encumbrance	JVA 1.30
Entity	JVA 1.31
Excluded Assets	2.2
Excluded Contributor Contracts	2.1(l)
Excluded Liabilities	2.5
Excluded Protein Molecule	1.23
Exclusively Out-Licensed Protein	1.23(a)
FDA	1.27
Financial Statements	5.3
General Assignment and Bill of Sale	4.2(a)
Governmental Authority	JVA 1.37
Immune Response	1.54(b)
Insurance Policies	5.8

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Term	Reference (*)
Investors’ Rights Agreement	JVA 1.39
Issued Units	Recitals
Knowledge	JVA 1.42
Lab Facility	1.24
Legal Requirement	JVA 1.43
Liability	JVA 1.44
Machinery and Equipment	2.1(h)
Material Adverse Effect	JVA 1.45
Material Contracts	5.13(a)
MaxyBody	1.23(b)
Maxygen JVA Disclosure Schedule	JVA Article 4
Non-Assignable Asset	JVA 8.1
Offerees	JVA 5.5(a)
Office Facility	1.24
Order	JVA 1.48
Other Contributor Intellectual Property	2.1(e)
Other Programs	1.40(b)
Other Program Intellectual Property	2.1(b)
Other Protein Molecule	1.37
Other Protein Product	1.41(b)
Patent Assignment	4.2(b)
Parties	Preamble
Permitted Encumbrance	JVA 1.52
Permitted Uses	2.3
Person	JVA 1.53
Personal Property	2.1(i)
Personal Property Leases	2.1(k)
Proceeding	JVA 1.55
PTO	5.7(a)
Purchase Agreement	Recitals
Related Entity	JVA 1.59
Representatives	JVA 1.60
SEC	JVA 1.61
Space Sharing Agreements	4.2(e)
Tax	JVA 1.66
Tax Authority	JVA 1.67
Tax Returns	5.6(a)
Technology License Agreement	4.2(c)
Third Party	JVA 1.70

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Term	Reference (*)
Transaction Agreements	JVA 1.71
Transactions	JVA 1.72
Transition Services Agreement	JVA 1.73
Transferred Employees	JVA 5.5(b)
UCOE License Assignment Agreement	2.1(f)
United States	JVA 1.75

* For the purpose of this Section 1.55 only, “JVA” means the Joint Venture Agreement. References to Preambles, Recitals, Articles and numbers mean Preambles Recitals, Articles and Section numbers of this Agreement, respectively, unless “JVA” is attached thereto, in which case those words refer to Recitals and Sections mean Preambles Recitals, Articles and Section numbers of the Joint Venture Agreement, respectively.

ARTICLE 2

THE CONTRIBUTION

2.1 Contributed Assets. Subject to the terms and conditions of this Agreement, at the Closing, Contributor shall contribute, transfer, convey, assign and, subject to and in accordance with Section 4.5 hereof, deliver to Company, and Company shall acquire from Contributor, all of Contributor’s right, title and interest in the assets, properties, goodwill and rights of Contributor that are primarily used (or primarily have been used) in, result from (to the extent provided below), or primarily relate to, the conduct of the Business as of or prior to the Closing Date of every nature, kind and description, tangible and intangible, wherever located, whether or not carried on the books of Contributor, free and clear of all Encumbrances (collectively, the “Contributed Assets”), including, without limitation, the assets listed below, except those assets expressly identified as Excluded Assets in Sections 2.2(a)-2.2(i) hereof. Where reference is made to assets, properties, goodwill and rights that “have been used in [. . .] the conduct of the Business,” such references shall be interpreted to mean only the relevant assets, properties, goodwill and rights that Contributor owns or otherwise has rights to as of the Closing Date.

(a) The 4 Program Assets. All Intellectual Property Controlled by Contributor (i) resulting from or generated under the 4 Program as conducted by or for Contributor as of or prior to the Closing Date (including all CTLA-4 Variants), or (ii) primarily used (or primarily have been used) in, or primarily useful for, the 4 Program or both the 4 Program and the Other Programs in each case as conducted (or anticipated to be conducted) by or for Contributor as of or prior to the Closing Date, in each case excluding all Licensed Intellectual Property, but including, without limitation, the Intellectual Property listed on Schedule 2.1(a) attached hereto and all Intellectual Property owned by Contributor and licensed to Astellas under the Astellas Agreement (“4 Program Intellectual Property”);

(b) Other Program Assets. All Intellectual Property Controlled by Contributor (i) resulting from or generated under the Other Programs as conducted by or for Contributor prior

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to the Closing Date (including, without limitation, work conducted on the Other Programs between the date of execution of this Agreement and the Closing Date) that is primarily related to, or primarily useful for, the Other Programs or the 4 Program (including the proteins and polypeptides listed on Schedule 2.1(b)(1) attached hereto, and any Other Protein Variants), or (ii) primarily used (or primarily have been used) in, or primarily useful for, a particular Other Program as conducted (or anticipated to be conducted) by or for Contributor as of or prior to the Closing Date, to the extent transferable or assignable, in each case excluding all Licensed Intellectual Property, but including, without limitation, the Intellectual Property listed on Schedule 2.1(b)(2) attached hereto (“Other Program Intellectual Property”);

(c) License. Concurrently with this Agreement, Contributor shall grant to Company licenses (or sublicenses, as applicable) under the Licensed Intellectual Property Controlled by Contributor for the purpose of conducting the 4 Program and Other Programs, all as set forth in, and on the terms and conditions set forth in, the Technology License Agreement;

(d) Astellas Agreement. All of Contributor’s rights and obligations under the Astellas Agreement other than rights to payments thereunder that accrue prior to the Closing Date, but including Contributor’s right to receive certain milestone, royalty and other payments thereunder accruing on or after the Closing Date, as set forth in the Astellas Agreement Assignment and Limited Novation (“Astellas Agreement Assignment and Novation”);

(e) Other Intellectual Property. All Intellectual Property, if any, Controlled by Contributor as of the Closing Date that are primarily used in (or primarily have been used) as of or prior to the Closing Date, or primarily useful for, more than one particular Program that is not otherwise included in the 4 Program Intellectual Property or Other Program Intellectual Property under Section 2.1(a) or 2.1(b)(2) hereof, but excluding all Licensed Intellectual Property and, for clarity, excluding all Intellectual Property that is primarily used (or primarily has been used) by Contributor or its Affiliates other than for conducting Programs, but including the Intellectual Property listed on Schedule 2.1(e) attached hereto (“Other Contributor Intellectual Property”);

(f) UCOE License. All of Contributor’s rights and obligations under the Research and Commercial UCOE License Agreement between ML Laboratories PLC and Maxygen ApS and Maxygen, Inc. and Maxygen Holdings Ltd. dated May 27, 2005, other than payments thereunder that accrue prior to the Closing Date, as set forth in the UCOE License Assignment Agreement (“UCOE License Assignment Agreement”);

(g) [Reserved];

(h) Machinery and Equipment. All tools, machinery and equipment (including manufacturing assembly and test equipment) owned by Contributor that are used (or have been used) in the Programs as conducted by Contributor as of or prior to the Closing Date or that are used (or have been used) in the G&A Function, wherever located and whether held by Contributor or Third Parties, except for Excluded Machinery and Equipment, including the Machinery and Equipment listed on Schedule 2.1(h) attached hereto (the “Machinery and Equipment”);

(i) Personal Property. All personal property, office furnishings, supplies and other tangible personal property that are used (or have been used) in the Programs or the G&A

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Function as of or prior to the Effective Date and owned by Contributor, whether held by Contributor or Third Parties, except for Excluded Personal Property (the “Personal Property”) including, without limitation, the items listed on Schedule 2.1(i) attached hereto;

(j) [Reserved];

(k) Personal Property Leases. All rights in leases of personal property including, without limitation, leased equipment that are used (or have been used) in the Business or the G&A Function, including, without limitation, the items listed on Schedule 2.1(k) (including without limitation the transfer of the personal property so leased) attached hereto, and excluding all rights in leases related to Excluded Machinery and Equipment and Excluded Personal Property (the “Personal Property Leases”);

(l) Contracts. All rights to or under any and all contracts, agreements (including grant agreements) or commitments that primarily relate to, or are primarily useful for, the Programs (but for the avoidance of doubt excluding all contracts, agreements or commitments primarily related to the Licensed Intellectual Property) and are assignable to Company, as listed on Schedule 2.1(l)(1) attached hereto, (collectively, the “Contributor Contracts”); all such contracts, agreements (including grant agreements) or commitments that would meet the foregoing definition but for the fact that they are not assignable, or the Parties have agreed not to assign to Company, are listed on Schedule 2.1(l)(2) attached hereto (collectively, “Excluded Contributor Contracts”).

(m) Governmental Approvals. All Governmental Approvals (and pending applications therefor), including any formal correspondence to or from the FDA, that are used (or have been used) in the operation of the Programs, as listed on Schedule 2.1(m) attached hereto, to the extent transferable or assignable;

(n) Environmental Permits. All Environmental Permits that are used in the operation of the Programs, as listed on Schedule 2.1(n) attached hereto, to the extent transferable or assignable.

(o) Assigned Books and Records. All Books and Records that (i) primarily relate to the Contributed Assets and/or Assumed Liabilities or (ii) arose out of or primarily relate to the conduct of the 4 Program by or for Contributor or that primarily relate to the Other Programs (the “Assigned Books and Records”), including, without limitation, those Books and Records listed on Schedule 2.1(o), in each case subject to any applicable Legal Requirements (including any required releases that may need to be obtained from the Offerees) and provided that Assigned Books and Records may include Books and Records that Contributor may be required by law to retain in its possession; and

(p) Funds to cover Accrued Vacation. A lump sum payment from Contributor to Company at the Closing for the amount of accrued and unpaid days of vacation earned by the Transferred Employees who commence employment with Company under Contributor’s vacation policies as of the Closing Date, as set forth in Schedule 2.1(p) attached hereto, which schedule may be updated (and the lump sum payment provided for shall be increased or decreased, as appropriate) as necessary by Contributor up to the Closing to reflect any subsequent changes in the vacation balances for such employees (“Accrued Vacation”).

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2.2 Excluded Assets. Contributor does not contribute, transfer, convey or assign any assets, properties, goodwill or rights to Company other than the Contributed Assets (“Excluded Assets”). Company acknowledges that this Agreement shall give Company no rights to any Excluded Assets and rights expressly granted pursuant to this Agreement and/or the Transaction Agreements, including any drug research or development program, drug target, product, product candidate or prospective product candidate of Contributor. Specifically, the following assets are included among the Excluded Assets and are excluded from the contribution, transfer, conveyance, assignment or delivery provided for under Section 2.1 hereof:

(a) the Licensed Intellectual Property including the Enabling Intellectual Property and any Copyrights in software or computer code within the Licensed Intellectual Property (except, in all such cases, to the extent licensed or sublicensed to Company under the Technology License Agreement);

(b) Excluded Books and Records;

(c) Excluded Machinery and Equipment;

(d) Excluded Personal Property;

(e) Excluded Contributor Contracts;

(f) All proteins, nucleic acid chains, cell lines and other biological materials, and all data and information, resulting from or generated under the programs directed to allergens conducted by or for Contributor prior to the Closing Date under the Collaboration Agreement between Maxygen, Inc. and Alk-Abelló AS dated February 8, 2001, (the “Alk-Abello Agreement”), and Intellectual Property Rights in and to the foregoing which Intellectual Property Rights (i) resulted from or were generated under the programs related to allergens conducted by or for Contributor prior to the Closing Date under the Alk-Abello Agreement and (ii) are solely related to, or solely useful for, the discovery, research, development, manufacture, commercialization or other exploitation of one or more allergens;

(g) All Trademarks of Contributor;

(h) All Contributor Benefit Plans, and all assets owned or held by all Contributor Benefit Plans; and

(i) Any real property leases or other interests in real property except pursuant to the Space Sharing Agreements.

2.3 Shared Books and Records. Contributor shall provide Company with access to Assigned Books and Records that are Shared Books and Records and Company shall provide Contributor with access to Excluded Books and Records that are Shared Books and Records to the extent permitted by applicable law. Each of Contributor and Company shall permit the other to make copies of or other extracts from such Shared Books and Records and, upon request, provide

15

assistance in accessing Shared Books and Records in the other’s possession (it being understood that each of Contributor and Company shall be entitled to access and/or copy directly any Shared Books and Records owned by the other which are already accessible to such Party without notifying or asking the other Party). Without limiting the foregoing, Contributor shall deliver to Company copies, certified as true and correct, of all Laboratory Notebooks that are Excluded Books and Records, other than certain portions of the Excluded Laboratory Notebook, in accordance with Section 4.5 hereof. Contributor shall only be required to deliver to Company a copy of the portions of the Excluded Laboratory Notebook relating to CTLA-4 Variants or the 4 Program and to make available the original thereof in limited circumstances as described in Section 4.5 hereof. Subject to the requirements of Section 8.7 of the Joint Venture Agreement, each of Contributor and Company shall have (and hereby grant each other) a worldwide, fully paid, nonexclusive, perpetual, non-revocable license to use, reproduce, distribute, and make derivative works of, the Shared Books and Records solely for the Permitted Uses. “Permitted Uses” shall mean (a) with respect to Contributor, any purpose reasonably related to its operation of its business, other than the Business, and its ownership and exploitation of the Excluded Assets, and (b) with respect to Company, any purpose reasonably related to its operation of the Business and its ownership and exploitation of the Contributed Assets, in each case subject to applicable terms and conditions (including applicable obligations of confidentiality) set forth in the Transaction Agreements. For the avoidance of doubt, the provisions in this Agreement regarding the Books and Records (including the assignment, retention and/or sharing thereof) shall not affect the terms and conditions regarding (nor increase or decrease any rights with respect to, or ownership of) Patents and/or Know How (including any assignment, retention and/or license thereof) in this Agreement or the other Transaction Agreements.

2.4 Assumed Liabilities. Subject to the terms and conditions of this Agreement, at the Closing, Contributor shall assign, and Company shall assume, the Assumed Liabilities. For the purposes of this Agreement, the “Assumed Liabilities” means only the following Liabilities of Contributor, and in any event shall not include any Excluded Liabilities:

(a) Any Liability arising before or after the Closing Date under the Astellas Agreement (excluding amounts payable thereunder that have accrued prior to the Closing Date), and except as provided in the Astellas Agreement Assignment and Novation, and any Liability arising after the Closing Date under any Contributor Contracts excluding in each case any Liability for Contributor’s Employees (except as provided in this Section 2.4);

(b) All Liabilities arising after the Closing Date under the Technology License Agreement;

(c) [Reserved];

(d) All Liabilities arising after the Closing Date under the Personal Property Leases;

(e) All Liabilities for providing Accrued Vacation to the Transferred Employees who commence employment with the Company;

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(f) Subject to and excluding any Liabilities to be borne by Contributor as expressly provided under this Agreement or the Transaction Agreements, all Liabilities of Contributor under or in respect of any other Contributed Asset to the extent that such Liabilities are incurred after the Closing Date and are required to be performed after the Closing Date; and

(g) All employment-related Liabilities relating to the Transferred Employees arising on or after the Closing Date; provided that such employees commence employment or other service provider relationship with Company (excluding Liabilities pursuant to Contributor Benefit Plans except as provided in the Transition Services Agreement and other than Liabilities for Accrued Vacation as provided in Section 2.4(e) hereof).

2.5 Excluded Liabilities. Except for the Assumed Liabilities, Company shall not assume and shall not be deemed to have assumed or be liable or responsible for, any Liability of Contributor or any Affiliate of Contributor (collectively, the “Excluded Liabilities”).

2.6 Sales and Use Taxes. Contributor shall bear and pay any and all Transfer Taxes arising out of the transfer of the Contributed Assets to Company. To the extent permitted by applicable law, Company and Contributor shall use commercially reasonable efforts to minimize such Transfer Taxes, including, without limitation, by ensuring that the Issued Units issued to Contributor pursuant to this Agreement are the first issuance of units by the Company.

ARTICLE 3

CONSIDERATION

3.1 Issuance of Units. As consideration for Contributor’s contribution of the Contributed Assets to Company, subject to the terms of this Agreement and the Purchase Agreement, on the Closing Date, Company shall issue to Contributor the Issued Units as provided in the Purchase Agreement.

3.2 Tax-Free Contribution. Contributor and Company acknowledge and agree that the issuance of the Issued Units to Contributor pursuant to this Agreement is intended to qualify as an issuance of shares which is described in Section 721 of the Code (and any comparable provisions of applicable state or local tax laws), and Contributor and Company agree to report and treat the transactions described in this Agreement consistently therewith.

ARTICLE 4

CLOSING AND POST-CLOSING MATTERS

4.1 Time and Place of Closing. The closing of the contribution and the other transactions provided for in this Agreement shall take place remotely via exchange of closing deliverables, including executed documents, on the Closing Date or at such other place as Contributor and Company mutually agree upon, orally or in writing; provided that in any event, the Closing shall be deemed to have occurred simultaneously with the closing of the issuance and sale of the Issued Units (which consummation of such transactions at such time and place is designated as the “Closing”).

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4.2 Closing Deliveries by Contributor. At the Closing, Contributor shall deliver the following items to Company, duly executed by Contributor, as applicable, all of which shall be in form and substance reasonably acceptable to Company (provided that any items in substantially the form attached as a schedule or exhibit to this Agreement shall be deemed to be reasonably acceptable to Company):

(a) General Assignment and Bill of Sale. General Assignment and Bill of Sale covering all of the applicable Contributed Assets, substantially in the form attached hereto as Exhibit 4.2(a) (the “General Assignment and Bill of Sale”);

(b) Intellectual Property Assignment. Without limiting inclusion of any applicable Intellectual Property under Section 4.2(a) hereof, any and all documents necessary to properly record and effectuate the assignment and transfer to Company of all of Contributor’s right, title and interest in and to the Contributor Registered Intellectual Property, including a patent assignment (the “Patent Assignment”) substantially in the form of Exhibit 4.2(b) hereto, for all of the Patents that are part of the Contributor Registered Intellectual Property, duly executed by Contributor;

(c) Technology License Agreement. An agreement in substantially the form of Exhibit 4.2(c) attached hereto (the “Technology License Agreement”), pursuant to which Contributor will grant to Company certain licenses (or sublicenses, as applicable) under the Licensed Intellectual Property Controlled by Contributor for purposes of conducting the 4 Program and Other Programs, all as set forth in, and on the terms and conditions set forth in, the Technology License Agreement;

(d) [Reserved]

(e) Space Sharing Agreements for Facility and Assignment of Personal Property Leases. Space sharing agreements (the “Space Sharing Agreements”) for substantially all of the Lab Facility and a portion of the Office Facility in the forms attached hereto as Exhibit 4.2(e) attached hereto and assignments of the Personal Property Leases duly executed by Contributor and the consent thereto by the lessor(s) to the extent required pursuant to the terms of such leases (in form and substance reasonably satisfactory to Company);

(f) Consents; Acknowledgements. Duly executed Consents of all Third Parties required by Contributor to consummate the Transactions, in form and substance reasonably satisfactory to Company, if any, as well as any notices and/or acknowledgements required to be provided to Third Parties in connection with the assignment of any Contributor Contracts, as listed in Schedule 4.2(f) attached hereto.

(g) Contributor Contracts. Originals or true, correct and complete copies of all Contributor Contracts;

(h) [Reserved]

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(i) Books and Records. Subject to Section 4.5 hereof, the Assigned Books and Records.

4.3 Closing Deliveries by Company. At the Closing, Company shall deliver the following items to Contributor:

(a) Unit Certificate. A certificate representing the Issued Units as specified in Section 1.2(b) of the Purchase Agreement in exchange for the Contributed Assets.

(b) Acknowledgements. Duly executed notices and/or acknowledgements required to be provided to Third Parties in connection with the assignment of any Contributor Contracts, as listed in Schedule 4.2(f) attached hereto.

4.4 Closing Deliveries by Contributor and Company. At the Closing, Contributor and Company shall deliver the following items to one another, duly executed:

(a) Assignment and Assumption Agreement. Assignment and Assumption Agreement, covering all of the Assumed Liabilities (including assignment and assumption of the Contributor Contracts), substantially in the form attached hereto as Exhibit 4.4(a) (the “Assignment and Assumption”) and executed counterparts of the documents described in Sections 4.2(c) and 4.2(e) hereof.

4.5 Delivery of Contributed Assets. Subject to the terms and conditions hereof and of the Transition Services Agreement and to the extent that Contributor has the power to do so, Contributor shall, at the Closing, (i) take all steps necessary to place Company in actual possession and operating control of all Contributed Assets that are tangible assets, including original copies of the Assigned Books and Records and copies, certified as true and correct, of the Laboratory Notebooks that are Excluded Books and Records (including the portions of the Excluded Laboratory Notebook that relate to CTLA-4 Variants or the 4 Program but excluding any other portions of such Excluded Laboratory Notebook), and (ii) to deliver to Company such instruments as are necessary or desirable to document and to transfer title to all intangible Contributed Assets from Contributor to Company. To the extent that Contributor cannot grant possession of any Contributed Asset to Company as of the Closing, (A) those assets shall be held by Contributor for and on behalf of Company until such time as Company or its designee is granted possession thereof and (B) Contributor shall use its commercially reasonable efforts to deliver possession of such Contributed Asset to Company pursuant to a schedule to be agreed to by Contributor and Company or, except as otherwise agreed by the Parties, within thirty (30) days following the Closing. Each Party shall provide the other Party with reasonable access to Contributed Assets or Excluded Books and Records (including originals thereof and including originals of the Excluded Laboratory Notebook) to the extent reasonably necessary for use in connection with any actual or threatened action, suit, inquiry, investigation or proceeding involving such other Party (whether existing presently or in the future) before any arbitrator or Governmental Authority or by any Governmental Authority (provided that any originals are returned to the owning Party following such use and provided that the Parties will work in good faith to share access during any such time that the other Party is in possession of such asset(s) pursuant to this Section 4.5 to the extent necessary to permit the Party to comply with its other contractual obligations).

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4.6 Novation Agreement. Upon Contributor’s request, Company shall reasonably cooperate with Contributor to execute, and to obtain the applicable counterparty’s agreement to, any Novation Agreement in a form acceptable to the Parties which is submitted by Contributor to a counterparty to any Contributor Contract.

4.7 Employment Taxes. Contributor and the Company shall, if administratively feasible, use best reasonable efforts to, with respect to Transferred Employees who are employed by the Company for the tax year in which the Closing Date occurs, (i) treat the Company as a “successor employer” and Contributor as a “predecessor employer” for purposes of Sections 3121(a)(1) and 3306(b)(1) of the Code, and (ii) adopt the “alternative procedure” for preparing and filing IRS Forms W-2 (Wage and Tax Statements) as described in IRS Revenue Procedure 2004-53, 2004-2 C.B. 320 (2004).

ARTICLE 5

REPRESENTATIONS AND WARRANTIES OF CONTRIBUTOR

Except as set forth in the corresponding sections of the disclosure schedule of Contributor delivered to Company concurrently with the execution and delivery of this Agreement (the “Contributor Disclosure Schedule”) or as disclosed in the reports, schedules, forms, statements and other documents filed by Contributor with the SEC (and with respect to such reports, schedules, forms, statements and other documents filed prior to January 1, 2009 such items shall be and specifically cross referenced in the Contributor Disclosure Schedule), Contributor hereby represents and warrants to the Company that, as of the date hereof:

5.1 Incorporation by Reference. Subject to Section 9.7 of the Joint Venture Agreement, all representations and warranties of Contributor set forth in Section 4.1 of the Joint Venture Agreement are hereby incorporated by reference as if fully set forth herein, as qualified by the Maxygen JVA Schedule.

5.2 [Reserved]

5.3 Transactions with Affiliates. Except as set forth in the financial statements of Contributor included in Contributor’s Annual Report on Form 10-K for the period ended December 31, 2008, filed with the SEC on March 12, 2009, as amended on April 28, 2009 (the “Financial Statements”), no Affiliate of Contributor (a) has any direct or indirect interest in any asset (including the Contributed Assets), property or other right that are used (or have been used) in the conduct of or otherwise related to the Business; (b) has any claim or right against Contributor, and no event has occurred, and no condition or circumstance exists, that might (with or without notice or lapse of time) directly or indirectly give rise to or serve as a basis for any claim or right in favor of any Affiliate against the Business and/or the Contributed Assets; (c) is a party to any Contributor Contract or has had any direct or indirect interest in, any Contributor Contract, transaction or business dealing with Contributor that pertains to the Business; or (d) received from or furnished to Contributor any goods or services (with or without consideration) since December 31, 2008 in respect of the Business.

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5.4 Absence of Changes. Except as otherwise expressly contemplated by the Transaction Agreements, since December 31, 2008, (i) Contributor has conducted the Business in the ordinary course of business; (ii) no event or circumstance has occurred that would reasonably be expected to result in a Material Adverse Effect with respect to Contributor; and (iii) Contributor has not taken any action that would constitute a breach of Sections 5.1 and 5.2 of the Joint Venture Agreement such as would reasonably be expected to result in a Material Adverse Effect with respect to Contributor if such action or omission were taken between the date of the Joint Venture Agreement and the Closing Date (provided that for the purposes of this clause (iii), all references to “material,” “materially,” “Material Adverse Effect” and words of like import shall be deemed to be deleted in Sections 5.1 and 5.2 of the Joint Venture Agreement for this purpose).

5.5 Undisclosed Liabilities. Contributor has no Liability relating to the Business or the Contributed Assets (the “Contributor Liabilities”) other than (i) Contributor Liabilities reflected on the Financial Statements, (ii) Contributor Liabilities not required to be reflected on Contributor’s financial statements under GAAP, (iii) Contributor Liabilities that have arisen after December 31, 2008 in the ordinary course of business or (iv) Contributor Liabilities arising under the Transaction Agreements.

5.6 Tax Matters.

(a) To the extent that failure to do so would adversely impact the Business or the Company Business, the Contributed Assets or Contributor’s ownership of the Contributed Assets, Contributor (i) has timely paid all Taxes it is required to pay and (ii) has timely filed all required federal, state, local and foreign returns, estimates, information statements and reports (“Tax Returns”) relating to any and all Taxes concerning or attributable to the Contributed Assets and such Tax Returns are true and correct and completed in accordance with applicable law.

(b) Contributor has, in all material respects, timely paid or withheld with respect to the Transferred Employees (and timely paid over any withheld amounts to the appropriate Tax Authority) all federal and state income taxes, Federal Insurance Contribution Act, Federal Unemployment Tax Act and other Taxes required to be withheld or paid.

(c) Contributor does not have Knowledge of any basis for the assertion of any claim for any material liabilities for unpaid Taxes for which Company would become liable as a result of the transactions contemplated by this Agreement or that would result in any Encumbrance on any of the Contributed Assets.

(d) There are no Encumbrances with respect to any Taxes upon any of the Contributed Assets, other than with respect to Taxes not yet due and payable.

(e) To the extent applicable to the Business, the Contributed Assets or Company’s ownership of the Contributed Assets, Contributor has not been delinquent in the payment of any Tax, nor is there any Tax deficiency outstanding, assessed or proposed against Contributor, nor has Contributor executed any outstanding waiver of any statute of limitations on or extension of the period for the assessment or collection of any Tax.

(f) To the extent applicable to the Business, the Contributed Assets or Company’s ownership of the Contributed Assets, (i) no audit or other examination of any Tax

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Return of Contributor is presently in progress, nor has Contributor been notified of any request for such an audit or other examination; (ii) no adjustment relating to any Tax Return filed by Contributor has been proposed formally or, to the Knowledge of Contributor, informally by any tax authority to Contributor or any representative thereof; and (iii) no claim has ever been made by an authority in a jurisdiction where Contributor does not file Tax Returns that it is or may be subject to taxation by that jurisdiction.

(g) None of the Contributed Assets is “tax exempt use property” within the meaning of Section 168(h) of the Code.

5.7 Intellectual Property.

(a) Section 5.7(a) of the Contributor Disclosure Schedule lists all Registered Intellectual Property Rights within the Contributor Intellectual Property owned by, filed in the name of, or applied for, by Contributor (the “Contributor Registered Intellectual Property Rights”) and, to the Constructive Knowledge of Contributor, lists any proceedings or actions (other than ordinary prosecution activities related to pending patent applications listed in Section 5.7(a) of the Contributor Disclosure Schedule) pending before any court, tribunal (including the United States Patent and Trademark Office (the “PTO”) or equivalent authority anywhere in the world) related to any of Contributor Registered Intellectual Property Rights, which, for the avoidance of doubt, excludes any proceedings or actions where such Contributor Registered Intellectual Property is cited or mentioned but is not otherwise the subject of the proceeding or action.

(b) With respect to the Patents directed to the proteins or polypeptides listed in Section 5.7(b)(1) of the Contributor Disclosure Schedule, or variants of the foregoing, to nucleotides encoding the foregoing, and to methods of use of the foregoing, all necessary registration, maintenance and renewal fees in connection with each such Patent within the Contributor Registered Intellectual Property Rights have been paid and all necessary documents and certificates in connection with such Patent within the Contributor Registered Intellectual Property Rights have been filed with the relevant patent authorities in the United States or foreign jurisdictions, as the case may be, for the purposes of maintaining such Patent within the Contributor Registered Intellectual Property Rights. With respect to other Patents (i.e., Patents directed to matters other than the proteins or polypeptides listed in Section 5.7(b)(1) of the Contributor Disclosure Schedule, or variants of the foregoing, to nucleotides encoding the foregoing, and to methods of use of the foregoing), all necessary registration, maintenance and renewal fees in connection with each such Patent within the Contributor Registered Intellectual Property Rights have been paid and all necessary documents and certificates in connection with such Patent within the Contributor Registered Intellectual Property Rights have been filed with the relevant patent authorities in the United States or foreign jurisdictions, as the case may be, for the purposes of maintaining such Patent within the Contributor Registered Intellectual Property Rights, except with respect to (i) the Patents designated as having being abandoned or inactive on Section 5.7(a) of the Contributor Disclosure Schedule, and (ii) those Patents (if any) listed on Section 5.7(b)(2) of the Contributor Disclosure Schedule which Contributor elects to abandon between the date of execution of this Agreement and the Closing Date. To the Constructive Knowledge of Contributor, there are no actions that must be taken on or before December 31, 2009, including the payments of any registration, maintenance or renewal fees, or the filing of any

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responses to PTO office actions, documents, applications or certificates for the purposes of obtaining, maintaining, perfecting or preserving or renewing any Patent within the Contributor Registered Intellectual Property Rights. Contributor has obtained a valid and enforceable assignment sufficient to irrevocably transfer all rights in all Patents within the Contributor Registered Intellectual Property Rights (including the right to seek past and future damages with respect thereto) to Contributor. To the maximum extent provided for by, and in accordance with, applicable laws and regulations, Contributor has recorded each such assignment with the PTO and, to the Constructive Knowledge of Contributor, with the relevant Governmental Authority outside of the United States, as the case may be. Contributor has not claimed a particular status, including, “Small Business Status,” in the application for any Patent within the Contributor Intellectual Property, which claim of status was at the time made, or which has since become, inaccurate or false.

(c) Contributor has no Constructive Knowledge of any acts or omissions of Contributor that would (i) constitute inequitable conduct, fraud or misrepresentation with respect to any Patent application included within Contributor Registered Intellectual Property, or (ii) render any Patent within the Contributor Registered Intellectual Property invalid or unenforceable in whole or in part. Contributor has not received written notice that any Patent within the Contributor Registered Intellectual Property is invalid or unenforceable in whole or part. No Patent within the Contributor Registered Intellectual Property has been adjudged invalid or unenforceable in whole or part.

(d) Each Patent of Contributor Registered Intellectual Property is free and clear of any Encumbrances. Contributor is the exclusive owner of each Patent listed on Section 5.7(a) of the Contributor Disclosure Schedule and of the Materials listed on Schedules 2.1(a) and 2.1(b)(2) attached hereto, and all such Patents and Materials may be assigned to Company as provided hereunder without Encumbrances.

(e) No biological or other material that are used (or have been used) in or are in possession of Contributor and necessary for the conduct of Contributor’s Business as currently conducted, or as contemplated to be conducted by Contributor, is subject to any material transfer agreement or other agreement restricting, limiting or prohibiting the use, transfer, disclosure or commercial exploitation of such biological or other materials, or of any progeny, derivatives, modifications or improvements thereof (in each case in the manner that Contributor used or intended to use such material in the Business), that would prevent the transfer of such material to Company as contemplated hereunder or prohibit the use of such material by or for Company in the conduct of the Programs as currently conducted by Contributor, or as contemplated to be conducted by Contributor.

(f) All Contributor Intellectual Property to be contributed or assigned to Company (including licenses or sublicenses of Intellectual Property from Third Parties which are Contributor Contracts to be assigned to Company) pursuant to this Agreement, and the license to the Licensed Intellectual Property to be licensed or sublicensed to Company pursuant to the Technology License Agreement, will be fully transferable, alienable or licensable or sublicensable by Company to exploit, use and otherwise practice within the Field without restriction, limitation or other Encumbrance, in each case other than Permitted Encumbrances, and without payment of any kind to any Third Party except as provided under the Technology License Agreement, the

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Astellas Agreement, the Transaction Agreements or any Contributor Contract assigned to Company. Contributor has the full right to grant to Company the licenses (or sublicenses, as applicable) under the Licensed Intellectual Property Controlled by Contributor for the purpose of conducting the 4 Program and Other Programs, all as set forth in, and on the terms and conditions set forth in, the Technology License Agreement.

(g) To the extent that any Contributor Intellectual Property or any Licensed Intellectual Property has been developed or created by a Third Party for or on behalf of Contributor, Contributor has a written agreement with such Third Party with respect thereto and Contributor thereby either (i) has obtained ownership of or (ii) has obtained a license to, in each case sufficient for the conduct of the Business as conducted by Contributor as of or prior to the Closing Date and the Company Business as reasonably anticipated by Contributor to be conducted by Company, to all such Third Party’s Intellectual Property by operation of law, by valid license or by valid assignment.

(h) All existing employees and consultants of Contributor have entered into a valid and binding written agreement with Contributor sufficient to vest title in Contributor of all Contributor Intellectual Property created by such employee or consultant in the scope of his or her services or employment for Contributor. All former employees and consultants of Contributor have entered in a valid and binding written agreement with Contributor sufficient to vest title in Contributor of all Contributor Intellectual Property used in the conduct of (i) the 4 Program and (ii) the Other Programs with respect to the proteins or polypeptides identified in Section 5.7(h) of the Contributor Disclosure Schedule, in each case, created by such employee or consultant in the scope of his or her services or employment for Contributor.

(i) Contributor has taken reasonable steps to protect Contributor’s rights in Trade Secrets of Contributor that is material to Contributor’s conduct of the Business. Without limiting the foregoing, Contributor has, and reasonably enforces, a policy requiring each employee, consultant and contractor to execute a proprietary information, confidentiality and assignment agreement, substantially in the form(s) attached hereto as Section 5.7(i) of the Contributor Disclosure Schedule, and all current and former employees, consultants and contractors of Contributor that generated, or had access to, Trade Secrets of Contributor in connection with the conduct of (i) the 4 Program and (ii) the Other Programs with respect to the proteins or polypeptides identified in Section 5.7(i) of the Contributor Disclosure Schedule, have executed such an agreement.

(j) Except as may be expressly provided under the Contributor Contracts, no Person who has licensed Patents within the Contributor Intellectual Property to Contributor, or who developed or created materials or data (excluding, however, any commercially- or publicly-available materials) for Contributor in connection with the Programs has ownership rights or license rights to improvements made by Contributor in such Intellectual Property.

(k) Other than inbound “shrink-wrap” and similar publicly available commercial binary code end-user licenses and terms and conditions governing the order or supply of commercially- or publicly-available materials, the contracts, licenses and agreements listed in Section 5.7(k) of the Contributor Disclosure Schedule lists all Contracts to which Contributor is a party or third party beneficiary pursuant to which Contributor has (i) obtained, received or is

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granted licenses, options, rights of first refusal, covenants not to enforce or other rights (excluding in-licenses with no applicability within the Field), (ii) provided or granted any licenses, options, rights of first refusal, covenants not to enforce or other rights, or (iii) transferred or assigned ownership of, joint or sole, in each case with respect to any Contributor Intellectual Property or any Licensed Intellectual Property. Contributor is not in material breach of, nor has Contributor materially failed to perform under, any of the foregoing contracts, licenses or agreements which are Contributor Contracts or under which Contributor is granted any license or other rights under Licensed Intellectual Property to be licensed to Company under the Technology License Agreement and, to Contributor’s Knowledge, no other party to any such contract, license or agreement is in breach thereof or has failed to perform thereunder.

(l) To the Knowledge of Contributor, there are no Contracts between Contributor and any other person with respect to Contributor Intellectual Property under which there is any currently-pending dispute regarding the scope of such agreement, or performance under such agreement, including with respect to any payments to be made or received by Contributor thereunder. To the Knowledge of Contributor, there are no Contracts between Contributor and any other person with respect to Licensed Intellectual Property under which there is any currently-pending dispute regarding the rights of the parties thereto within the Field under such agreement or with respect to any breach by Contributor under such agreement.

(m) To Contributor’s Knowledge, no Person is infringing or misappropriating any Contributor Registered Intellectual Property that is owned by Contributor within the Field.

(n) No Contributor Intellectual Property owned by Contributor and, to the Knowledge of Contributor, no Contributor Intellectual Property that is licensed to Contributor by any Third Party, is subject to any action or Proceeding (excluding, however, any Patent prosecution proceedings) or outstanding decree, order, judgment or settlement agreement or stipulation that (i) restricts in any manner the use, transfer or licensing thereof by Contributor (ii) concerns the infringement or misappropriation thereof, or (iii) may affect the validity, use or enforceability of the Contributor Intellectual Property or the ownership of or license to such Contributor Intellectual Property. Contributor has not received any notice regarding any of the foregoing actions or Proceedings or threats thereof. To the Knowledge of Contributor, there is no material basis for any such action or Proceeding or any decree, order, or judgment related to any Contributor Intellectual Property. To the Knowledge of Contributor, there are no Third Parties infringing or misappropriating Enabling Technology as of or prior to the Closing Date relating to Shuffling on a protein or polypeptide identified in Section 5.7(n) of the Contributor Disclosure Schedule.

(o) The Contributor Intellectual Property to be contributed or assigned to Company pursuant to this Agreement or the Transaction Agreements can be contributed or assigned as provided for hereunder or thereunder and the Licensed Intellectual Property to be licensed or sublicensed to Company pursuant to the Technology License Agreement can be licensed or sublicensed in accordance with the Technology License Agreement, and such Contributor Intellectual Property and Licensed Intellectual Property constitute all the Technology and Intellectual Property used by Contributor in and/or, to the extent owned by or (sub)licensed to Contributor, necessary to the conduct of the Business as previously conducted over the past three (3) years by Contributor or the Company Business as reasonably anticipated by Contributor to be

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conducted by Company following the Closing Date, or which resulted from or was generated under the Programs as of or prior to the Closing Date. To the Contributor’s Knowledge, the conduct of the Business or the Company Business as reasonably anticipated by Contributor with respect to the practice of the Enabling Technology, the conduct of the 4 Program, and the proteins or polypeptides listed in Section 5.7(o) of the Contributor Disclosure Schedule, or variants of the foregoing, nucleotides encoding the foregoing, and methods of use of the foregoing does not infringe the Patents of a Third Party that are not licensed to Company under the Technology License Agreement or a Contributor Contract; provided, however, that Contributor makes no representation or warranty pursuant to this sentence with respect to Patents disclosed by Contributor within the three (3) month period prior to the date of this Agreement. Contributor has not received written notice or written claim of infringement from any Third Party alleging that the conduct of the Programs and the operation of the Business as currently conducted by Contributor infringe or misappropriate any Intellectual Property of any Person or violate any right of any Person (including any right to privacy or publicity). Without limiting the foregoing, all Intellectual Property licensed and sublicensed by Contributor to Astellas under the Astellas Agreement immediately prior to the Closing shall remain licensed and sublicensed by Company to Astellas after the Closing to the full extent provided for in the Astellas Agreement prior to Closing, without any diminishment, restriction or limitation of such license and sublicense. Furthermore, all Intellectual Property used by Contributor in the performance of the Astellas Agreement as of or prior to the Closing Date shall be available to the Company after the Closing Date to at least the same extent as available to Contributor as of the Closing Date for purposes of such performance; the Company’s ability to perform its obligations under the Astellas Agreement immediately after the Closing Date shall not be diminished, restricted or limited as compared to Contributor’s ability to perform its obligations under the Astellas Agreement immediately prior to the Closing Date owing to lack of contribution, assignment, license or sublicense by Contributor to Company of Intellectual Property under which Contributor had the right to practice as of or prior to the Closing Date; and the assignment of the Astellas Agreement from Contributor to the Company pursuant to this Agreement shall not result in any increase in the obligations or liabilities of Astellas under the Astellas Agreement.

(p) Except as expressly provided under any one or more of the Contributor Contracts, there are no royalties, fees, honoraria or other payments payable by Contributor to any Person by reason of the ownership, development, use, license, sale or disposition of the Contributor Intellectual Property, other than salaries and sales commissions paid to employees and sales agents in the ordinary course of business.

5.8 Insurance. Section 5.8 of the Contributor Disclosure Schedule sets forth an accurate and complete list of all material insurance policies, self-insurance arrangements and indemnity bonds, currently in effect, that insure the Business and/or the Contributed Assets (collectively, the “Insurance Policies”). Each of the Insurance Policies is legal, valid, binding, and enforceable in accordance with its terms and is in full force and effect and is being assigned hereunder as part of the Contributed Assets and Assumed Liabilities. Contributor is not in breach of any Insurance Policy, and, to the Knowledge of Contributor, no event has occurred which, with notice or the lapse of time, would constitute such a breach, or permit termination, modification, or acceleration, of any of the Insurance Policies. Contributor has not received any written notice of cancellation or non-renewal of any of the Insurance Policies. The consummation of the Transactions will not cause a breach or termination, modification or acceleration of any of the

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Insurance Policies. There is no claim under any of the Insurance Policies that has been improperly filed or as to which any insurer has questioned, disputed or denied liability. Contributor has not received any notice of, nor does Contributor have any Knowledge of any facts that might result in, a material increase in the premium for any of the Insurance Policies.

5.9 Title; All Material Assets; Condition of Assets.

(a) Contributor has, or will have as of the Closing, good and valid title to all of the Contributed Assets free and clear of any Encumbrances except for (i) Encumbrances disclosed on Section 5.9(a) of the Contributor Disclosure Schedule which will be removed and released at or prior to the Closing and (ii) the Permitted Encumbrances. None of the Permitted Encumbrances could reasonably be expected to materially impair the continued use and operation of the Contributed Assets to which it relates as such Contributed Asset is used (or has been used) and operated in the conduct of the Business as of or prior to the Closing Date or the Company Business as reasonably contemplated by Contributor to be conducted by Company after the Closing Date. Contributor has, or will have as of the Closing, full right and power to contribute, convey, assign, transfer and deliver to Company good and valid title to all of the Contributed Assets, free and clear of any and all Encumbrances other than the Permitted Encumbrances. The Contributed Assets are not subject to any preemptive right, right of first refusal, or other similar right or restriction pursuant to any Contract to which the Contributor is a party and any other Contract or other source of which Contributor has knowledge that would adversely affect Company’s rights in the Contributed Assets in any material respect.

(b) The contribution, transfer and assignment of the Contributed Assets as contemplated by this Agreement, together with the licenses and sublicenses granted to Company pursuant to the Technology License Agreement, will give Company possession of or license to, and the right to use, all the assets used by Contributor that are material for conducting the Business as presently conducted, in each case within the Field and except as otherwise provided in the Technology License Agreement or any Contributor Contract assigned to Company; provided, however, that the foregoing clause of this Section 5.9(b) shall not be construed as a representation or warranty of sufficiency of the Contributor Intellectual Property, nor of non-infringement of the intellectual property rights of any Third Party. Upon Closing, Company will acquire exclusive, good and marketable title or license to or a valid leasehold interest in (as the case may be) the Contributed Assets and no restrictions will exist on Contributor’s right to resell, license or sublicense any of the Contributed Assets or Assumed Liabilities or engage in the Company Business, except Permitted Encumbrances. Except for the Contributed Assets and the Licensed Intellectual Property, there are no other assets, properties or rights owned by or licensed to Contributor, including Intellectual Property Rights owned by or licensed to Contributor, that are used (or have been used) by Contributor or its Affiliates and that are material to conduct the Business as of or prior to the Closing Date and material to continued conduct of the Company Business by Company in the manner in which Contributor currently conducts the Business.

(c) The Contributed Assets as a whole (other than Contributor Intellectual Property), to the extent applicable to the Business, (i) are in good operating condition and repair, ordinary wear and tear excepted; (ii) are suitable and adequate for continued use in the ordinary course of business; and (iii) conform to all Legal Requirements applicable to Contributor’s use thereof prior to the Closing Date.

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5.10 Real Property Leases.

(a) Contributor does not currently own any real property. Contributor is in lawful possession of the premises covered by the Real Property Lease. Contributor has made available to Company accurate, correct and complete copies of the Real Property Lease (including all amendments, supplements, modifications and written waivers relating thereto) and copies of existing title insurance policies, title reports and real property surveys in Contributor’s possession, if any, for the real property subject to the Real Property Lease. The Real Property Lease is in full force and effect and is valid and effective in accordance with its terms, except (i) as enforcement may be limited by bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other laws affecting the rights of creditors generally and general equitable principles (whether considered in a proceeding in equity or at law), and (ii) as the remedy of specific performance and injunctive and other forms of equitable relief may be subject to equitable defenses and to the discretion of a court of competent jurisdiction before which any proceeding may be brought, and, to Contributor’s Knowledge, Contributor is not in default thereunder in any respect or as would permit the termination or cancellation of the Real Property Lease. No representation is made in this Section 5.10 with respect to any Intellectual Property.

(b) To Contributor’s Knowledge, there does not exist any actual, threatened or contemplated condemnation or eminent domain proceedings that may materially affect the Leased Real Property.

(c) Except with respect to activities of the Business performed at facilities of Third Party consultants, contractors or licensees of Contributor which are under Contributed Contracts, the Business is conducted only at the Leased Real Property and the Lab Facility and the Office Facility are the only facilities necessary to enable Company to conduct the Company Business in substantially the same manner in which the Business is currently being conducted.

5.11 Employees and Consultants.

(a) [Reserved.]

(b) Except for Contracts listed on Section 5.11(b) of the Contributor Disclosure Schedule or as required by applicable Legal Requirements, no Employee of Contributor has been granted the right to continued employment by Contributor. Contributor has no Knowledge that any Offeree intends to terminate his or her employment or other service-provider relationship with Contributor, nor, as of the date hereof, does Contributor have a present intention to terminate the employment or other service-provider relationship of any such Offeree.

(c) Employee and Contractor Lists. Section 5.11(c) of the Contributor Disclosure Schedule sets forth an accurate, correct and complete list of all:

(i) Employees, which provides their present title or position, present annual base compensation, present bonus and commission eligibility, accrued but unused vacation and other paid leave, and years of service with Contributor as of the date hereof,

(ii) individuals who are currently performing services for Contributor related to the Business who are classified as “consultants” or “independent contractors.”

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(d) No Employee is eligible for payments in connection with the Transactions that would constitute “parachute payments” under Section 280G of the Code.

(e) Compliance with Legal Requirements. Contributor has complied with all Legal Requirements in all material respects related to the employment of the Employees, including provisions related to wages, hours, leaves of absence, equal opportunity, occupational health and safety, workers’ compensation, severance, employee handbooks or manuals, collective bargaining and the payment of social security and other Taxes.

(f) Unions. Contributor is not a party to any collective bargaining agreement with respect to the Employees, and none of the Employees are represented by any labor union or other similar labor-relations entity or organization. There is no labor union organizing or election activity pending or, to the Knowledge of Contributor, threatened with respect to the Employees. To the Knowledge of Contributor, Contributor has not suffered or sustained any work stoppage in connection with any labor union or other similar labor-relations entity or organization, and no such work stoppage is threatened.

5.12 Contributor Benefit Plans.

(a) Section 5.12(a) of the Contributor Disclosure Schedule sets forth an accurate, correct and complete list of each of the Contributor Benefit Plans. With respect to each Contributor Benefit Plan, Contributor has provided or made available to Astellas true, current, complete and correct copies, to the extent applicable, of (i) each Contributor Benefit Plan (or, in the case of any unwritten Contributor Benefit Plan, an accurate description thereof), (ii) the most recent annual report on Form 5500 filed with the Internal Revenue Service with respect to each such Contributor Benefit Plan (if any such report was required), (iii) each trust agreement and group annuity contract relating to each such applicable Contributor Benefit Plan, (iv) the most recent summary plan description together with the summary or summaries of material modifications thereto, if any and (v) with respect to each such applicable Contributor Benefit Plan, the most recent financial statements (if any) that are required to be prepared pursuant to applicable Legal Requirements.

(b) Contributor has maintained, administered and funded each Contributor Benefit Plan, in accordance with its terms and all applicable laws. Neither Contributor nor any Member of the Controlled Group maintains or contributes to, or has ever had an obligation to maintain or contribute to, any Defined Benefit Plan or Multiemployer Plan. Nothing contained in any of the Contributor Benefit Plans, other than any Contributor Benefit Plan in which Company agrees to participate, will obligate Company to provide any benefits to employees, former employees or beneficiaries of employees or former employees, or to make any contributions to any employee benefit plans from and after the Closing.

(c) All Contributor Benefit Plans intended to be tax-qualified for United States Federal income tax purposes have been the subject of determination letters from the Internal Revenue Service to the effect that such Contributor Benefit Plans are qualified and exempt from Federal income taxes under Sections 401(a) and 501(a), respectively, of the Code, and no such determination letter has been revoked nor, to the Knowledge of Contributor, has revocation been threatened, nor has any such Contributor Benefit Plans been amended since the date of its most recent determination letter or application therefor in any respect that would reasonably be expected to adversely affect its qualification.

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(d) With respect to each Contributor Benefit Plan: (i) Contributor is not subject to any liability under Sections 4975 through 4980B of the Code or Title I of ERISA, (ii) Contributor has complied with all applicable health care continuation requirements in Section 4980B of the Code and in Part 6 of Title I of ERISA, and (iii) no “Prohibited Transaction,” within the meaning of Section 4975 of the Code or Sections 406 or 407 of ERISA and not otherwise exempt under Section 408 of ERISA, has occurred with respect to any Contributor Benefit Plan with respect to which Company would or could reasonably be expected to be subject to any Liability.

(e) No material Contributor Benefit Plan provides health benefits (whether or not insured) with respect to employees or former employees (or any of their beneficiaries) of the Contributor or any of its Subsidiaries after retirement or other termination of service (other than coverage or benefits (i) required to be provided under Part 6 of Title I of ERISA or any other similar applicable Law or (ii) the full cost of which is borne by the employee or former employee (or any of their beneficiaries)).

(f) No material action, suit or claim (excluding claims for benefits incurred in the ordinary course) has been brought or is pending or, to the Knowledge of Contributor, has been threatened in writing against or with respect to any Contributor Benefit Plan or the assets or any fiduciary thereof (in that person’s capacity as a fiduciary of such Contributor Benefit Plan). There are no audits, inquiries or proceedings pending or, to the Knowledge of Contributor, threatened in writing by the Internal Revenue Service, the Department of Labor, or other Governmental Authority with respect to any Contributor Benefit Plan.

(g) The execution of this Agreement and the consummation of the transactions contemplated by this Agreement or other Transaction Agreements (alone or together with any other event which, standing alone, would not by itself trigger such entitlement or acceleration) will not (i) entitle any Offeree to any payment, forgiveness of indebtedness, vesting, distribution, or increase in benefits under or with respect to any Contributor Benefit Plan, (ii) otherwise trigger any acceleration (of vesting or payment of benefits or otherwise) affecting any Offeree under or with respect to any Contributor Benefit Plan, or (iii) trigger any obligation to fund any Contributor Benefit Plan.

(h) No Offeree is reasonably expected to incur additional tax under Section 409A(a)(1)(B) of the Code as a result of participation in any Contributor Benefit Plan. Contributor is not a party to, or otherwise obligated under, any contract, agreement, plan or arrangement that provides for the gross-up of taxes imposed by Section 409A(a)(1)(B) of the Code with respect to Offerees.

5.13 Material Contracts.

(a) Section 5.13 of the Contributor Disclosure Schedule provides a true and complete list of each Contract in one or more of the following categories, to which Contributor is party and which relate primarily to (x) the operation of the Business, or (y) any of the Contributed Assets (collectively, the “Material Contracts”):

(i) All Real Property Leases, Personal Property Leases, Insurance Policies, Contracts required to be listed on Section 5.7(k) of the Contributor Disclosure Schedule and Governmental Approvals;

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(ii) Any Contract for capital expenditures or for the purchase of goods or services such as would require Company to make payment(s) in excess of $100,000 with respect to any twelve (12) month period following the Closing (excluding any Contributor Benefit Plan or other employment-related Contracts);

(iii) [Reserved];

(iv) Any Contract involving financing or borrowing of money, or evidencing indebtedness for borrowed money, any obligation for the deferred purchase price of property or guaranteeing in any way any Contract in connection with any Person, in each case such as would require Company to make payment(s) in excess of $100,000 with respect to any twelve (12) month period following the Closing (excluding normal trade payables);

(v) Any joint venture, partnership, cooperative arrangement or any other Contract involving a sharing of profits (except for the Transaction Agreements and the Astellas Agreement);

(vi) Any material Contract with any Governmental Authority;

(vii) Any Contract with respect to the discharge, storage or removal of effluent, waste or pollutants;

(viii) Any Contract relating to any license or royalty arrangement that provides for noncontingent annual payments by Contributor in excess of $100,000, except any such noncontingent payment(s) such as would not exceed $100,000 with respect to any twelve (12) month period following the Closing;

(ix) Any power of attorney, proxy or similar instrument;

(x) Any Contract with any Affiliate of Contributor (other than any Contributor Benefit Plan or other employment-related Contracts);

(xi) Any Contract for the manufacture, service or maintenance of any product of the Business including CROs, research agreements and finding agreements;

(xii) Any Contract for the purchase or sale of any amount of assets other than in the ordinary course of business or for the option or preferential rights to purchase or sell any material amount of assets other than in the ordinary course of business;

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(xiii) Any Contract to indemnify any Person or to share in or contribute to the liability of any Person other than standard non-material form indemnity agreements that have been entered into in the ordinary course of business;

(xiv) Any Contract containing covenants not to compete which materially restrict the Contributor from competing in any line of business or with any Person in any geographical area;

(xv) Any Contract related to the acquisition of a business or the equity of any other Entity to the extent that it relates to the Business;

(xvi) Any other Contract (other than any Contributor Benefit Plan or other employment-related Contracts) (A) such as would require Company to make payment(s) in excess of $100,000 with respect to any twelve (12) month period following the Closing; and (B) is not terminable without payment or penalty on thirty (30) days (or less) notice.

(xvii) Any other Contract (other than any Contributor Benefit Plan or other employment-related Contracts) that involves future payments, performance of services or delivery of goods or materials to or by Contributor such as would require the Company to make payment(s) in excess of $100,000 with respect to any twelve (12) month period following the Closing;

(xviii) Any Contract related to tools, machinery, equipment and personal property with ongoing performance obligations that is not already identified under clauses (ii), (xvi) or (xvii) and exceeds the dollar thresholds set forth therein;

(xix) Any Contact within or needed in the ordinary course of the Business not already identified in clauses (i) through (xviii) which would require Company to make non-contingent payment(s) in excess of $100,000 with respect to any twelve (12) month period following the Closing (other than any Contributor Benefit Plan or any other employment-related Contracts); and

(xx) Any proposed arrangement of a type that, if entered into, would be a Contract described in any of (i) through (xviii) above.

(b) Contributor has made available to Company accurate, correct and complete copies of all Material Contracts (or written summaries of the material terms thereof, if not in writing), including all material amendments, supplements, modifications and waivers thereof. All Material Contracts are in writing.

(c) Each Contributor Contract is currently valid and in full force and effect, and, is enforceable by Contributor in accordance with its terms, except (i) as enforcement may be limited by bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other laws affecting the rights of creditors generally and general equitable principles (whether considered in a proceeding in equity or at law), and (ii) as the remedy of specific performance and injunctive and other forms of equitable relief may be subject to equitable defenses and to the discretion of a court of competent jurisdiction before which any proceeding may be brought.

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(d) Contributor is not in material default, and no party has provided written notice to Contributor that it is in material default, under any Contributor Contract. No event has occurred that might (with or without notice or lapse of time) (i) result in any material violation or breach, by Contributor, of any of the provisions of any Contributor Contract; (ii) give any Person other than Contributor the right to declare a default or exercise any remedy under any Contributor Contract; (iii) give any Person the right to accelerate the maturity or performance of any Contributor Contract or to cancel, terminate or modify any Contributor Contract; or (iv) otherwise have a Material Adverse Effect on Contributor in connection with any Contributor Contract. Contributor has not waived any material rights which relate to the Business or Contributed Assets of the agreements described in Section 5.13(a)(i) through 5.13(a)(xx) hereof.

(e) To the Knowledge of Contributor, each Person against which Contributor has or may acquire any rights under any Contributor Contract is (i) not in material breach of, and has not threatened in writing to be in breach of, the Contributor Contract to which such Person is a party; (ii) solvent; and (iii) able to satisfy such Person’s material obligations and Liabilities to Contributor.

(f) The performance of the Contributor Contracts will not result in any violation of or failure by Contributor to comply with any Legal Requirement.

5.14 Restrictions on Business Activities. There is no agreement (not to compete or otherwise), commitment, judgment, injunction, order or decree to which Contributor is a party or, to Contributor’s Knowledge, which is otherwise binding upon Contributor which has the effect of prohibiting or restricting any Company’s use or exploitation of any Contributed Asset in the manner in which it is currently used or exploited (or has been used or exploited in the past), except as would not have a Material Adverse Effect on the Company. Without limiting the foregoing, Contributor has not entered into any agreement under which Contributor is restricted from selling, licensing or otherwise distributing any of its products for use in the Field to or providing services in the Field to, customers or any class of customers, in any geographic area, or in any segment of the market within the Field in connection with the Business or the Contributed Assets.

5.15 Compliance with Laws; Governmental Approvals.

(a) Contributor is now, and during the past five years has been, in full compliance with each Legal Requirement applicable to the Business or the Contributed Assets, and, to the Knowledge of Contributor, no event has occurred, and no condition or circumstance exists, that might (with or without notice or lapse of time) constitute, or result directly or indirectly in, a default under, a breach or violation of, or a failure comply with, any such Legal Requirement; except for any such non-compliance, failure, breach or violation which would not have a Material Adverse Effect on the Company. Contributor has not received any written notice from any Third Party regarding any actual, alleged or potential material violation of any such Legal Requirement applicable to the Business or the Contributed Assets except for any of the foregoing which would not have a Material Adverse Effect on the Company.

(b) Contributor has all Governmental Approvals that are necessary in connection with Contributor’s occupation and use of the Facility, the ownership and use of the Business or the Contributed Assets (collectively, the “Business Governmental Approvals”).

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Contributor has made all filings with, and given all notifications to, all Government Authorities with respect to the business as required by all applicable Legal Requirements except to the extent that the failure to make any such filings would not have a Material Adverse Effect on the Company. Each Business Governmental Approval is valid and in full force and effect, and there is not pending or, to the Knowledge of Contributor, threatened any Proceeding which could result in the suspension, termination, revocation, cancellation, limitation or impairment of any Business Governmental Approval. No material violations have been recorded in respect of any Business Governmental Approvals, and to the Knowledge of the Contributor, there are no meritorious basis therefor. No fines or penalties are due and payable in respect of any Business Governmental Approval or any violation thereof.

(c) Contributor has made available to Company accurate and complete copies of all of the Business Governmental Approvals, including all renewals thereof and all amendments thereto.

5.16 Proceedings and Orders.

(a) As of the date hereof, there is no material Proceeding pending or, to the Knowledge of Contributor, threatened in writing against or affecting the Business or the Contributed Assets or Contributor’s rights relating thereto. To Contributor’s Knowledge, no event has occurred, and no condition or circumstance exists, that might directly or indirectly give rise to or serve as a basis for the commencement of any such Proceeding. Contributor has made available to Company true, accurate and complete copies of all material pleadings, material correspondence with Third Parties and other material, non-privileged documents relating to any such Proceeding that are either (i) in its possession or (ii) reasonably accessible to it and of which it is has Knowledge. No insurance company has asserted in writing that any such Proceeding is not covered by the applicable policy of Contributor related thereto.

(b) As of the date hereof, neither Contributor, the Employees (in their capacities as employees or representatives of Contributor) nor any of the Contributed Assets or the Business, nor Contributor’s rights relating to any of the foregoing, is subject to any material Order.

5.17 Litigation. There is no Proceeding with respect to Contributor relating to the Business or the Contributed Assets (including any Proceeding involving the prior employment of any of Contributor’s employees relating to the Business or the Contributed Assets, their services provided in connection with such Business, or any information or techniques allegedly proprietary to any of their former employers, or their obligations under any agreements with prior employers) pending or to Contributor’s Knowledge, currently threatened (i) against Contributor or any officer, director or Employee of Contributor (in their capacities as such); or (ii) that questions the validity of the Transaction Agreements or the right of Contributor to enter into any of them, or to consummate the Transactions except those which would not have a Material Adverse Effect. Neither Contributor nor, to Contributor’s Knowledge, any of its officers, directors or Employees (in their capacities as such) is a party or is named as subject to the provisions of any order, writ, injunction, judgment, or decree of any court or government agency or instrumentality (in the case of officers, directors or Employees, such as would materially affect Contributor) relating to the Business or the Contributed Assets. There is no Proceeding with respect to Contributor by Contributor pending or which Contributor intends to initiate relating to the Business or the Contributed Assets except those which would not have a Material Adverse Effect.

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5.18 Environmental Matters.

(a) To Contributor’s Knowledge, the Business has been and is being conducted, and the Leased Real Property and the PP&E have been and are being operated, in compliance in all material respects with all Environmental Laws. The Contributor has not received, nor has Knowledge of the issuance of, any written notice of violation alleging any material non-compliance by Contributor, the Leased Real Property or the PP&E with any Environmental Law.

(b) The Contributor has obtained and currently maintains all Environmental Permits necessary for the conduct of the Business as presently conducted. To Contributor’s Knowledge, the Business has been and is being conducted, and the Leased Real Property and the PP&E have been and are being operated, in compliance in all material respects with all such Environmental Permits, and all such Environmental Permits remain in full force and effect. Contributor has not received any written notice that the Business lacks any such Environmental Permit and, to Contributor’s Knowledge, no such notice is threatened.

(c) There is no pending Environmental Claim arising out of the Business or the Contributor’s occupation, use or operation of the Leased Real Property or the PP&E, and, to Contributor’s Knowledge, no such Environmental Claim is threatened, including any Environmental Claims with respect to third party disposal sites.

(d) To Contributor’s Knowledge, there have been no past and are no present activities or practices of Contributor in violation of Environmental Law, including a Release of a Regulated Substance into or onto the Leased Real Property or any Third Party disposal sites which requires or is reasonably anticipated to require Remedial Action by the Contributor, or which would result in material liability to Contributor.

(e) Contributor has not operated any (i) underground storage tanks or surface tanks, dikes or impoundments, or (ii) equipment containing polychlorinated biphenyls on the Leased Real Property.

(f) Other than any Real Property Leases, Governmental Approvals, Environmental Permits, or contracts with third parties for emergency response to, and the collection, transportation and disposal of Regulated Substances, which have been made available to Company, there are no Contributor Contracts relating to the Business or Contributed Assets which would require the Contributor to indemnify, reimburse, defend, hold harmless or release any Third Party from any liability or obligation under or pursuant to any Environmental Law or relating to any Remedial Action.

(g) The Contributor has made available to Company all material written environmental assessments, audits, and environmental surveys, investigations or soil or groundwater sampling reports prepared by Contributor or for Contributor and provided to Contributor by Third Parties, relating to the Environment at the Facility or any Release or presence of or exposure to any Regulated Substances at the Facility in violation of Environmental Law or in a manner which would reasonably be expected to result in liability to Contributor.

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(h) The Parties agree that the only representations and warranties that relate to environmental matters, including Environmental Laws, Regulated Substances, Environmental Permits, and Environmental Claims are contained within Section 5.18 hereof.

5.19 Bulk Sales. There are no “bulk sales” Legal Requirements applicable to the contribution of the Contributed Assets pursuant to this Agreement.

5.20 No Other Agreement. Other than for sales of assets in the ordinary course of business, neither Contributor, nor any of its Representatives, has entered into any Contract with respect to the sale or other disposition of the Contributed Assets except as set forth in this Agreement.

5.21 Power of Attorney. There are no outstanding powers of attorney, proxy or similar instrument executed on behalf of Contributor relating to the Business or the Contributed Assets.

5.22 Export Controls; Foreign Corrupt Practices Act. To the extent relevant to the Business or the Contributed Assets, Contributor has at all times been in compliance with (a) all applicable U.S. Legal Requirements relating to export control requirements and U.S. trade embargoes (Cuba, Sudan, North Korea, Syria and Iran), (b) the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations promulgated thereunder, except in either case for any instance of non-compliance that would not reasonably be expected to result in a Material Adverse Effect with respect to Contributor.

5.23 Antiboycott Laws. To the extent relevant to the Business or the Contributed Assets, Contributor has not violated the antiboycott prohibitions contained in 50 U.S.C. § 2401 et seq. or taken any action that can be penalized under Section 999 of the Code, except in either case for any violation or action that would not reasonably be expected to result in a Material Adverse Effect with respect to Contributor.

ARTICLE 6

REPRESENTATIONS AND WARRANTIES OF COMPANY

Company hereby represents and warrants to Contributor that, as of the date hereof:

6.1 Organization and Qualification. Company is a limited liability company duly organized, validly existing and in good standing under the laws of the jurisdiction of its formation, and has all requisite power and authority to own, lease and operate its properties and to carry on its business as now being conducted.

6.2 Authority. Company has all necessary power and authority to execute and deliver this Agreement and the other Transaction Agreements and to perform its obligations hereunder. The execution and delivery of this Agreement and the other Transaction Agreements

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and the consummation by Company of the Transactions have been duly and validly authorized by all requisite corporate action on the part of Company and its directors and officers and no other corporate proceedings on the part of Company are necessary to authorize this Agreement or the other Transaction Agreements or to consummate the Transactions. This Agreement and the other Transaction Agreements (other than the Bridge Loan Agreement) have been duly and validly executed and delivered by Company. This Agreement and the other Transaction Agreements constitute the legal, valid and binding obligations of Company, enforceable against Company in accordance with their respective terms, except as may be limited by bankruptcy, insolvency, reorganization, moratorium and other similar laws and equitable principles related to or limiting creditors’ rights generally and, by the availability of equitable remedies and defenses and, to the extent the indemnification provisions contained in the Investors’ Rights Agreement may further be limited by applicable laws and principles of public policy.

ARTICLE 7

MISCELLANEOUS PROVISIONS

7.1 Governing Law. This Agreement and any dispute arising from the performance or breach hereof shall be governed by and construed and enforced in accordance with the substantive Laws of the State of Delaware, without reference to conflicts of Laws principles that would result in laws of a jurisdiction other then the State of Delaware governing. Notwithstanding the above, any dispute regarding validity or enforceability of any patent shall be governed by the patent laws of the jurisdiction in which such patent was issued solely for the purpose of resolution of the dispute as to validity and enforceability.

7.2 Assignment. Except as provided in this Section 7.2, this Agreement shall not be assignable or otherwise transferred, in whole or in part, by any Party to any Third Party without the written consent of the other Parties, provided that this Agreement may without requiring the consent of any other Party be assigned, transferred, delegated or sublicensed to (i) an entity that acquires all or substantially all of the business or assets of such Party, whether by merger, reorganization, acquisition, asset sale or otherwise, or (ii) a Related Entity of such Party, (including, for the avoidance of doubt and without limitation, a liquidating trust or similar entity), in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement, the Joint Venture Agreement and the Purchase Agreement. Except as expressly provided in this Section 7.2, any attempted assignment or transfer of this Agreement shall be null and void. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the Parties.

7.3 Notices. Any notice, request, delivery, approval or consent required or permitted to be given under this Agreement shall be in English language, in writing, shall specifically refer to this Agreement and shall be deemed to have been sufficiently given if delivered in person, transmitted as a PDF attachment to an email (receipt verified)or by express courier service (signature required) or five (5) Business Days after it was sent by registered letter, return receipt requested (or its equivalent), provided that no postal strike or other disruption is then in effect or comes into effect within two (2) Business Days after such mailing, to the Party to which it is directed at its address or email address shown below or such other address or email address as such Party will have last given by notice to the other Party.

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If to Contributor,
addressed to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
with copy to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: General Counsel
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
and a copy to:	Wilson Sonsini Goodrich & Rosati
	Professional Corporation
	650 Page Mill Road
	Palo Alto, CA 94304-1050
	USA
	Attention: Tony Jeffries
	Telephone: (650) 493-9300
	Email address: tjeffries@wsgr.com
If to Company, addressed to:	Perseid Therapeutics LLC
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
with a copy to:	3-11, Nihonbashi-Honcho 2-chome
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Business Development
	Telephone: (813) 3244-2500
	Email address: masaki.doi@jp.astellas.com

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with a copy to:	Astellas Pharma Inc.
	3-11, Nihonbashi-Honcho 2-chome
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Legal
	Telephone: (813) 3244-3231
	Email address: kazunori.okimura@jp.astellas.com
with a copy to:	Morrison & Foerster LLP 1290 Avenue of the Americas New York, NY 10104
	Attention: Michael O. Braun, Esq. Telephone: (212) 468-8000 Email address: mbraun@mofo.com

7.4 Waiver. No Party may waive or release any of its rights or interests in this Agreement except in writing. The failure of either Party to assert a right hereunder or to insist upon compliance with any term or condition of this Agreement shall not constitute a waiver of that right or excuse a similar subsequent failure to perform any such term or condition. No waiver by either Party of any condition or term in any one or more instances shall be construed as a continuing waiver of such condition or term or of another condition or term.

7.5 Waiver of Jury Trial. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING (WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATED TO THIS AGREEMENT.

7.6 Severability. If any provision hereof is held invalid, illegal or unenforceable by any court of competent jurisdiction from which no appeal can be or is taken, the Parties shall negotiate in good faith a valid, legal and enforceable substitute provision that most nearly reflects the original intent of the Parties and all other provisions hereof shall remain in full force and effect in such jurisdiction and shall be liberally construed in order to carry out the intentions of the Parties as nearly as may be possible. Such invalidity, illegality or unenforceability shall not affect the validity, legality or enforceability of such provision in any other jurisdiction.

7.7 Entire Agreement/Modification. The Transaction Agreements (including Exhibits and Schedules hereto and thereto) set forth all the covenants, promises, agreements, warranties, representations, conditions and understandings between the Parties with respect to the subject matter hereof and thereof, and supersede all prior agreements and understandings between the Parties with respect to such subject matter. Subject to Section 8.4 of the Joint Venture Agreement, no subsequent alteration, amendment, change or addition to this Agreement shall be binding upon the Parties unless reduced to writing and signed by the respective authorized officers of each of the Parties.

7.8 Relationship of the Parties. The Parties agree that this Agreement does not, is not intended to, and shall not be construed to, establish an agency, partnership or any other relationship. Except as may be specifically provided herein, neither Party shall have any right, power or authority, nor shall they represent themselves as having any authority to assume, create or incur any expense, liability or obligation, express or implied, on behalf of the other Party, or otherwise act as an agent for the other Party for any purpose.

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7.9 Force Majeure. Except with respect to payment of money, no Party shall be liable or responsible to any other Party nor be deemed to have defaulted under or breached this Agreement for failure or delay in fulfillment or the performance of any of its obligations under this Agreement for the time and to the extent such failure or delay is caused by or results from fire, earthquake, tornado, embargo, prohibition or intervention, riot, civil commotion, war, act of war (whether war be declared or not), insurrection, terrorist act, strike, flood, governmental act or restriction (beyond the reasonably control of the respective Party), act of God, or other cause that is beyond the reasonable control and not caused by the negligence or misconduct of the affected Party. Any Party affected by such force majeure will provide the other Party with full particulars thereof as soon as it becomes aware of the same (including its best estimate of the likely extent and duration of the interference with its activities), and will use commercially reasonable efforts to overcome the difficulties created thereby and to resume performance of its obligations as soon as practicable. If the performance of any such obligation under this Agreement is delayed owing to such a force majeure for any continuous period of more than one hundred eighty (180) days, the Parties hereto will consult with respect to an equitable solution, including the possibility of the mutual termination of this Agreement.

7.10 Third Party Beneficiaries. Without limiting any rights or remedies of Astellas under the Joint Venture Agreement, all rights, benefits and remedies under this Agreement are solely intended for the benefit of Contributor and Company and, without limiting any rights or remedies of Astellas under the Joint Venture Agreement, no Third Party shall have any rights whatsoever to (a) enforce any obligation contained in this Agreement (b) seek a benefit or remedy for any breach of this Agreement, or (c) take any other action relating to this Agreement under any legal theory, including but not limited to, actions in contract, tort (including but not limited to negligence, gross negligence and strict liability), or as a defense, setoff or counterclaim to any action or claim brought or made by the Parties.

7.11 Expenses. Whether or not the Transactions contemplated herein are consummated, except as otherwise provided herein, all fees and expenses incurred in connection with this Agreement and the Transactions including, but not limited to, all legal, accounting, financial, advisory, consulting and all other fees and expenses of Third Parties incurred by a Party in connection with the negotiation and effectuation of the terms and conditions of this Agreement and the Transactions shall be the obligation of the respective Party incurring such fees and expenses.

7.12 Further Assurances. At any time or from time-to-time on and after the date hereof, any Party shall at the request of the other Party to the extent permitted by applicable Legal Requirements (a) deliver to the requesting Party such records, data or other documents consistent with the provisions of this Agreement, (b) execute, and deliver or cause to be delivered, all such consents, documents or further instruments of assignment, transfer or license consistent with the provisions of this Agreement, and (c) take or cause to be taken all such actions, as the requesting Party may reasonably deem necessary or desirable in order for the requesting Party to obtain the full benefits of this Agreement and the transactions contemplated hereby. Furthermore, upon Company’s request, Contributor shall reasonably cooperate to enforce provisions for the

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assignment of Intellectual Property to Contributor under any employment agreement, consulting agreement or other Contract not assigned to Company hereunder which provides for the assignment to Contributor of any Intellectual Property which is part of the Contributed Assets to be assigned to Company hereunder to the extent reasonably necessary for Company to secure, protect, enforce or assign to Company any such Intellectual Property, at Company’s expense.

7.13 Counterparts; Facsimile. This Agreement may be executed and delivered by facsimile or PDF signature and in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

7.14 Interpretation. Unless otherwise indicated herein, with respect to any reference made in this Agreement to a Section (or Article, Subsection, Paragraph, Subparagraph or Clause), Exhibit or Schedule, such reference shall be to a section (or article, subsection, paragraph, subparagraph or clause) of, or an exhibit or schedule to, this Agreement. The table of contents and any article, section, subsection, paragraph or subparagraph headings contained in this Agreement and the recitals at the beginning of this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “but (is/are) not limited to.” Words used herein, regardless of the number and gender specifically used, shall be deemed and construed to include any other number, singular or plural, and any other gender, masculine, feminine or neuter, as the context indicates is appropriate. Where specific language is used to clarify or illustrate by example a general statement contained herein, such specific language shall not be deemed to modify, limit or restrict the construction of the general statement which is being clarified or illustrated. Unless otherwise specified, any reference to a time or date shall be with reference to the time or date, as the case may be, in Wilmington, Delaware.

7.15 Construction. The construction of this Agreement shall not take into consideration the Party who drafted or whose representative drafted any portion of this Agreement, and no canon of construction shall be applied that resolves ambiguities against the drafter of a document. Each Party acknowledges that: (a) it has read this Agreement; (b) it has been represented in the preparation, negotiation and execution of this Agreement by legal counsel of its own choice or has voluntarily declined to seek such counsel; and (c) it understands the terms and consequences of this Agreement and is fully aware of the legal and binding effect of this Agreement.

7.16 Provisional Relief; Specific Performance. Nothing in this Agreement shall limit the right of any Party to seek to obtain in any court of competent jurisdiction any interim relief or provisional remedy, including injunctive relief (but not, for the avoidance of doubt, any monetary damages or monetary relief under any equitable theory), pending resolution under Article 10 of the Joint Venture Agreement, as applicable, that may be necessary to protect the rights or property of that Party. Seeking or obtaining such equitable or interim relief or provisional remedy in a court shall not be deemed a waiver of the agreement to arbitrate. For clarity, any such interim relief or provisional remedies shall be cumulative and not exclusive and are in addition to any other remedies that any Party may have under this Agreement or applicable Legal Requirement.

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7.17 Confidentiality; Publicity. The Parties acknowledge that the transaction described herein and the terms of this Agreement are subject to the requirements of Section 8.7 of the Joint Venture Agreement.

7.18 Indemnification; Sole Remedy; Dispute Resolution. The Parties acknowledge and agree that their respective liabilities and obligations for breaches of the representations, warranties and covenants contained in this Agreement are governed by and subject to the terms and conditions of Article 9 of the Joint Venture Agreement. Further, the parties expressly acknowledge and agree that the remedy for breaches of representations, warranties and covenants under the Joint Venture Agreement are addressed solely in Article 9 of the Joint Venture Agreement, and any incorporation by reference of such representations, warranties and covenants in this Agreement shall not give rise to claims under this Agreement. For the avoidance of doubt, nothing in this Agreement nor any other Transaction Agreement is intended to nor shall be deemed to grant any party more than a single monetary damages remedy or recovery, in any given instance, for any other party’s breach of an individual representation or warranty with respect to any specific given event, fact or circumstance, even though such representation or warranty may be present in more than one Transaction Agreement or claimed by its incorporation by reference to be confirmed in more than one Transaction Agreement. Any dispute arising out of or in connection with this Agreement shall be submitted for resolution in accordance with Article 10 of the Joint Venture Agreement. The Parties shall be entitled to injunctive relief or specific performance to the extent provided for in Section 10.4 of the Joint Venture Agreement.

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IN WITNESS WHEREOF, each of the Parties has caused this Asset Contribution Agreement to be executed on its behalf by their respective officers thereunto duly authorized all as of the date first written above.

MAXYGEN, INC.:
By:	/s/ Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

Signature Page to Asset Contribution Agreement

IN WITNESS WHEREOF, each of the Parties has caused this Asset Contribution Agreement to be executed on its behalf by their respective officers thereunto duly authorized all as of the date first written above.

PERSEID THERAPEUTICS LLC:
By:	/s/ Grant Yonehiro
Name:	Grant Yonehiro
Title:	CEO & President

Signature Page to Asset Contribution Agreement

EX-2.1.2

EXHIBIT 2.1.2

TECHNOLOGY LICENSE AGREEMENT

This Technology License Agreement (this “Agreement”) is entered into as of the 18^th day of September, 2009 (“Effective Date”) by and between Maxygen, Inc., a Delaware corporation with its principal place of business at 515 Galveston Drive, Redwood City, California 94063 (“Maxygen”), and Perseid Therapeutics LLC, a Delaware limited liability company with its principal place of business at 515 Galveston Drive, Redwood City, California 94063 (“CPC”). Maxygen and CPC are each referred to herein by name or, individually, as a “Party” or, collectively, as the “Parties.”

BACKGROUND

A. Maxygen owns or possesses certain right, title and interest in Enabling Technology, Software, In-Licensed Project-Specific Technology, RR Technology and CMVP Technology, and related Patents and Know-How (all as defined below), which may have potential usefulness in the research, development, manufacture or commercialization of protein pharmaceutical products;

B. Concurrently with the execution of this Agreement, Maxygen and CPC have executed Asset Contribution Agreement between Maxygen and CPC (the “Asset Contribution Agreement”) pursuant to which CPC will acquire certain assets of Maxygen related to the research, development, manufacture or commercialization of protein pharmaceutical products;

C. CPC desires to obtain certain licenses with respect to the Enabling Technology, Software, In-Licensed Project-Specific Technology, RR Technology and CMVP Technology, and Maxygen is willing to grant such licenses, all on the terms and conditions set forth herein;

NOW, THEREFORE, in consideration of the premises and mutual covenants herein below, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties agree as follows:

ARTICLE 1

DEFINITIONS

The following capitalized terms shall have the corresponding meanings as used in this Agreement:

1.1 “4 Program” shall have the meaning provided in the Asset Contribution Agreement.

1.2 “Accounting Standards” means generally accepted accounting principles applicable internationally or in a particular country (e.g., International Accounting Standards, Japanese Accounting Standards, U.S. Accounting Standards), as consistently applied by or on behalf of the relevant Party.

1.3 “Adjuvant” means a nucleic acid, protein or polypeptide that, when administered in conjunction with one or more Antigens (simultaneously or in a phased manner), induces in a human or animal recipient an improved Immune Response to the one or more Antigens; in each case,

regardless of the formulation of such nucleic acid, protein or polypeptide (e.g., whether containing purified nucleic acid(s), protein(s) or polypeptide(s), a mixture of nucleic acid(s), protein(s) or polypeptide(s) or displayed on the surface of a cell, spore, virus or other delivery vehicle) or the mode of its delivery (e.g., via injection, ingestion, inhalation or ballistic device). For purposes of clarity, a therapeutic protein, polypeptide or nucleic acid that creates an Antigen Specific Response per se to such therapeutic protein, polypeptide or nucleic acid (or protein or polypeptide encoded by such nucleic acid) is not an Adjuvant for purposes of this Agreement. (“Antigen,” “Antigen-Specific Response,” and “Immune Response” are defined in Sections 1.48, 1.48.1, and 1.48.2 below.)

1.4 “Affiliate” means any corporation or other business entity that controls, is controlled by, or is under common control with a Party, for so long as such control exists. A corporation or other entity shall be regarded as in “control” of another corporation or entity if it owns or directly or indirectly controls at least fifty percent (50%) of the outstanding shares or other voting rights of the other corporation or entity having the right to elect directors or such lesser percentage that is the maximum permitted to be owned by a foreign entity in those jurisdictions where majority ownership by foreign entities is prohibited, or (i) in the absence of the ownership of at least fifty percent (50%) of the outstanding shares or other voting rights of a corporation, or (ii) in the case of a non-corporate business entity, if it possesses, directly or indirectly, the power to direct or cause the direction of the management and policies of the corporation or non-corporate business entity, as applicable, whether through the ownership or control of voting securities, by contract or otherwise. Notwithstanding a Party’s ownership interest in, or control over, the other Party, a Party hereunder shall not be deemed an Affiliate of the other Party under this Agreement. Furthermore, notwithstanding Astellas’ ownership interest in, or control over, CPC, CPC shall not be deemed an Affiliate of Astellas, nor vice versa, under this Agreement unless, and until such time as, Astellas acquires one hundred percent (100%) ownership of CPC through exercise of its Buy-Out Option or otherwise.

1.5 “Astellas Agreement” means the Co-Development and Commercialization Agreement by and between CPC (as successor-in-interest to Maxygen) and Astellas Pharma Inc., a Japanese corporation, (“Astellas”), dated September 18, 2008, as the same may be amended from time to time.

1.6 “Astellas Agreement Technology” means the Astellas Agreement Know-How and Astellas Agreement Patents.

1.6.1 “Astellas Agreement Know-How” means Know-How and Materials, if any, that (i) is Controlled by Maxygen or an Affiliate as of the Effective Date or at any time during the Term prior to the Survival Date (subject to Section 2.5 with respect to New Third Party Agreements, if any, entered into by Maxygen after the Date of the Master Joint Venture Agreement), (ii) is not assigned to CPC under the Asset Contribution Agreement, and (iii) is (a) resulting from or generated under the 4 Program as conducted by or for Maxygen prior to the Effective Date (including all CTLA-4 Variants), or used (or has been used) in, or useful for, the 4 Program or both the 4 Program and the Other Programs in each case as conducted (or anticipated to be conducted) by or for Maxygen as of or prior to the Effective Date, (b) within the scope of Know-How licensed to Astellas under the Astellas Agreement (determined as if Maxygen remained a party thereto), or (c) was practiced by Maxygen in performance of its obligations or exercise of its rights under the Astellas Agreement prior to the Effective Date or are necessary or useful for CPC in performance of its

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obligations or exercise of its rights under the Astellas Agreement after the Effective Date. Notwithstanding the foregoing, the Astellas Agreement Know-How does not include any Know-How or Materials within the Excluded Technology or any Enabling Know-How or Enabling Materials.

1.6.2 “Astellas Agreement Patents” means (I) any Patents, if any, that (i) are Controlled by Maxygen or an Affiliate as of the Effective Date or during the Term of this Agreement (subject to Section 2.5 with respect to New Third Party Agreements, if any, entered into by Maxygen after the Date of the Master Joint Venture Agreement), (ii) are not assigned to CPC under the Asset Contribution Agreement, and (iii) are (a) resulting from or generated under the 4 Program as conducted by or for Maxygen prior to the Effective Date (including all CTLA-4 Variants), or used (or has been used) in, or useful for, the 4 Program or both the 4 Program and the Other Programs in each case as conducted (or anticipated to be conducted) by or for Maxygen as of or prior to the Effective Date, (b) within the scope of Patents licensed to Astellas under the Astellas Agreement (determined as if Maxygen remained a party thereto), or (c) were practiced by Maxygen in performance of its obligations or exercise of its rights under the Astellas Agreement or are necessary or useful for CPC to in performance of its obligations or exercise of its rights under the Astellas Agreement, and (II) any Patents whether filed or issued as of or after the Effective Date that claim priority to any Patent included within (I). Notwithstanding the foregoing, the Astellas Agreement Patents do not include any Patents within the Excluded Technology or any Enabling Patents.

1.7 “Bayer Agreement” means that certain License Agreement by and between Maxygen, Inc. and Bayer HealthCare LLC, dated July 1, 2008, as may be amended by the parties thereto from time to time.

1.8 “Business Day” means any day other than a Saturday, Sunday or any other day on which commercial banks in Tokyo, Japan or San Francisco, California (as applicable) are authorized or required by Law to remain closed.

1.9 “Buy-Out Option” shall have the meaning provided in the Investors’ Rights Agreement by and between Maxygen, CPC and Astellas of even date herewith.

1.10 “CMVP Technology” means the CMVP Patents, CMVP Materials and CMVP Know-How.

1.10.1 “CMVP Know-How” means Know-How Controlled by Maxygen or an Affiliate as of the Effective Date related to the cytomegalovirus (“CMV”) promoter, or variants thereof, that is reasonably necessary and/or useful for making or using CMVP Materials as research reagents.

1.10.2 “CMVP Materials” means the CMV promoter variants and related Materials listed on Exhibit 1.10.2.

1.10.3 “CMVP Patents” means (I) the Patents listed on Exhibit 1.10.3, (II) any other Patents, if any, that (i) are Controlled by Maxygen or an Affiliate as of the Effective Date and (ii) claim the composition, or are directed to the manufacture or use of, CMV promoter variants

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made or used by Maxygen prior to the Effective Date, and (III) any Patents whether filed or issued as of or after the Effective Date that claim priority to any Patent included within (I) or (II). CMVP Patents shall also include future patent applications and patents issuing thereon to the extent they have utility in the manufacture, use or sale of CMV immediate early promoter variants and claim priority to any Patents within the scope of the foregoing sentence (provided, however, that with respect to continuation-in-part applications, only those claims thereof which claim priority to a date on or before the Effective Date shall be included in the license hereunder). Notwithstanding the foregoing, the CMVP Patents do not include any Patents licensed to Maxygen by the University of Iowa Research Foundation or any other Patents within the Excluded Technology.

1.11 “Compound” means (i) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a human or humanized protein, or any variant, homolog, derivative, mutant or fragment thereof, in each case other than any Excluded Protein Variant or Vaccine, (each, a “Protein Molecule”) and (ii) any Protein Molecule that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation). For the avoidance of doubt, Compounds include any CTLA-4 Variants and Other Protein Variants (as such terms are defined in the Asset Contribution Agreement).

1.12 “Contributor Technology” means the Contributor Patents and Contributor Know-How.

1.12.1 “Contributor Know-How” means Know-How within the Contributor Intellectual Property (as defined in the Asset Contribution Agreement) assigned to CPC under the Asset Contribution Agreement; provided, however, that Contributor Know-How shall exclude all such Know-How resulting from or generated under the 4 Program (as defined in the Asset Contribution Agreement) as conducted by or for Maxygen as of or prior to the Effective Date.

1.12.2 “Contributor Patents” means Patents within the Other Program Intellectual Property (but excluding those Patents listed on Schedule 2.1(b)(2) of the Asset Contribution Agreement) and Other Contributor Intellectual Property (as those terms are defined in the Asset Contribution Agreement) assigned to CPC under the Asset Contribution Agreement; provided, however, that Contributor Patents shall exclude all such Patents resulting from or generated under the 4 Program (as defined in the Asset Contribution Agreement) as conducted by or for Maxygen as of or prior to the Effective Date, and shall for the avoidance of doubt exclude all Patents listed on Schedule 2.1(a) of the Asset Contribution Agreement.

1.13 “Control” means, with respect to particular Know-How and any and all non-Patent intellectual property rights therein, or a particular Patent, possession by the Party granting the applicable right, license or sublicense to the other Party as provided herein, of the power and authority, whether arising by ownership, license, or other authorization, to disclose and, if applicable, to deliver the particular Know-How to the other Party, and to grant and to authorize under such Know-How or Patent the right, license or sublicense, as applicable, to such other Party in this Agreement (i) without giving rise to a violation of the terms of any written agreement with any Third Party, and (ii) subject to the provisions of Section 2.5, below, with respect to rights, licenses or sublicenses conveyed to Maxygen under Third Party Agreements or New Third Party Agreements that are subject to payment obligations to such Third Parties. “Controlled” and “Controlling” have their correlative meanings.

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1.14 “CTLA-4 Variants” shall have the meaning provided in the Asset Contribution Agreement.

1.15 “Dollars” or “$” refers to United States dollars.

1.16 “Enabling Technology” means the Enabling Patents, Enabling Materials, and Enabling Know-How.

1.16.1 “Enabling Know-How” means Know-How Controlled by Maxygen or an Affiliate as of the Effective Date directed to (a) methods of performing Shuffling (whether using tangible materials or in silico), or (b) generally applicable screening techniques, methodologies or processes for identifying genetic variants of interest, in each case that are reasonably necessary or useful for using or practicing the Enabling Patents and/or the Enabling Materials in and for the research, development, manufacture or commercialization of Compounds and Products in the Field.

1.16.2 “Enabling Materials” means the Materials listed on Exhibit 1.16.2.

1.16.3 “Enabling Patents” means (I) the Patents listed on Exhibit 1.16.3, (II) all other Patents that (i) are Controlled by Maxygen or an Affiliate as of the Effective Date and (ii) claim (a) methods of performing Shuffling (whether using tangible materials or in silico), or (b) generally applicable screening techniques, methodologies or processes for identifying genetic variants of interest, or (c) Software useful for the performance of Shuffling or analysis of resulting Shuffled proteins, and (III) any Patents whether filed or issued as of or after the Effective Date that claim priority to any Patent included within (I) or (II). Enabling Patents shall include future patent applications and patents issuing thereon to the extent they have utility in the performance of Shuffling or generally applicable screening techniques, methodologies or process for identifying genetic variants of interest and claim priority to any Patents within the scope of the foregoing sentence (provided, however, that with respect to continuation-in-part applications, only those claims thereof which claim priority to a date on or before the Effective Date shall be included in the license hereunder). Notwithstanding the foregoing, Enabling Patents shall exclude all Patents within the Excluded Technology.

1.17 “Excluded Protein Variant or Vaccine” means (i) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is an (A) Exclusively Out-Licensed Protein, (B) granulocyte colony stimulating factor (G-CSF), (C) a protein from an infectious agent or a polynucleotide encoding such protein that in each case is intended to be used as a Vaccine (including infectious agents or other constructs incorporating a Vaccine and/or genetic material encoding a Vaccine (including live-attenuated or whole killed virus), but solely when such agent, construct or material is included with or otherwise incorporates a protein from an infectious agent (or variant, homolog, derivative, mutant or fragment of such protein as described in (D), below) or a polynucleotide encoding such protein (or such variant, homolog, derivative, mutant or fragment) and is intended to be used as a Vaccine), or (D) any variant, homolog, derivative, mutant, or fragment of the amino acid chains described in the foregoing subsections (A), (B) or (C), which in

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the case of (C) is intended to be used as a Vaccine (each, an “Excluded Protein Molecule”) and (ii) any Excluded Protein Molecule that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation). In no event shall Excluded Protein Variant or Vaccines include any CTLA-4 Variants or (x) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a protein or polypeptide listed on Schedule 2.1(b)(1) of the Asset Contribution Agreement, or (y) any variant, homolog, derivative, mutant, or fragment of subsection of (x), provided that in the case of (y) such variant, homolog, derivative, mutant, or fragment has not been altered or modified in such a way as to cause such variant, homolog, derivative, mutant, or fragment to fall within (A), (B), or (C) of the definition of Excluded Protein Variant or Vaccine set forth in the first sentence of this Section 1.17 or to fall within (D) above such that a reasonable, independent expert knowledgeable and experienced in working with protein pharmaceuticals would primarily consider such variant, homolog, derivative, mutant, or fragment to be a variant of a protein or polypeptide within (A), (B) or (C) above or a material portion thereof (rather than as a variant of some other protein or material portion thereof).

1.18 “Excluded Technology” means the Patents, Materials and Know-How of Third Parties (sub)licensed to Maxygen under the agreements specified in Exhibit 1.18 (or, where indicated on Exhibit 1.18 as only partially excluded agreements, the rights of Maxygen with respect to specific Patents indicated as “excluded” that are licensed to Maxygen under such agreement and, for the avoidance of doubt, Patents not so indicated as excluded or otherwise not licensed under any agreements specified in Exhibit 1.18 are not within Excluded Technology).

1.19 “Exclusively Out-Licensed Protein” has the meaning set forth in Exhibit 1.19 attached hereto.

1.20 “Field” means: (i) with respect to Compounds and Products that are Resulting Products derived in whole or part from Shuffling conducted prior to January 1, 2017, the Treatment of human diseases or conditions, and (ii) with respect to all other Compounds and Products, the Treatment or diagnosis of human diseases or conditions. For the avoidance of doubt, the Field includes discovery, research, development and/or commercialization of (x) such Compounds and Products that are Resulting Products for such Treatment, and (y) such other Compounds and Products for such Treatment and diagnosis, and the Field excludes discovery, research, development and/or commercialization of any Excluded Protein Variant or Vaccine.

1.21 “G-CSF Variant” means (i) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is a granulocyte colony stimulating factor (G-CSF) or any variant, homolog, derivative, mutant, or fragment thereof (each, a “G-CSF Molecule”) and (ii) any G-CSF Molecule that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation).

1.22 “Governmental Authority” means any: (a) nation, principality, state, commonwealth, province, territory, county, municipality, district or other jurisdiction of any nature; (b) federal, state, local, municipal, foreign or other government; (c) governmental or quasi governmental authority of any nature (including any governmental division, subdivision, department, agency, bureau, branch, office, commission, council, board, instrumentality, unit, or body and any court or other legal tribunal); or (d) any governmental multinational organization or body.

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1.23 “In-Licensed Project-Specific Technology” means the Patents, Materials and Know-How licensed to Maxygen pursuant to the Letter Agreement between InterMune, Inc. and Maxygen Holdings Ltd., dated July 27, 2007.

1.24 “Know-How” means any and all data and information including (i) ideas, discoveries, inventions (whether or not patentable and whether or not reduced to practice), technology, improvements or trade secrets; (ii) research and development data, such as medicinal chemistry data, nonclinical data, preclinical data, pharmacology data, chemistry data (including analytical, product characterization, manufacturing, and stability data), toxicology data, clinical data (including investigator reports (both preliminary and final), statistical analyses, expert opinions and reports, safety and other electronic databases), analytical and quality control data and stability data, in each case together with supporting data; (iii) databases, data compilations and collections, specifications, formulations, formulae; (iv) practices, knowledge, techniques, methods, formulas, processes, manufacturing information, including technical data and customer and supplier lists; (v) information regarding research materials, reagents and compositions of matter; (vi) works of authorship including, without limitation, computer programs, source code and executable code, whether embodied in software, firmware or otherwise, documentation, designs, files, net lists, records, data and mask works; and (vii) copies of the foregoing in any form and embodied in any media. Know-How excludes any Patent rights with respect thereto (but does include information in unpublished patent applications).

1.25 “Law” means, individually and collectively, any and all laws, ordinances, rules, directives and regulations of any kind whatsoever of any governmental or regulatory authority within the applicable jurisdiction.

1.26 “Licensed Technology” means the Enabling Technology, the Software, the In-Licensed Project-Specific Technology, the RR Technology, the Other Program Technology, the Astellas Agreement Technology, and the CMVP Technology; provided, however, that “Licensed Technology” excludes the Excluded Technology.

1.27 “Material” means any chemical or biological substances including any: (i) organic or inorganic chemical element or compound; (ii) nucleic acid; (iii) vector of any type (e.g., cosmid, plasmid, spore, phage, virus, or virus-like particle), and subunits of the foregoing; (iv) host organism, including prokaryotic cells, eukaryotic cells or animals; (v) eukaryotic cell line, prokaryotic cell line or expression system; (vi) protein, including any peptide or amino acid sequence, enzyme, antibody or protein conferring targeting properties and any fragment of any of the foregoing; (vii) genetic material, including any genetic nucleic acid construct, marker gene and genetic control element (e.g., promoter, termination signal), gene, genome or variant of any of the foregoing; or (viii) assay or reagent, including compounds, clinical candidates, compound libraries, animal models, and other physical, biological or chemical material, in each case which exist and are Controlled by Maxygen or an Affiliate prior to the Effective Date.

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1.28 “Maxygen Change of Control” means (a) the acquisition of Maxygen by a Third Party by means of any transaction or series of related transactions to which the Maxygen is party (including, without limitation, any stock acquisition, reorganization, merger or consolidation but excluding any bona fide sale of stock for capital raising purposes) other than a transaction or series of transactions in which the holders of the voting securities of the Maxygen outstanding immediately prior to such transaction continue to retain (either by such voting securities remaining outstanding or by such voting securities being converted into voting securities of the surviving entity), as a result of shares in the Maxygen held by such holders prior to such transaction, at least fifty percent (50%) of the total voting power represented by the voting securities of Maxygen or such surviving entity outstanding immediately after such transaction or series of transactions; or (b) a sale, lease, exclusive license or other conveyance of all or substantially all of the assets of Maxygen.

1.29 “MaxyBody” shall have the meaning set forth on Exhibit 1.29.

1.30 “CPC Change of Control” means (a) the acquisition of CPC by an entity other than Maxygen or an Affiliate of Maxygen by means of any transaction or series of related transactions to which the CPC is party (including, without limitation, any stock acquisition, reorganization, merger or consolidation but excluding any bona fide sale of stock for capital raising purposes) other than a transaction or series of transactions in which the holders of the voting securities of the CPC outstanding immediately prior to such transaction continue to retain (either by such voting securities remaining outstanding or by such voting securities being converted into voting securities of the surviving entity), as a result of shares in the CPC held by such holders prior to such transaction, at least fifty percent (50%) of the total voting power represented by the voting securities of CPC or such surviving entity outstanding immediately after such transaction or series of transactions; (b) a sale, lease, exclusive license or other conveyance of all or substantially all of the assets of CPC; or (c) the Option Closing.

1.31 “Option Closing” shall have the meaning assigned to in Section 5.1 of the Investors’ Rights Agreement by and between Maxygen, CPC and Astellas of even date herewith.

1.32 “Other Program Technology” means the Other Program Patents and Other Program Know-How.

1.32.1 “Other Program Know-How” means Know-How and Materials, if any, Controlled by Maxygen or an Affiliate as of the Effective Date and not assigned to CPC under the Asset Contribution Agreement, that are (a) resulting from or generated under the Other Programs as conducted by or for Maxygen prior to the Effective Date (including any Other Protein Variants), or used (or have been used) in, or useful for, a particular Other Program as conducted (or anticipated to be conducted) by or for Maxygen as of or prior to the Effective Date, or (b) used in, or useful for, more than one particular Program that is not otherwise included in (a). Notwithstanding the foregoing, Other Program Know-How does not include any Know-How or Materials within the Excluded Technology, the Enabling Know-How, or the Enabling Materials.

1.32.2 “Other Program Patents” means (I) Patents, if any, Controlled by Maxygen or an Affiliate as of the Effective Date and not assigned to CPC under the Asset Contribution Agreement that are (a) resulting from or generated under the Other Programs as

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conducted by or for Maxygen prior to the Effective Date (including any Other Protein Variants), or used (or have been used) in, or useful for, a particular Other Program as conducted (or anticipated to be conducted) by or for Maxygen as of or prior to the Effective Date, or (b) used in, or useful for, more than one particular Program that is not otherwise included in (a); and (II) any Patents whether filed or issued as of or after the Effective Date that claim priority to any Patent included within (I). Notwithstanding the foregoing, Other Program Patents do not include any Patents within the Excluded Technology or the Enabling Patents.

1.33 “Other Programs” shall have the meaning provided in the Asset Contribution Agreement.

1.34 “Other Protein Variants” shall have the meaning provided in the Asset Contribution Agreement.

1.35 “Patent” means any of the following, existing at any time in any country or other jurisdiction anywhere in the world: (i) any issued patent (including inventor’s certificates, utility model, petty patent and design patent), extensions, confirmations, reissues, re-examination, renewal, supplementary protection certificates or any like governmental grant for protection of inventions; and (ii) any pending application for any of the foregoing, including any request for continued examination (RCE), continuations, continuations-in-part, divisionals, provisionals, converted provisionals, continued prosecution applications, or substitute applications.

1.36 “Programs” shall have the meaning provided in the Asset Contribution Agreement.

1.37 “Product” means any pharmaceutical product that contains a Compound as an ingredient. For avoidance of doubt, Product shall include any formulation, delivery device, dispensing device or packaging required for effective use of the Product.

1.38 “Resulting Product” means any of the following (i) any Resulting Genetic Material, (ii) any vector of any type (e.g., cosmid, plasmid, spore, phage, virus, or virus-like particle), and subunits of the foregoing, which contain any Resulting Genetic Material, (iii) any organism, including any prokaryotic or eukaryotic cell or animal containing any Resulting Genetic Materials; (iv) any Resulting Protein; (iv) any eukaryotic cell, prokaryotic cell or expression systems expressing, secreting or otherwise producing a Resulting Protein; or (v) any product containing in whole or part, or made with or using in whole or part, any of the foregoing, in each case, in purified or unpurified form, and alone or in combination with other substances, and including any modifications, derivatives, progeny (altered or unaltered) or fragments of any of the foregoing.

1.38.1 “Resulting Genetic Material” means any genetic material (including DNA or RNA) that is generated, created or otherwise results directly from Shuffling.

1.38.2 “Resulting Protein” means any protein, polypeptide, antibody or other molecule encoded in whole or part by any Resulting Genetic Material.

1.39 “RR Technology” means the RR Patents, RR Materials, and RR Know-How, in each case Controlled by Maxygen or an Affiliate as of the Effective Date; provided, however, that RR Technology shall not include any Excluded Technology.

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1.39.1 “RR Know-How” means Know-How Controlled by Maxygen or an Affiliate as of the Effective Date related to methods of cell selection related to selective suppression of stop codons during protein translation that is reasonably necessary or useful for using the RR Patents and RR Materials in or for research, development, manufacture, or use of Compounds and Products in the Field. Notwithstanding the foregoing, the RR Know-How does not include any Know-How within the Excluded Technology.

1.39.2 “RR Materials” means the Materials listed on Exhibit 1.39.2.

1.39.3 “RR Patents” means (I) the Patents listed on Exhibit 1.39.3, (II) any other Patents, if any, that (i) are Controlled by Maxygen or an Affiliate as of the Effective Date and (ii) claim methods of cell selection related to selective suppression of stop codons during protein translation, and (III) any Patents whether filed or issued as of or after the Effective Date that claim priority to any Patent included within (I) or (II). RR Patents shall also include future patent applications and patents issuing thereon to the extent they have utility in the methods of cell selection related to selective suppression of stop codons during protein translation and claim priority to any Patents within the scope of the foregoing sentence (provided, however, that with respect to continuation-in-part applications, only those claims thereof which claim priority to a date on or before the Effective Date shall be included in the license hereunder). Notwithstanding the foregoing, the RR Patents do not include any Patents within the Excluded Technology.

1.40 “Software” means, individually and collectively, the software programs for use with the Enabling Technology that are listed on Exhibit 1.40.

1.41 “Shuffle” means techniques, methodologies, processes, materials or instrumentation for performing recombination-based modification of genetic material for the creation of potentially useful variant nucleic acids or proteins. “Shuffled” and “Shuffling” have their correlative meanings.

1.42 “Subsidiary” shall mean an Affiliate of CPC that is “controlled” by CPC (as the word “control” is defined in the definition of Affiliate, above) directly or indirectly through one or more intermediaries.

1.43 “Survival Date” shall have the meaning assigned to it in the Master Joint Venture Agreement by and between Maxygen, CPC and Astellas of even date herewith.

1.44 “Territory” means all countries and territories of the world.

1.45 “Third Party” means any entity other than Maxygen or CPC, or their respective Affiliates. For the avoidance of doubt, sublicensees which are not an Affiliate of Maxygen or CPC shall be included in the definition of Third Party.

1.46 “Third Party Agreement” means the agreements listed on Exhibit 1.46, and any other written license or agreement entered into by Maxygen or any of its Affiliates and a Third Party prior to the date of the Master Joint Venture Agreement, but not terminated or expired prior to such date with no license or other rights granted to Maxygen surviving after such termination or expiration, and pursuant to which Maxygen or any of its Affiliates obtained a license under Patents or Know-How within the Licensed Technology. Notwithstanding the foregoing, Third Party Agreements do not include any agreements with Third Parties that are within the Excluded Technology.

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1.47 “Treatment” means, with respect to a particular indication, the prophylaxis, cure, reduction, mitigation, prevention, slowing or halting the progress of, or otherwise management of such indication. “Treat” and “Treating” means providing Treatment.

1.48 “Vaccine” means a formulation intended to be administered in a formulation containing one or more Antigen(s) (and/or a nucleic acid sequence encoding an Antigen) in the form of (i) an infectious agent (e.g., bacteria, viruses, parasite, protozoa) whether live, attenuated or dead, (ii) protein(s), (iii) nucleic acid(s), (iv) cells, spores and vectors (i.e., viruses and/or virus-like particles, liposomes, beads and/or other substrates for Antigen presentation), (v) fragments of any of the foregoing, and/or (vi) a combination of any of the preceding, which formulation is administered for the purpose of inducing an Immune Response in the human and/or animal recipient specifically directed to at least one such Antigen for the prevention or treatment of a disease state, symptom and/or condition in humans and/or animals caused by an infectious agent. For the purposes of this definition of Vaccine:

1.48.1 “Antigen” means a molecule (i.e., protein, polypeptide, peptide, carbohydrate, glycoprotein, glycolipid and/or any combination of the foregoing that is, or is derived in whole or part from, a molecule associated with an infectious agent) that produces an Immune Response to such molecule in a human and/or animal recipient; and

1.48.2 “Immune Response” means an immune state directed to the applicable infectious agents (or a molecule associated with such infectious agent) resulting from the modulation of activity (i.e., an increase, decrease and/or qualitatively different activity) of one or more lymphoid cells (e.g., B cells, NK cells, T cells and/or professional antigen-presenting cells, such as monocytes, macrophages, Langerhans cells, dendritic cells) following the administration of a stimulus.

1.49 Additional Definitions. Each of the following definitions shall have the meaning defined in the corresponding sections of this Agreement indicated below:

Definitions	Section	Definitions	Section
Agreement	Preamble	Fault of Maxygen	7.1.1(b)
AME	2.7	ICC Rules	9.2
AME License Agreement	2.7	Indemnified Party	7.2
Asset Contribution Agreement	Background	Indemnifying Party	7.2
Avidia	2.4.2	Losses	7.1.1(a)
Claims	7.1.1(a)	Master Joint Venture Agreement	10.7
Coagulation Factor Variant	6.3.10	Maxygen	Preamble
Confidential Information	5.1	Maxygen Indemnitees	7.1.1(a)
CPC	Preamble	New Third Party Agreement	2.5.2
CPC Improvements	6.3.5	Parties	Preamble

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Definitions	Section	Definitions	Section
CPC Indemnitees	7.1.1(b)	Party	Preamble
CPC Other Improvements	4.5.2	Representing Party	6.1
Dispute	9.1	SEC	5.2
Effective Date	Preamble	Term	8.1
Fault of CPC	7.1.1(a)

1.50 Interpretation. The captions and headings to this Agreement are for convenience only, and are to be of no force or effect in construing or interpreting any of the provisions of this Agreement. Unless specified to the contrary, references to Articles, Sections or Exhibits mean the particular Articles, Sections or Exhibits to this Agreement and references to this Agreement include all Exhibits hereto. Each accounting term used herein that is not specifically defined herein shall have the meaning given to it under applicable Accounting Standards, but only to the extent consistent with its usage and the other definitions in this Agreement. Unless context otherwise clearly requires, whenever used in this Agreement: (i) the words “include” or “including” shall be construed as incorporating, also, “but not limited to” or “without limitation;” (ii) the word “day” or “year” means a calendar day or calendar year unless otherwise specified; (iii) the word “notice” means notice in writing (whether or not specifically stated) and shall include notices, consents, approvals and other communications contemplated under this Agreement; (iv) the words “hereof,” “herein,” “hereby” and derivative or similar words refer to this Agreement (including all Exhibits); (v) the word “or” shall be construed as the inclusive meaning identified with the phrase “and/or;” (vi) provisions that require that a Party, the Parties or any committee or team hereunder “agree,” “consent” or “approve” or the like shall require that such agreement, consent or approval be specific and in writing, whether by written agreement, letter, approved minutes or otherwise; (vii) words of any gender include the other gender; and (viii) references to any specific Law or article, section or other division thereof shall be deemed to include the then-current amendments thereto or any replacement Law thereof. This Agreement was prepared in the English language, which language shall govern the interpretation of, and any dispute regarding, the terms of this Agreement.

ARTICLE 2

LICENSES TO CPC

2.1 License Grants.

2.1.1 Enabling Technology.

(a) License Grant. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Sections 4.3 and 8.3), license under the Enabling Technology to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Compounds and Products in the Territory (including, for the avoidance of doubt, making and using Enabling Technology to discover, research and develop Compounds and Products in the Territory and otherwise conduct the Programs), solely for use in the Field, which license shall be (i) non-exclusive with respect to Adjuvants and Products

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containing such Adjuvants, and (ii) exclusive (but subject to the licenses granted by Maxygen prior to the Effective Date which are listed on Exhibit 2.1.1, and a non-exclusive license, if any, granted by Maxygen to the Third Party involved in the litigation disclosed in Exhibit 6.2.6 in settlement of such litigation, but in the case of such settlement solely with respect to the Patents that are the subject of such litigation, foreign counterparts of such Patents, and Patents that claim priority to such Patents or foreign counterparts) with respect to all other Compounds and related Products.

(b) No License Outside the Field. It is understood and agreed that the licenses set forth above do not convey any license to practice the Enabling Technology in or for any purpose outside the Field, and without limitation specifically excludes any use of the Enabling Technology to generate, identify or create Resulting Products intended for use outside the Field (e.g., for diagnostic purposes). For clarity, the license with respect to Adjuvants set forth above includes the right to develop and commercialize Adjuvants in Products containing Vaccines, but does not include any right or license to practice Shuffling for the purpose of researching, developing, generating or creating Resulting Products which are Vaccines.

2.1.2 In-Licensed Project-Specific Technology. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3) exclusive license under the In-Licensed Project-Specific Technology to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Compounds and Products in the Territory, solely for use in the Field (including, for the avoidance of doubt, the right to make and use the In-Licensed Project-Specific Technology itself in connection therewith).

2.1.3 RR Technology. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3) non-exclusive license under the RR Technology to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Compounds and Products in the Territory, solely for use in the Field (including, for the avoidance of doubt, the right to make and use the RR Technology itself in connection therewith).

2.1.4 CMVP Technology. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3) non-exclusive license under the CMVP Technology to use the CMVP Materials (and materials derived therefrom) as research reagents in the Territory. CPC acknowledges that (i) the license from Maxygen to use the CMVP Materials does not include any sublicense or right under the Patents licensed by University of Iowa Research Foundation to Maxygen or its Affiliates, and (ii) the CMVP Materials are subject to restriction on their use for any purpose other than as research reagents.

2.1.5 Software. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3) non-exclusive license with respect to the Software in the Territory, to use, modify, reproduce, copy,

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maintain, fix, improve enhance, display, or create derivative works of the Software in the Territory in connection with the exercise of the license to Enabling Technology provided in Section 2.1.1 above or otherwise to research, develop, make and have made, use, import, sell, offer for sale and otherwise commercially exploit any Compound or Product in the Field; provided, however, that no license is granted with respect to uses of the Software (or modifications, improvements, enhancements or derivative works thereof) in connection with the practice of Shuffling (whether with tangible materials or in silico) for uses outside of the Field or in connection with Shuffling of any Excluded Protein Variant or Vaccine. CPC acknowledges that Maxygen has informed CPC that the Software is designed and intended to function with, and may not function properly or to its full extent without, the Third Party software listed on Exhibit 2.1.5. A list of such Third Party software used by Maxygen in connection with its use of the Software as of the Effective Date is set forth in Exhibit 2.1.5. CPC or its Affiliates shall be responsible, in its discretion and at its expense, for obtaining any Third Party software (and appropriate licenses therefor) that CPC or its Affiliates may want or require for use in connection with the Software, other than such Third Party software and licenses as may be included within the Contributed Assets under the Asset Contribution Agreement.

2.1.6 Other Program Technology. Subject to the terms and conditions herein (including Sections 2.3, 2.4, and 2.5), effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3) license under the Other Program Technology to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Compounds and Products in the Territory, solely for use in the Field (including, for the avoidance of doubt, the right to make and use the Other Program Technology itself in connection therewith), which license shall be (i) non-exclusive with respect to Adjuvants and Products containing such Adjuvants, and (ii) exclusive with respect to all other Compounds and related Products.

2.1.7 Astellas Agreement Technology License Grant. Subject to the terms and conditions herein, effective as of the Effective Date, Maxygen hereby grants to CPC, and CPC hereby accepts, an irrevocable, perpetual, exclusive license under the Astellas Agreement Technology (i) to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Compounds and Products in the Territory, solely for use in the Field (including, for the avoidance of doubt, the right to make and use the Astellas Agreement Technology itself in connection therewith), (ii) to perform its obligations and exercise its rights under the Astellas Agreement, and (iii) to grant sublicenses of the Astellas Agreement Technology to Astellas to the extent of the license grants to Astellas under the Astellas Agreement.

2.1.8 Royalty-Free Licenses. Except with respect to CPC’s obligation to pay Maxygen amounts due to Third Parties as set forth in Section 2.5, the licenses granted to CPC under this Section 2.1 shall be fully paid up and royalty-free.

2.1.9 Development and Improvement of Licensed Technology. Maxygen and CPC agree that that the licenses set forth above include the right to develop and improve each of the Enabling Technology, Astellas Agreement Technology, In-Licensed Project-Specific Technology, Other Program Technology, RR Technology, CMVP Technology and Software in or for the purpose of exercise of the applicable license above.

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2.2 Sublicensing; Subcontractors. Subject to Section 2.3, CPC shall have the right to grant and authorize sublicenses within the scope the licenses set forth in Section 2.1; provided, however, that CPC may not grant or authorize sublicenses under the licenses set forth in Sections 2.1.1 or 2.1.5 prior to a CPC Change of Control without the prior written consent of Maxygen, which shall not be unreasonably withheld, until such time as a CPC Change of Control occurs at which point such consent shall no longer be required. For clarity, it is understood and agreed that the foregoing limitations shall not be construed to prohibit CPC or its Affiliates from granting licenses (including sublicenses) to Third Parties with respect to any Compounds or Products for uses in the Field (and no consent of Maxygen shall be required therefore), so long as such license to a Third Party does not include a license to practice the Enabling Technology per se or any license with respect to the Software (or in each case, modifications, improvements, enhancements or derivative works thereof). Notwithstanding the foregoing limitation on sublicensing with respect to the licenses under Sections 2.1.1 or 2.1.5 above, CPC may use consultants, temporary employees or other Third Party service providers to perform activities on behalf of CPC in the practice of the Enabling Technology or Software (or in each case, modifications, improvements, enhancements or derivative works thereof), under a written contract containing reasonable confidentiality provisions and containing a covenant from such Third Party not to practice the Enabling Technology, Software or improvements thereto other than on behalf of CPC until expiration, on a patent-by-patent basis, of applicable Patents within the Enabling Patents; provided, however, that all Shuffling, if any, is conducted at CPC’s facilities. CPC shall obligate any and all such Third Party service providers to comply with applicable confidentiality terms set forth herein (including the restrictions both on disclosure and on use).

2.3 Limitation on Licenses.

2.3.1 Limited Maxygen Rights. It is understood and agreed that with respect to any aspect of the Enabling Technology, In-Licensed Project-Specific Technology, Other Program Technology, RR Technology, CMVP Technology or Software for which Maxygen has less than fully exclusive, worldwide rights (i.e., co-exclusive, non-exclusive, limited territorial or otherwise restricted rights) as of the Effective Date (as provided under any Third Party Agreement listed on Exhibit 1.46 or under any New Third Party Agreement pursuant to which CPC obtains rights under Section 2.5.2), the licenses provided in Section 2.1 shall be limited to the scope of those rights that Maxygen Controls and has the right to license or sublicense to CPC to the extent provided under such Third Party Agreement or New Third Party Agreement.

2.3.2 Maxygen Exercise of Retained Rights. CPC acknowledges and agrees that Maxygen retains the right, without violating any term of this Agreement, to practice the Enabling Technology, In-Licensed Project-Specific Technology, Other Program Technology, RR Technology or CMVP Technology, and to use, modify, reproduce, copy, maintain, fix, improve or enhance, display, or create derivative works of the Software (and to grant to Maxygen’s Affiliates or to any Third Parties any or all such rights), in all such cases for any use other than to conduct activities or practice Know-How, Patents or Materials within the scope of the exclusive license to CPC set forth herein. Maxygen and its Affiliates shall have the right to sell or otherwise dispose of the Enabling Technology, In-Licensed Project-Specific Technology, Astellas Agreement Technology, Other Program Technology, RR Technology, CMVP Technology or Software, subject to the licenses and associated rights to enforce granted to CPC hereunder with regard thereto, provided that (i) prior to

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any sale or disposition of any Patents, or proprietary rights in Know-How or Materials, owned by Maxygen or its Affiliates and licensed to CPC hereunder, Maxygen shall obtain written agreement from the person or entity acquiring such Patents and/or such proprietary rights in Know-How or Materials that all such Patents and/or proprietary rights in Know-How or Materials are subject to the licenses (and any applicable associated enforcement rights) granted to CPC hereunder, and (ii) prior to assignment of any Third Party Agreement or New Third Party Agreement conveying to Maxygen rights which are sublicensed to CPC hereunder, Maxygen shall obtain written agreement from the person or entity to which such Third Party Agreement or New Third Party Agreement is assigned that such assignment is subject to the sublicense to CPC (and, if such Third Party Agreement or New Third Party Agreement conveys Maxygen enforcement rights within the Field with respect to Patents within the Enabling Technology, any applicable associated enforcement rights granted to CPC hereunder). Within thirty (30) days of any such sale or disposition, Maxygen shall provide written notice to CPC identifying the Patents, Materials and/or Know-How sold or disposed of and the person or entity acquiring such Patents, Materials and/or Know-How. Without limiting the foregoing, Maxygen specifically retains the right under the Licensed Technology to research, develop, practice, make, have made, use, sell, offer for sale, import, and otherwise commercialize Adjuvants in the Territory, and to license Third Parties to do so. At all times during and after this Agreement, nothing herein shall restrict, or be construed to restrict, Maxygen’s or its Affiliates’ right to practice and grant licenses to practice the Enabling Technology or use related Know-How, outside the Field or with respect to research, development, manufacture and commercial exploitation of molecules that are not Compounds or Products.

2.3.3 U.S. Government Rights. CPC acknowledges that certain of the inventions claimed in the Patents within the Enabling Technology listed on Exhibit 2.3.3 have been made with funds provided by the U.S. Government, and that with respect thereto the U.S. government retains a non-exclusive license as set forth in 35 U.S.C. §202. In addition, CPC acknowledges that 35 U.S.C. §200 et seq. sets forth additional obligations with regard to inventions made with U.S. government funds (with respect to Patents listed on Exhibit 2.3.3 and products based thereon), including a preference for manufacture in the United States pursuant to 35 U.S.C. §204.

2.3.4 Reporting. From the Effective Date until the earlier of a Maxygen Change of Control or CPC Change of Control, up to once per year, upon Maxygen’s request, CPC shall provided to Maxygen a summary report regarding activities of CPC, its Subsidiaries and sublicensees under the licenses granted hereunder in sufficient detail for Maxygen to determine compliance by CPC, its Subsidiaries and sublicensees with Section 6.3.4, including a general description of the type of proteins Shuffled by CPC and Compounds and Products derived in whole or in part from the practice of the Enabling Technology. After a Maxygen Change of Control or CPC Change of Control has occurred, up to once per year, upon Maxygen’s request, CPC shall provide to Maxygen a certificate of compliance indicating that CPC, its Subsidiaries and sublicensees are in compliance with Section 6.3.4. The Parties acknowledge that reports provided to CPC’s representatives of the JSC under the Other Products Collaboration Agreement between CPC and Astellas Pharma Inc. of even date herewith, may, to the extent they include such information, satisfy the reporting requirement set forth in this Section 2.3.4 until a Maxygen Change of Control or CPC Change of Control.

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2.4 Third Party Rights. CPC hereby acknowledges that Maxygen has informed CPC prior to the Effective Date that:

2.4.1 In connection with the initial establishment of Maxygen, Maxygen entered into the Affymax/Maxygen Technology Transfer Agreement, effective February 1, 1997, entered by and among Affymax Technologies N.V., Glaxo Group Limited and Maxygen, as amended on March 1, 1998, subject to the letter agreements dated January 14, 2000 and December 17, 2001, pursuant to which Maxygen has granted perpetual, worldwide, non-exclusive licenses to certain entities associated with Glaxo Wellcome Companies (as defined in that agreement) to use certain Enabling Technology for internal research purposes only, and CPC hereby agrees that the rights and licenses granted CPC in Section 2.1 with respect to Enabling Technology are subject to such licenses.

2.4.2 Pursuant to that certain Cross-License Agreement between Maxygen and Avidia Research Institute (“Avidia”) dated as of July 16, 2003, subject to the letter agreement dated March 29, 2005, Maxygen has granted a non-exclusive license to practice certain claims of Patents within the Enabling Technology with respect to MaxyBodies. In addition, Maxygen assigned to Avidia certain Patents related to MaxyBodies that do not claim methods of Shuffling, and CPC acknowledges that the Licensed Technology does not include such Patents.

2.4.3 Third Parties granting or conveying rights to Maxygen or its Affiliates under the Third Party Agreements listed on Exhibit 1.46 have retained rights with respect to some of the Enabling Technology pursuant to those agreements all in accordance with the terms and conditions thereof, and in some cases such Third Parties’ rights are subject to retained rights of their Third Party licensors.

2.4.4 Prior to the Effective Date, Maxygen or its Affiliates have granted to the Third Parties listed on Exhibit 2.4.4 under the agreements specified on such exhibit, licenses or rights with respect to Enabling Technology for uses outside the Field or to research, develop, manufacture ands commercialize molecules that are not Compounds, and that after the Effective Date, Maxygen or its Affiliates may grant licenses under the Enabling Technology and related Know-How to other Third Parties (including to Affiliates or former Affiliates of Maxygen) for uses outside the Field to research, develop, manufacture and commercialize molecules that are not Compounds or Products.

2.4.5 Prior to the Effective Date, Maxygen and its Affiliates have granted to Bayer HealthCare LLC and its Affiliates under the Bayer Agreement licenses and rights under the Enabling Technology (and Software) to practice the Enabling Technology and use the Software to, among other things, Shuffle any and all proteins, except any of the Maxygen Exclusive Proteins (as defined in the Bayer Agreement) during the applicable Exclusivity Period (as defined in the Bayer Agreement) for such Maxygen Exclusive Protein, with the right to develop, make, have made, use, import, sell, offer for sale, market and otherwise commercially exploit the Resulting Products in the Field as defined in this Agreement (as well as certain uses outside the Field), which license (i) is exclusive with respect to Shuffling of certain Bayer Exclusive Proteins (as defined in the Bayer Agreement) and corresponding Resulting Products for the applicable Exclusivity Period (as defined in the Bayer Agreement) and (ii) is otherwise non-exclusive.

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2.5 Third Party Agreements; New Third Party Agreements.

2.5.1 Existing Third Party Agreements. CPC acknowledges that, with respect to Patents, Know-How and Materials licensed to Maxygen pursuant to a Third Party Agreement listed on Exhibit 1.46, the sublicense by Maxygen to CPC is subject and subordinate to all applicable restrictions, and all obligations expressly applicable to sublicensees, set forth in such Third Party Agreement, and both CPC and Maxygen acknowledge that any breach of such restrictions and obligations under such Third Party Agreements by CPC or its Affiliates, or a breach of such Third Party Agreements by Maxygen, may result in damage to Maxygen, CPC or other licensees of either Party with respect to the subject Licensed Technology, which may include loss of license rights to such Licensed Technology or monetary damages. CPC acknowledges that, with respect to Patents, Know-How and Materials licensed to Maxygen as of the Effective Date pursuant to the Third Party Agreements listed on Exhibit 1.46, the sublicense by Maxygen to CPC (or the exercise by CPC or its Affiliates of such sublicense) may result in payment obligations to the Third Party under such Third Party Agreements, which payment obligations that may arise are those annual payments, milestone payments, royalties on product sales, or other similar payments provided under the sections of such Third Party Agreements indicated on Exhibit 2.5.1, and those provided in Third Party Agreements listed on Exhibit 1.46 with respect to indemnity obligations or the sharing of costs and/or recoveries in connection with enforcement or defense of Patents to the extent expressly provided to be extended to, or shared with, sublicensees such as CPC. CPC agrees to pay any such amounts due by Maxygen to such Third Parties with respect to payment obligations indicated in Exhibit 2.5.1, or with respect to indemnity obligations or the sharing of costs and/or recoveries in connection with enforcement or defense of Patents under Third Party Agreements listed on Exhibit 1.46, unless and until CPC elects to forego its rights under such Third Party Agreement as provided below.

2.5.2 Future Agreements with Third Parties. For any written license or agreement entered into by Maxygen or any of its Affiliates and a Third Party after the date of the Master Joint Venture Agreement pursuant to which Maxygen or any of its Affiliates first obtains a license with respect to Patents or Know-How within the Licensed Technology subject to the sublicense to CPC hereunder (a “New Third Party Agreement”) and for which the sublicense from Maxygen to CPC (or exercise thereof by CPC or its Affiliates) may result in payment obligations to the Third Party, or which would impose obligations on CPC as a sublicensee, Maxygen shall provide written notice to CPC of the applicable New Third Party Agreement, including a copy thereof containing all provisions applicable to sublicensees and all provisions describing such payment obligations. If CPC notifies Maxygen in writing within thirty (30) days of such notification from Maxygen that CPC agrees to undertake such payment obligations attributable to the grant of the sublicense to CPC (or exercise thereof by CPC or its Affiliates) and to comply with all provisions of such New Third Party Agreement applicable to sublicensees, the applicable Licensed Technology under such New Third Party Agreement shall be sublicensed under the license grants hereunder. If CPC fails to so notify Maxygen of its agreement to undertake such payment obligations within such thirty (30) day period, the applicable Licensed Technology under such New Third Party Agreement shall not be sublicensed to CPC hereunder (and CPC shall have no obligation to make any payments with respect to such New Third Party Agreement).

2.5.3 CPC Election to Forego Sublicense(s). At any time, CPC shall have the right, in its sole discretion, to terminate its sublicense rights hereunder under a given Third Party

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Agreement or a given New Third Party Agreement under which CPC obtains a sublicense pursuant to Section 2.5.2, on an agreement-by-agreement basis, by providing written notice indicating that it no longer desires a sublicense to Licensed Technology under such Third Party Agreement or New Third Party Agreement. Following the provision of such written notice: (i) CPC shall thereafter have no sublicense under this Agreement with respect to the Licensed Technology under the applicable Third Party Agreement or New Third Party Agreement; (ii) CPC shall have no further obligation to make any payments hereunder with respect to such Third Party Agreement or New Third Party Agreement (but, for the avoidance of doubt, shall remain responsible for payments thereunder attributable to activities by or under authority of CPC prior to CPC’s written notice under this Section 2.5.3); and (iii) CPC shall, as between the Parties hereto, thereafter no longer be subject to the applicable terms and conditions thereof (provided, however, that CPC shall remain responsible to comply with applicable confidentiality obligations and indemnity obligations under such Third Party Agreement or New Third Party Agreement, and applicable restrictions, if any, on the use of tangible materials provided subject to the sublicense under such Third Party Agreement or New Third Party Agreement, in each case to the extent reasonably considered as required to survive termination of CPC’s rights thereunder).

2.6 No Future IP; No Implied Rights. CPC acknowledges and agrees that (i) no rights or licenses are conveyed to CPC hereunder with respect to Patents, Know-How, Materials or other materials, know-how or intellectual property rights that are invented, created, first acquired, licensed to or otherwise obtained by Maxygen or any of its Affiliates after the Effective Date, and (ii) no rights or licenses are conveyed to CPC hereunder with respect to any Patents, Know-How, Materials or other materials, know-how or intellectual property rights owned or Controlled by any Third Party that becomes an Affiliate of Maxygen after the Effective Date that are not already licensed hereunder prior to such entity becoming an Affiliate. Accordingly, except for the rights and licenses expressly granted under this Agreement and without limiting any right granted under any written agreement entered into by the Parties, no right, title, or interest of any nature whatsoever is granted whether by implication, estoppel, reliance, or otherwise, by Maxygen to CPC hereunder. All rights with respect to Materials, Know-How, Patents or other intellectual property rights that are not expressly granted herein are reserved to the owner thereof. Notwithstanding the foregoing, (a) the Patents licensed hereunder to CPC shall include Patents filed or issued after the Effective Date that claim priority to any Patent within the Licensed Technology as of the Effective Date (in the case of Patents owned by Third Parties, to the extent Controlled by Maxygen), and (b) the Astellas Agreement Technology and the licenses granted to CPC hereunder with respect thereto shall include such future Patents and Know-How as are expressly provided for under the definition of Astellas Agreement Technology.

2.7 AME License upon CPC Change of Control. Under the License Agreement between Applied Molecular Evolution, Inc. (“AME”) and Maxygen, effective January 13, 2004 (the “AME License Agreement”), AME granted a nonexclusive sublicense under certain Patents within the Enabling Technology in Section 2.1.1 of the AME License Agreement to Maxygen and its Affiliates (as defined in the AME License Agreement), which Affiliates include CPC as of the Effective Date. This nonexclusive sublicense granted in Section 2.1.1 of the AME License Agreement may be assigned in connection with the sale or transfer of all or substantially all of the business or assets of such Affiliate (as defined in the AME License Agreement) pursuant to Section 10.2.2 of the AME License Agreement. In the event of a CPC Change of Control including, without limitation, the

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Option Closing, Maxygen and CPC agree that the nonexclusive sublicense granted to Maxygen and its Affiliates (as defined in the AME License Agreement) in Section 2.1.1 of the AME License Agreement will hereby be automatically assigned to CPC (or the successor, purchaser or transferee of CPC with respect to such CPC Change of Control, as applicable) upon the consummation of such CPC Change of Control, pursuant to Section 10.2.2 of the AME License Agreement whereby the sublicense to an Affiliate (as defined in the AME License Agreement) of Maxygen may be assigned. In the event of such CPC Change of Control upon reasonable request of CPC, Maxygen shall, and shall cause its Affiliates and its and their employees and agents, to provide CPC with such execution, acknowledgement and recordation of specific assignments, oaths, declarations and other documents and other instruments of sale, transfer, conveyance, and assignment as CPC may reasonably request to effectuate such assignment of the sublicense to CPC under the AME License Agreement in accordance with Section 10.2.2 of the AME License Agreement.

2.8 Bayer Agreement Coordination. The Parties acknowledge and agrees that the Bayer Agreement requires the number of Maxygen Exclusive Proteins (as defined in the Bayer Agreement) to be reduced on the first, second, and third anniversaries of the Closing Date (as defined in the Bayer Agreement) of the Bayer Agreement. The initial list of Maxygen Exclusive Proteins contains thirty (30) proteins. Maxygen and CPC agree that CTLA-4 shall never be removed from the list of Maxygen Exclusive Proteins. Maxygen and CPC agree that CPC shall have the right to elect which proteins shall be removed the Maxygen Exclusive Proteins list upon each anniversary where there is a reduction in the number of proteins on such the Maxygen Exclusive Proteins list.

2.8.1 At least five (5) days prior to the second, and third anniversaries of the Closing Date of the Bayer Agreement, CPC shall submit to Maxygen a list of the proteins to remove from the Maxygen Exclusive Proteins list. Before the first anniversary, CPC shall have the right to submit to Maxygen a list of seven (7) proteins to remove from the Maxygen Exclusive Proteins list. Before the second anniversary, CPC shall have the right to submit to Maxygen a list of five (5) proteins to remove from the Maxygen Exclusive Proteins list. Before the third anniversary, CPC shall have the right to submit to Maxygen a list of three (3) proteins to remove from the Maxygen Exclusive Proteins list. Upon timely receipt of such list by Maxygen, Maxygen shall timely provide written notice to Bayer of the proteins to remove in accordance with Section 2.5.5(b) of the Bayer Agreement. If Bayer provides Maxygen notice requesting that Maxygen identify the proteins to be removed in accordance with Section 2.5.5(b) of the Bayer Agreement, Maxygen shall forward such notice to CPC within five (5) days of receipt of such notice and shall thereafter provide Bayer any list of proteins to be removed provided to Maxygen by CPC. Maxygen shall in no event submit a list of proteins to be removed in accordance with Section 2.5.5(b) of the Bayer Agreement which includes a protein that CPC has not requested be removed without the prior written approval of CPC, which approval is in CPC’s sole discretion.

2.8.2 If CPC desires to substitute any of the Maxygen Exclusive Proteins with a protein that CPC reasonably believes has application in the area of immunosuppression (including autoimmunity and/or transplant rejection), Maxygen shall inform CPC of the number of substitutions that are allowed and use commercially reasonable efforts in order to accomplish the requested substitution in accordance with the procedures of Section 2.5.6 of the Bayer Agreement. Maxygen and CPC acknowledge that such substitutions may only be made by written notice within thirty (30) days of the first, second and/or third anniversary of the Closing Date of the Bayer Agreement and

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that Bayer has a right of consent to such substitutions that will not be unreasonably withheld. Maxygen and CPC further acknowledge that Maxygen may not substitute one of its Maxygen Exclusive Proteins with a protein that is at the time a Bayer Exclusive Protein (as defined in the Bayer Agreement) and that Maxygen shall only identify proposed substitution proteins that are in Maxygen’s Area of Interest (as defined in the Bayer Agreement) in the area of immunosuppression, including autoimmunity and/or transplant rejection. If CPC desires to substitute any of the Maxygen Exclusive Proteins, CPC shall provide Maxygen with a list of the proteins to be substituted to Maxygen no later than twenty-five (25) days following the applicable anniversary of the Closing Date of the Bayer Agreement. After timely receipt by Maxygen of a list of proposed proteins to be added and the corresponding proteins to be replaced, Maxygen shall provide a Substitution Notice (as defined in the Bayer Agreement) to Bayer as soon as reasonably possible, but in no event later than within thirty (30) days of the relevant anniversary of the Closing Date of the Bayer Agreement. If Bayer provides Maxygen with an Objection Notice of the proposed substitution proteins, Maxygen shall promptly provide CPC with a copy of such notice and shall cooperate and use reasonable efforts to include CPC in all discussions regarding such objection (and if Bayer is unwilling to include CPC in such discussions, shall consult with and take all reasonable direction from CPC with respect to such discussions). If so requested by CPC, Maxygen shall take any legal actions available to Maxygen reasonably requested by CPC to contest Bayer’s opposition to the substitution, at CPC’s expense. If Bayer consents to the substitution or otherwise does not object to the proposed substitution protein within thirty (30) days after receiving the Substitution Notice, the proposed substitution protein shall become a Maxygen Exclusive Protein and Maxygen shall provide notice thereof to CPC. Maxygen shall in no event request a substitution of a protein in accordance with Section 2.5.6 of the Bayer Agreement without the prior written approval of CPC, which approval is in CPC sole discretion.

2.8.3 If Bayer provides a Substitution Notice to Maxygen proposing substitution proteins, Maxygen shall promptly provide a copy of such notice to CPC. CPC shall, within twenty-five (25) days following Maxygen’s receipt of such Substitution Notice from Bayer, either provide to Maxygen its written consent to such substitution or a draft Objection Notice if CPC reasonably objects to such substitution. After timely receipt by Maxygen of CPC’s written consent to such substitution or a draft Objection Notice, Maxygen shall provide a copy of such written consent or Objection Notice to Bayer within thirty (30) days of Maxygen’s receipt of Bayer’s Substitution Notice. Maxygen shall cooperate and use reasonable efforts to include CPC in all discussions related to an Objection Notice provided to Bayer (and if Bayer is unwilling to include CPC in such discussions, shall consult with and take all reasonable direction from CPC with respect to such discussions). If so requested by CPC, Maxygen shall take any legal actions available to Maxygen reasonably requested by CPC to oppose Bayer’s proposed substitution, at CPC’s expense.

2.8.4 The Parties acknowledge that the exclusivity provisions of the Bayer Agreement expire at the expiration of the “Exclusivity Period” as defined in the Bayer Agreement, and agree that the obligations of Maxygen under this Section 2.8 shall expire on July 1, 2013. In the event that Maxygen assigns the Bayer Agreement to any Third Party prior to July 1, 2013, Maxygen shall obtain written agreement from such Third Party to comply with the foregoing obligations set forth in this Section 2.8.

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ARTICLE 3

LICENSES TO MAXYGEN

3.1 License Grants.

3.1.1 Contributor Technology.

(a) License Grant. Subject to the terms and conditions herein (including Sections 3.3 and 3.4), effective as of the Effective Date, CPC hereby grants to Maxygen, and Maxygen hereby accepts, an irrevocable (except, and solely to the extent, as set forth in Section 8.3), license under the Contributor Technology (i) to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize compounds and products that are neither Compounds nor Products, in the Territory, solely for use in the outside of the Field (including, for the avoidance of doubt, the right to make and use the Contributor Technology itself in connection therewith), which license shall be exclusive, and (ii) to research, develop, make, have made, use, sell, offer for sale, import, and otherwise commercialize Adjuvants and products containing such Adjuvants (but such license shall not extend to other Compounds, if any, that are not Adjuvants but are contained in such products), which license shall be non-exclusive, in each case subject to all licenses under such Contributor Technology granted by Maxygen prior to the Effective Date.

(b) No License Inside the Field. It is understood and agreed that the licenses set forth above do not convey any license to practice the Contributor Technology in or for any purpose within the Field or otherwise with respect to Compounds or Products (and CPC retains all such rights), except with respect to the non-exclusive license with respect to Adjuvants. For clarity, the license with respect to Adjuvants set forth above includes the right to develop and commercialize Adjuvants in the Field in or with products containing Vaccines, but does not include any right or license to practice Shuffling for the purpose of researching, developing, generating or creating Adjuvants for use in the Field independent of Vaccines.

3.1.2 Royalty-Free Licenses. Except with respect to Maxygen’s obligation to pay CPC amounts due to Third Parties as set forth in Section 3.4, the licenses granted to Maxygen under this Section 3.1 shall be royalty-free and fully paid up.

3.2 Sublicensing. Subject to Section 3.3, Maxygen shall have the right to grant and authorize sublicenses within the scope the licenses set forth in Section 3.1. Maxygen shall obligate all such sublicensees to which Maxygen conveys Confidential Information within the Contributor Technology to comply with applicable confidentiality terms set forth herein (including the restrictions both on disclosure and on use) with respect to such Contributor Technology.

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3.3 Limitation on Licenses. It is understood and agreed that with respect to any aspect of the Contributor Technology for which CPC has less than fully exclusive, worldwide rights (i.e., co-exclusive, non-exclusive, limited territorial or otherwise restricted rights) as of the Effective Date, the licenses provided in Section 3.1 shall be limited to the scope of those rights that CPC Controls and has the right to license or sublicense to Maxygen.

3.4 Third Party Agreements. The Parties acknowledge that, with respect to Patents, Know-How and Materials in the Contributor Technology licensed to Maxygen pursuant to a Third Party agreement assigned to CPC under the Asset Contribution Agreement, the sublicense by CPC to Maxygen is subject and subordinate to all restrictions and obligations applicable to sublicensees set forth in such Third Party agreement, and that any breach of such restrictions and obligations under such Third Party agreements by a Party or its Affiliates may result in damage to the other Party or other licensees of CPC with respect to the subject Contributor Technology, which may include loss of license rights to such Contributor Technology or monetary damages. Maxygen acknowledges that, with respect to Patents, Know-How and Materials licensed to CPC pursuant to any such Third Party agreement, the sublicense by CPC to Maxygen (or the exercise by Maxygen or its Affiliates of such sublicense) may result in payment obligations to the Third Party under such Third Party agreements. Maxygen agrees to pay any such amounts due by CPC to such Third Parties for the grant of the sublicense to Maxygen hereunder (or the exercise thereof by Maxygen or its Affiliates), unless and until Maxygen elects to forego its rights under such Third Party agreement as provided below. At any time, Maxygen shall have the right, in its sole discretion, to terminate its sublicense rights from CPC hereunder under a given Third Party agreement, on an agreement-by-agreement basis, by providing written notice indicating that it no longer desires a sublicense to Contributor Technology under such Third Party agreement. Following the provision of such written notice: (i) Maxygen shall thereafter have no sublicense under this Agreement with respect to the Contributor Technology under the applicable Third Party agreement; (ii) Maxygen shall have no further obligation to make any payments hereunder with respect to such Third Party agreement (but, for the avoidance of doubt, shall remain responsible for payments thereunder attributable to activities by or under authority of Maxygen prior to Maxygen’s written notice under this Section 3.4); and (iii) Maxygen shall, as between the Parties hereto, thereafter no longer be subject to the applicable terms and conditions thereof (provided, however, that Maxygen shall remain responsible to comply with applicable confidentiality obligations and indemnity obligations under such Third Party agreement, and applicable restrictions, if any, on the use of tangible materials provided subject to the sublicense under such Third Party agreement, in each case to the extent reasonably considered as required to survive termination of Maxygen’s rights thereunder).

3.5 No Future IP; No Implied Rights. Maxygen acknowledges and agrees that (i) no rights or licenses are conveyed to Maxygen hereunder with respect to Patents, Know-How, Materials or other materials, know-how or intellectual property rights that are invented, created, first acquired, licensed to or otherwise obtained by CPC or any of its Affiliates after the Effective Date, and (ii) no rights or licenses are conveyed to Maxygen hereunder with respect to any Patents, Know-How, Materials or other materials, know-how or intellectual property rights owned or Controlled by any Third Party that becomes an Affiliate of CPC after the Effective Date that are not already licensed hereunder prior to such entity becoming an Affiliate. Accordingly, except for the rights expressly granted under this Agreement and without limiting any right granted under any written agreement entered into by the Parties, no right, title, or interest of any nature whatsoever is granted whether by

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implication, estoppel, reliance, or otherwise, by CPC to Maxygen hereunder. All rights with respect to Materials, Know-How, Patents or other intellectual property rights that are not expressly granted herein are reserved to the owner thereof. Notwithstanding the foregoing, the Patents licensed hereunder to Maxygen shall include Patents filed or issued after the Effective Date that claim priority to any Patent within the Contributor Technology (in the case of Patents owned by Third Parties, to the extent Controlled by CPC).

ARTICLE 4

INTELLECTUAL PROPERTY

4.1 Ownership. The ownership of any intellectual property right in subject matter developed or otherwise made by a Party in connection with this Agreement shall be determined in accordance with the applicable Law of the jurisdiction in which such subject matter was developed or otherwise made.

4.2 Prosecution. As between the Parties, Maxygen shall have sole responsibility for deciding, in its sole discretion, on behalf of Maxygen or its Affiliates or licensees, whether to file U.S., PCT or foreign patent applications, copyrights, the contents and subject matter of any such filing, whether (and in what manner) to continue prosecution of any patent applications or to maintain any Patent or copyright, or whether (and in what manner) to defend any oppositions and interferences, reissues or reexaminations regarding the Licensed Technology at its sole expense. As between the Parties, CPC shall have sole responsibility for deciding, in its sole discretion, on behalf of CPC or its Affiliates or licensees, whether to file U.S., PCT or foreign patent applications, copyrights, the contents and subject matter of any such filing, whether (and in what manner) to continue prosecution of any patent applications or to maintain any Patent or copyright, or whether (and in what manner) to defend any oppositions and interferences, reissues or reexaminations regarding the Contributor Technology at its sole expense.

4.3 Patent Challenges.

4.3.1 If CPC or any of its Affiliates challenges the validity or enforceability of any Patent within the Enabling Patents listed on Exhibit 1.16.3 in any court or before any Governmental Authority with authority to determine the validity or enforceability of such Patent and CPC or its Affiliate fails to dismiss or otherwise withdraw from such court or Governmental Authority proceeding within forty-five (45) days of Maxygen’s providing notice setting forth the identity of the Patent so challenged and the proceeding in which such Patent is challenged with a request for CPC or its Affiliate to dismiss or otherwise withdraw from such proceeding, Maxygen shall have the right to terminate the license granted to CPC hereunder with respect to such challenged Patent upon written notice to CPC.

4.3.2 CPC agrees that it shall provide reasonable assistance requested by Maxygen at Maxygen’s expense in connection with any litigation between Maxygen or any of its Affiliates with any Third Parties, where such Third Party challenges the validity or enforceability of any Patent Right within the Licensed Technology, including the pending litigation with Alligator Biosciences AB. CPC agrees not to provide knowingly any voluntary assistance to any such Third Party with respect to such challenge, and shall not provide any Confidential Information of Maxygen to such

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Third Party without Maxygen’s express prior written consent unless, and solely to the extent, required by applicable Law or pursuant to agreements entered into prior to such litigation. CPC and its Affiliates shall notify Maxygen if they receive a subpoena, request or demand for any such Maxygen Confidential information from or on behalf of any such Third Party, and shall reasonably cooperate, as requested by Maxygen, to resist or limit the scope of such disclosure.

4.4 Improvements to Enabling Technology.

4.4.1 Maxygen Improvements. Maxygen and its Affiliates and licensees shall be entitled to make improvements, modifications, enhancements and changes to the Enabling Technology and shall have no obligation to assign or license any such improvements, modifications, enhancements or changes to CPC.

4.4.2 CPC Improvements. CPC and its Subsidiaries and permitted sublicensees shall be entitled to make improvements, modifications, enhancements and changes to the Enabling Technology and In-Licensed Program-Specific Technology and shall have no obligation to assign or license any such improvements, modifications, enhancements or changes to Maxygen or any of its Affiliates.

4.5 RR Technology, CMVP Technology and Software.

4.5.1 Maxygen Other Improvements. Maxygen and its Affiliates and licensees shall be entitled to make improvements, modifications, enhancements and changes to the RR Technology, CMVP Technology and Software and shall have no obligation to assign or license any such improvements, modifications, enhancements or changes to CPC. Notwithstanding the foregoing, to the extent Maxygen obtains, during the period from the Effective Date until July 1, 2012, a license, with the right to sublicense, under any Patents owned or controlled by Bayer HealthCare LLC (or its successor-in-interest under Bayer Agreement or its affiliate) claiming any Bayer Other Improvements (as defined in the Bayer Agreement) pursuant to Section 5.3 of the Bayer Agreement, Maxygen agrees to grant to CPC a non-exclusive sublicense thereunder, with the right to further sublicense, under such Patents of the same scope as the licenses granted under Sections 2.1.3, 2.1.4, and 2.1.5, as applicable, in each case, only to the extent Maxygen is able to grant such sublicense under the applicable license from Bayer; provided that such license from Bayer HealthCare LLC to Maxygen shall be deemed a Third Party Agreement for all purposes of this Agreement, and accordingly, to the extent provided under Section 2.5, CPC agrees to pay to Maxygen all amounts due from Maxygen to Bayer for the grant of such sublicense(s) to CPC or the practice of such sublicense(s) by CPC or its Affiliates of their licensees and to otherwise comply with the applicable terms of such license. Notwithstanding the foregoing, this Section 4.5.1 shall not be deemed to be an obligation upon Maxygen, or a right of CPC, to obtain a license or sublicense under Section 5.3 of the Bayer Agreement, or the right to sublicense to CPC, under any Patent owned or controlled by Bayer HealthCare LLC (or its successor-in-interest under Bayer Agreement or its affiliate) claiming improvements, modifications, enhancements or changes to the RR Technology, CMVP Technology or Software.

4.5.2 CPC Other Improvements. CPC and its Subsidiaries shall be entitled to make improvements, modifications, enhancements and changes to the RR Technology, CMVP

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Technology and to make modifications, improvements, enhancements or derivative works from the Software (individually or collectively, the “CPC Other Improvements”). With respect to CPC Other Improvements made by CPC or its Subsidiary prior to a CPC Change of Control, CPC agrees to grant, and to cause its Subsidiaries to grant, to Bayer HealthCare LLC (or its successor-in-interest under Bayer Agreement or its affiliate) a non-exclusive license, with the right to sublicense, under Patents owned or controlled by CPC or any of its Subsidiaries claiming any CPC Other Improvement, for any use by Bayer in the Territory, as provided in Section 5.2.2 of the Bayer Agreement, and to comply with the provisions and procedures described in Section 5.3 of the Bayer Agreement for purposes of determining financial terms of such license.

4.6 Third Party Infringement.

4.6.1 Notice. If a Party or any of its Affiliates becomes aware of any actual or potential infringement of any Patents in the Licensed Technology or Contributor Technology, or if either Party becomes aware of any declaratory judgment action or similar proceeding with respect to any Patents within the Licensed Technology or Contributor Technology, then such Party shall promptly notify the other Party in writing. Upon request of either Party, the Parties shall discuss such actual or potential infringement in the Licensed Technology or Contributor Technology, as well as whether and how to enforce such Patents within the Licensed Technology or Contributor Technology with respect to such infringement, and allocation of costs and expenses related thereto.

4.6.2 Interest of Various Parties. CPC hereby acknowledges that there are and will be multiple licensees of the Licensed Technology and that Maxygen has the responsibility to determine how to best enforce and defend the Patents within the Licensed Technology for the benefit of all licensees, including Third Parties other than CPC, and CPC further acknowledges that such responsibility may affect Maxygen’s determination whether to enforce or defend particular Patents within the Licensed Technology in any particular instance. CPC acknowledges that (i) certain Patents within the Licensed Technology are and will be owned by Third Parties and, that in some cases, such Third Parties may retain or have retained the first right, or the sole right, to enforce or defend such Patents, and (ii) prior to the Effective Date, Maxygen has granted to Third Parties under the Third Party Agreements listed on Exhibit 1.46 rights to conduct or participate in the enforcement or defense of Patents within the Licensed Technology owned by Maxygen.

4.6.3 Infringement in Field. For any infringement, declaratory action or similar proceeding with respect to the Patents within the Enabling Patents, Astellas Agreement Patents or Other Program Patents, which infringement occurs in the Field (or declaratory judgment action is brought by a Third Party alleging threat of enforcement of such Patent with respect to activities in the Field), CPC shall have the right to request in writing that Maxygen enforce such Patents within the Enabling Patents against such infringement, describing CPC’s information and knowledge with respect to such actual or suspected infringement and basis for its belief how such infringement, action or proceeding involved the use of Enabling Patents, Astellas Agreement Patents or Other Program Patents within the Field. Upon receiving such a written request, Maxygen shall have one hundred and eighty (180) days after receipt of such request to examine and evaluate the facts and circumstances regarding such infringement, action or proceeding, as well as the interests of Maxygen and its Affiliates and Third Parties with respect to the Enabling Patents, Astellas Agreement Patents or Other Program Patents and to determine in Maxygen’s discretion whether to

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institute suit or take other action to abate such infringement, action or proceeding, at Maxygen’s expense. If Maxygen or its Affiliate does not institute suit or take other action to abate such infringement, action or proceeding within such 180-day period or if Maxygen institutes but does not maintain or continue through resolution, then CPC may, at CPC’s expense, institute suit to enforce the Enabling Patents, Astellas Agreement Patents or Other Program Patents against such infringement, action or proceeding in the Field with respect to a Compound or Product that is a Resulting Product, subject to the consent of the owner of the applicable Patents if such Patents are not owned by Maxygen or its Affiliates, and subject to any rights granted to a Third Party prior to the Effective Date pursuant to a Third Party Agreement listed on Exhibit 1.46; provided that until the expiration of such 180-day period, CPC shall not take any action to enforce, or threaten to enforce, such Patent against such infringement, action or proceeding. Any recoveries from such enforcement attributable to infringement, action or proceeding of the Enabling Patents, Astellas Agreement Patents or Other Program Patents within the Field with respect to a Compound or Product shall first be used to reimburse the expenses of the Parties (including amounts paid by the Party controlling such action for the expenses of the other Party) with the remainder shared (as between the Parties) as follows: (i) sixty percent (60%) to the Party controlling such action; and (ii) forty percent (40%) to the other Party. Any recoveries from such enforcement attributable to outside the Field or compounds or products other than Compounds or Products shall belong exclusively to Maxygen.

4.6.4 Cooperation. In connection with any such claim, suit or proceeding subject to Section 4.6.3, the Parties shall reasonably cooperate with each other and shall keep each other reasonably informed of all material developments in connection with any such claim, suit or proceeding. At the request and expense of the Party initiating any such claim, suit or proceeding, the other Party agrees to join in any such claim, suit or proceeding in the event that the other Party is necessary or indispensable to such proceedings, or such joinder of such Party is otherwise required, by applicable Law.

4.7 Defense of Third Party Action. If a Third Party institutes any action to have any patent within the Patents within the Licensed Technology other than Enabling Technology held invalid, non-infringed or unenforceable, the Parties agree to discuss, in good faith with each other (and with the owner of the applicable Patents if these are not owned by Maxygen or its Affiliates, and any Third Parties to whom Maxygen or its Affiliates has granted rights regarding enforcement or defense of such Patents prior to the Effective Date), which Party (or Third Party) should control the defense of such action. All of the out-of-pocket costs and legal fees relative to such defense shall be shared if and to the extent agreed by the Parties (and applicable Third Parties). If there is any recovery of out-of-pocket costs and legal fees, the recovery shall, unless otherwise agreed, be used to reimburse the Parties (and applicable Third Parties) according to the proportion of out-of-pocket costs and legal fees each Party (or applicable Third Party) paid, and the remaining recovery will be split according to the proportion of out-of-pocket costs and legal fees each Party (or applicable Third Party) paid. If the Parties cannot agree on which Party will prosecute a suit or the sharing of the costs, then as between the Parties, (i) Maxygen shall have the right to determine whether and, if so, how to prosecute or defend such suit and will be entitled to name CPC as a party in such suit if CPC is a necessary or indispensable party, and (ii) Maxygen shall be responsible for all of the out-of-pocket costs and legal fees of Maxygen and CPC relative to such suit Maxygen prosecutes or defends, and any recoveries from such suit shall belong exclusively to Maxygen.

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4.8 Settlement. No Party shall enter into an agreement to settle any action with respect to Licensed Technology covered by this Article 4 which agreement would conflict with, or materially diminish, the rights granted to or retained by the other Party with respect to the Licensed Technology, nor enter into any such agreement which makes any admission of wrongdoing by the other Party or any admission of the invalidity, unenforceability or absence of infringement of any Patents licensed hereunder, in each case without first obtaining the written consent of the other Party, which consent shall not be unreasonably withheld, conditioned or delayed.

ARTICLE 5

CONFIDENTIALITY

5.1 Confidentiality; Exceptions. Except to the extent expressly authorized by this Agreement or otherwise agreed in writing, the Parties agree that each Party shall keep confidential and shall not publish or otherwise disclose or use for any purpose other than for the purpose of exercising its retained rights or rights under licenses granted hereunder, or performing obligations hereunder, or as otherwise provided for in this Agreement or in any Transaction Agreements (as that term is defined in the Master Joint Venture Agreement) or the Astellas Agreement, any confidential and proprietary information and materials of the other Party (collectively, “Confidential Information”). Licensed Technology shall be deemed the Confidential Information of Maxygen for purposes of this Agreement. Contributor Technology shall be deemed the Confidential Information of CPC for purposes of this Agreement. Notwithstanding the foregoing, Confidential Information shall not include any information to the extent that it can be established by written documentation by the receiving Party that such information:

5.1.1 was already known to the receiving Party, at the time of disclosure, other than under an obligation of confidentiality (except to the extent such obligation has expired or an exception is applicable under the relevant agreement pursuant to which such obligation established), and except or to the extent such information was already known to the receiving Party solely because or as a result of any employee of the receiving Party previously obtaining such information while an employee of the disclosing Party;

5.1.2 was generally available to the public or otherwise part of the public domain at the time of its disclosure to the receiving Party;

5.1.3 became generally available to the public or otherwise part of the public domain after its disclosure and other than through any act or omission of the receiving Party in breach of this Agreement;

5.1.4 was independently discovered or developed by the receiving Party without reference to or use of Confidential Information of the disclosing Party as demonstrated by documented evidence; or

5.1.5 was disclosed to the receiving Party, other than under an obligation of confidentiality (except to the extent such obligation has expired or an exception is applicable under the relevant agreement pursuant to which such obligation established), by a Third Party who had no obligation to the disclosing Party not to disclose such information to others.

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The obligations set forth in this Section 5.1 shall remain in effect during the Term of this Agreement and for five (5) years thereafter.

5.2 Authorized Disclosure. Except as expressly provided otherwise in this Agreement, each Party may use and disclose Confidential Information of the other Party as follows: (i) under appropriate confidentiality provisions substantially equivalent to those in this Agreement (but for a confidentiality period that is reasonable and customary under the applicable circumstances) in connection with the performance of its obligations or as reasonably necessary or useful in the exercise of its rights under this Agreement, including the right to grant licenses or sublicenses or extension of the licenses and sublicenses to Affiliates and subcontractors as permitted hereunder; (ii) to the extent such disclosure is reasonably necessary in prosecuting or maintaining any Patent or other intellectual property right in accordance with this Agreement, prosecuting or defending litigation related to this Agreement, complying with applicable governmental regulations with respect to performance under this Agreement (including to comply with the applicable rules of any public stock exchange upon which the stock of such Party or its Affiliate is listed), provided that the Party seeking to disclose Confidential Information of the other Party uses commercially reasonable efforts, consistent with typical practice in the biopharmaceutical industry, to secure confidential treatment thereof, as applicable; (iii) to the extent such disclosure is otherwise required by Law, provided, however, that if a Party is required by Law or court order to make any such disclosure of the other Party’s Confidential Information it will, except where impracticable for necessary disclosures (for example, in the event of medical emergency), give reasonable advance notice to the other Party of such disclosure requirement and, in each of the foregoing, (but not to the extent inappropriate in the case of Prosecution and Maintenance of Patents), will use its reasonable efforts to seek confidential treatment of such Confidential Information required to be disclosed and limit disclosure of the Confidential Information to only that part necessary to comply with the request; any disclosure of Confidential Information as permitted in the foregoing sentence shall not alter the confidential nature of such Confidential Information for all other purposes; (iv) in communication with advisors (including financial advisors, lawyers and accountants) or actual or bona fide potential investors or acquirers, or actual or bona fide potential licensees or sublicensees related to Products, or approved or permitted contractors, service providers, vendors and the like used (or to be used) in connection with activities hereunder, each on a need to know basis, and in each case under standard confidentiality obligations (subject to the allowances for term of confidentiality provided in subsection (i) above, except with respect to disclosures to actual or bona fide potential investors and acquirers receiving any technical data or information related to Compounds or Products or the Licensed Technology that is Confidential Information of the other Party shall be subject to obligations of confidentiality for a period of at least five (5) years after such disclosure, or (v) to the extent mutually agreed to by the Parties. In addition to the foregoing, with respect to complying with the disclosure requirements of the U.S. Securities and Exchange Commission (“SEC”) or similar regulatory bodies or the rules of an applicable public stock exchange, in connection with any required disclosure of material information related to this Agreement, the Parties shall consult with one another concerning the information to be disclosed and secure confidential treatment thereof where practicable. If time does not permit such discussion, or if after such discussion between counsel, the Party desiring to make the disclosure still believes such Party is required by applicable Law or applicable stock exchange rule to make such disclosure, it may do so, upon written notice to the other Party. For clarity, nothing in this Section 5.2 shall prevent any Party from making disclosures required by applicable Law.

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5.3 Confidential Terms. Each of the Parties agrees not to disclose to any Third Party the terms and conditions of this Agreement without the prior approval of the other Party, except: (i) to advisors (including financial advisors, attorneys and accountants), approved or permitted contractors, actual or bona fide potential investors or acquirers, or actual or bona fide potential licensees or sublicensees or others on a need to know basis, in each case under circumstances that reasonably ensure the confidentiality thereof; or (ii) under circumstances that reasonably ensure the confidentiality of the information, to the extent necessary to comply with the terms of agreements with Third Parties existing as of the Effective Date pursuant to which such Party first obtains rights to such Party’s Licensed Technology, which is (sub)licensed to the other Party hereunder, or (iii) to the extent previously made publicly available pursuant to this Section 5.3, or (iv) to the extent required by applicable Law or the applicable rules of any public stock exchange upon which the stock of such Party or its Affiliate is listed; provided, however, that if a Party is required by Law or the applicable rules of any public stock exchange to make any such disclosure of the terms or conditions of this Agreement, it will give reasonable advance notice to the other Party of such disclosure requirement and will use its reasonable efforts to seek confidential treatment of such terms and conditions. In addition to the foregoing, with respect to complying with the disclosure requirements of the SEC or similar regulatory bodies or the rules of an applicable public stock exchange, in connection with any required filing of this Agreement, the Parties shall consult with one another concerning which terms of this Agreement shall be requested to be redacted in any public disclosure of the Agreement (including by allowing the other Party an opportunity to review and comment upon the proposed filing of this Agreement). If time does not permit such discussion, or if after such discussion between counsel, the Party desiring to make the disclosure still believes such Party is required by applicable Law or applicable stock exchange rule to make such disclosure, it may do so, upon written notice to the other Party. For clarity, nothing in this Section 5.3 shall prevent any Party from making disclosures required by applicable Law.

5.4 Subsequent Disclosures. Once a publication or other disclosure has been made in accordance with Section 5.3 above, a Party may make subsequent disclosures of information contained therein without approval or prior review of the other Party; provided, however, that the requirements of Section or 5.3 shall, to the extent applicable, apply with respect to new or additional information in any such subsequent disclosure.

ARTICLE 6

REPRESENTATIONS, WARRANTIES AND COVENANTS

6.1 Mutual Representations, Warranties and Covenants. Each Party (the “Representing Party”) hereby represents, warrants and covenants to the other Party, as a material inducement for such other Party’s entry into this Agreement, as follows:

6.1.1 The Representing Party is duly organized and validly existing under the Laws of its jurisdiction of incorporation and it has full corporate power and authority and has taken all corporate action necessary to enter into and perform this Agreement;

6.1.2 This Agreement is a legal and valid obligation binding upon the Representing Party and enforceable against it in accordance with its terms, assuming due execution and delivery of the Agreement by the Parties, and subject to applicable laws regarding insolvency, bankruptcy, reorganization, moratorium and other Laws affecting creditors’ rights generally as from time to time in effect;

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6.1.3 The execution, delivery and performance of the Agreement by the Representing Party does not conflict with any agreement, instrument or understanding, oral or written, by which it is bound, nor to its knowledge, violate any Law;

6.1.4 To its knowledge as of the Effective Date, no government authorization, consent, approval, license, exemption of or filing or registration with any court or governmental department, commission, board, bureau, agency or instrumentality, domestic or foreign, under any applicable laws, rules or regulations currently in effect, is or will be necessary for the granting of the licenses set forth in this Agreement, or for the performance by the Representing Party of its obligations under this Agreement; and

6.1.5 The Representing Party has not granted as of the Effective Date, and during the Term will not grant, any right to any Third Party relating to its respective Patents, Know-How or Materials licensed hereunder which conflicts with the rights granted to the other Party hereunder; and without limiting the foregoing, the Representing Party will not, during the Term, encumber the Patents, Know-How and Materials licensed to the other Party hereunder, with liens, mortgages, security interests or another similar interest that would give the holder the right to convert the interest into ownership of such Patents, Know-How and//or Materials, unless the encumbrance is subject to the licenses and rights granted to the other Party herein.

6.2 Representations, Warranties and Covenants by Maxygen. Maxygen hereby represents and warrants and covenants to CPC as follows:

6.2.1 It has sufficient legal and/or beneficial title, ownership or license, free and clear from any Encumbrances (as defined in the Master Joint Venture Agreement), of the Licensed Technology to grant the licenses to CPC set forth in this Agreement on the terms and conditions herein. For clarification purposes, the representation and warranty in this Section 6.2.1 applies to the ownership or licensure of the Licensed Technology and shall have no effect as to the “AS IS” disclaimer, and disclaimers regarding validity, enforceability or non-infringement, with respect to the Licensed Technology in Section 6.4;

6.2.2 During the Term of this Agreement, it shall not enter into any agreement with any Third Party, nor grant any license or covenant not to sue, or other similar interest or benefit, exclusive or otherwise, to any Third Party, relating to any Licensed Technology that conflicts with the licenses to CPC set forth in this Agreement on the terms and conditions herein;

6.2.3 As of the Effective Date, (i) Exhibits 1.10.3, 1.16.3, 1.39.3, collectively, are a complete and accurate list of all Patents within the Licensed Technology which are either (A) owned by Maxygen, or (B) to the extent such information is available in the records of Maxygen without duty of inquiry, licensed to Maxygen under the Third Party Agreements;

6.2.4 As of the Effective Date, (i) Maxygen is not in material breach of any of its Third Party Agreements and no Third Party has notified Maxygen of any material breach of such

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Third Party Agreements, in each case that remains uncured and which would result in a material adverse effect on the ability of Maxygen to perform its obligations hereunder, and (ii) Maxygen has not received written notice from any licensor under a Third Party Agreement purporting to terminate, or restrict the scope of, Maxygen’s rights under such Third Party Agreement with respect to the scope of the rights licensed to CPC hereunder by reason of any action or omission of Maxygen;

6.2.5 As of the Effective Date, except as set forth on Exhibit 6.2.5, neither Maxygen nor any of its Affiliates has received written notice or written claim of infringement from any Third Party alleging that the activities of Maxygen or any of its Affiliates in practicing the Licensed Technology infringe, misappropriate, or otherwise unlawfully use proprietary rights, including Patents, copyrights or trade secrets (but excluding trademark rights);

6.2.6 Except as set forth on Exhibit 6.2.6, to the Knowledge (as defined in the Master Joint Venture Agreement) of Maxygen as of the Effective Date, (i) no written claim by any Third Party contesting the validity or enforceability of the Patents within the Licensed Technology, or use or ownership of the Licensed Technology, has been received by Maxygen, and (ii) there is no pending (i.e., filed or requested) interference or litigation that involves any of the Patents within the Licensed Technology;

6.2.7 During the Term of the Agreement, Maxygen will comply with all applicable terms and conditions under the Third Party Agreements and the New Third Party Agreements and will not terminate, amend, or waive any rights under any Third Party Agreement or any New Third Party Agreement in any manner (a) which diminishes the licenses to CPC or requires any increase in obligations by CPC hereunder with respect to the Licensed Technology that is subject to such Third Party Agreement or New Third Party Agreement, as applicable, (b) that requires any increase in obligations by Astellas under the Astellas Agreement, or (c) impairs CPC’s ability to perform its obligations under, or grant the licenses to Astellas under, the Astellas Agreement;

6.2.8 The list of Third Party software set forth in Exhibit 2.1.5 (x) is a complete list of Third Party software (i) needed to run the Software, or (ii) used by Maxygen in the conduct of the scientific and technical activities of the Business (as defined under the Asset Contribution Agreement); (y) is generally available for license by CPC as of the Effective Date, and (z) can be licensed by CPC at an aggregate cost (based on prices as of the Effective Date) that does not exceed one hundred thousand dollars ($100,000);

6.2.9 Except as may be expressly provided under the Third Party Agreements listed on Exhibit 1.46, no Person who has licensed Patents within the Licensed Technology to Maxygen, has ownership rights or license rights to improvements made by Maxygen in such Licensed Technology;

6.2.10 Maxygen has the full right to grant the licenses and sublicenses to be granted to CPC in accordance with Section 2.1 and the terms and conditions hereof, and there exist no restrictions on sublicensing any intellectual property licensed to Maxygen which would otherwise fall within the full scope of such license and sublicense to CPC as set forth and in accordance with the terms and conditions of this Agreement in the absence of such restriction; and

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6.2.11 Except with respect to annual payments, milestone payments, royalties on product sales, or other similar payments under Third Party Agreements indicated on Exhibit 2.5.1, or as provided in Third Party Agreements listed on Exhibit 1.46 with respect to indemnity obligations or the sharing of costs and/or recoveries in connection with enforcement or defense of Patents, there are no royalties, fees, honoraria or similar payments payable by Maxygen to any Third Person arising from the grant or practice of a sublicense to CPC.

6.3 Representations, Warranties and Covenants by CPC. CPC hereby represents and warrants and covenants to Maxygen as follows:

6.3.1 It has sufficient legal and/or beneficial title, ownership or license, free and clear from any Encumbrances (as defined in the Master JVA) other than applicable terms and conditions of Contributor Contracts assigned to CPC pursuant to the Asset Contribution Agreement, of the CPC Improvements and CPC Other Improvements to grant the licenses and covenants not to sue set forth in Sections 4.5.2 and 6.3.5 of this Agreement on the terms and conditions herein. For clarification purposes, the representation and warranty in this Section 6.3.1 applies to the ownership or licensure of the CPC Improvements and CPC Other Improvements and shall have no effect as to the “AS IS” disclaimer, and disclaimers regarding validity, enforceability or non-infringement, with respect to the CPC Improvements and CPC Other Improvements in Section 6.4;

6.3.2 During the Term of this Agreement, it shall not grant any assignment, license, covenant not to sue, or other similar interest or benefit, exclusive or otherwise, to any Third Party relating to any Patent, Material, Know-How or other proprietary right that conflicts with the licenses and covenants not to sue with respect to the CPC Improvements and CPC Other Improvements in Sections 4.5.2 and 6.3.5 of this Agreement on the terms and conditions herein;

6.3.3 CPC and its Affiliates shall not purport to sublicense, or otherwise facilitate any Third Party’s use of, the Enabling Technology or Software prior to consummation of a CPC Change of Control without the prior written consent of Maxygen except as expressly provided for under Section 2.2.

6.3.4 Until the expiration of the Enabling Patents in the Territory, on a patent-by-patent and country by country basis, CPC shall not, and shall cause its Affiliates not to, practice the Enabling Technology in or for any use outside the Field, and CPC shall not develop, commercialize or otherwise exploit any Resulting Products in or for any use outside the Field, except in each case to the extent that CPC has received a license or sublicense under the Enabling Technology from a Third Party capable of granting such license or sublicense covering such practice or development, commercialization or other exploitation outside the Field. CPC acknowledges that practice of the Enabling Technology for any use outside the Field without such license or sublicense, may result in damage to Maxygen or its Affiliates, which may include loss of license rights to Enabling Technology under Third Party Agreements or monetary damages.

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6.3.5 For so long as CPC remains an Affiliate (as defined under the Bayer Agreement) of Maxygen, CPC will not, and shall cause each of its Affiliates not to, sue Bayer HealthCare LLC (or its successor in interest), or its Affiliate for use of the Enabling Technology (substantially as such Enabling Technology was practiced by Maxygen prior to the Effective Date of the Bayer Agreement) under any Patents that issue to (as “issued to” is construed under the Bayer Agreement) CPC or its Affiliates after the Effective Date claiming any improvements, modifications, enhancements or changes to the Enabling Technology which are directed to the practice of the Enabling Technology per se, but excluding without limitation any Patents directed to any specific Resulting Products (“CPC Improvements”).

6.3.6 CPC covenants that it and its Affiliates shall not, and shall not permit any Third Party to which CPC or its Affiliate transfers any CMVP Materials or materials derived therefrom to, use the CMVP Materials or other materials derived therefrom for any use other than as research reagents. The covenant in this Section 6.3.6 shall not be construed to prohibit other uses by CPC or its Affiliates of CMV promoter variants separately synthesized by CPC or its Affiliates or Third Parties without use of the tangible CMVP Materials provided by Maxygen or other tangible materials directly derived therefrom.

6.3.7 CPC acknowledges that certain Patents, Know-How and Materials within the Licensed Technology have been or may be licensed to Maxygen or its Affiliates pursuant to the Third Party Agreement(s) listed on Exhibit 1.46, and that the sublicenses granted by Maxygen or its Affiliates to CPC with respect thereto are subject and subordinate to the terms of any such Third Party Agreement. CPC hereby covenants that CPC shall, for the lesser of the term of each such Third Party Agreement or any New Third Party Agreement and the term of this Agreement, comply with all applicable restrictions and obligations applicable to sublicensees set forth in the terms of each such Third Party Agreement in the form provided as of the Effective Date and any such New Third Party Agreement in the form provided pursuant to Section 2.5.2 regarding the use of the Licensed Technology to which such Third Party Agreement or such New Third Party Agreement, as applicable, relates, and all applicable restrictions (if any) with respect to Resulting Products; provided, however, it shall not be considered a breach of this covenant by CPC to the extent any failure to comply by CPC arises from Maxygen’s breach of its covenants in Section 6.2.7.

6.3.8 For so long as CPC remains an Affiliate (as defined under the Bayer Agreement) of Maxygen, CPC shall comply, and shall ensure that its Affiliates comply, with applicable terms and conditions set forth in the Third Party Agreements listed on Exhibit 1.46. For so long as CPC remains an Affiliate (as defined under the Bayer Agreement) of Maxygen, CPC shall not purport to terminate or amend any Third Party Agreement in any manner which would diminish the license to Bayer, or require any increase in obligations of Bayer, under the Bayer Agreement with respect to the Licensed Technology that is subject to such Third Party Agreement without Maxygen’s prior written consent.

6.3.9 For so long as CPC remains an Affiliate (as defined under the Bayer Agreement) of Maxygen, CPC shall notify both Maxygen and Bayer HealthCare LLC promptly if CPC receives notice, whether or not there is a cure period, from a Third Party that CPC, or Maxygen or any other licensee of Maxygen, is in material breach of any Third Party Agreement, or notice from any Third Party which purports to modify or terminate any Third Party Agreement in any manner. CPC shall take prompt and commercially reasonable steps to cure any such breach by CPC or its Affiliate.

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6.3.10 Until the earlier of (a) the Option Closing and (b) July 2, 2013, CPC shall ensure that it and its Subsidiaries do not (1) themselves or on behalf of others, acquire, develop, make, use, sell, import, offer to sell or commercialize any Coagulation Factor Variant, nor (2) grant or attempt to grant any Third Party a license to do so. As used herein, “Coagulation Factor Variant” means (i) any amino acid (including any natural, synthetic, modified or other amino acid analogue) chain that is any of coagulation Factor VII, coagulation Factor VIII or coagulation Factor IX, or any variant, homolog, derivative, mutant, or fragment of Factor VII, Factor VIII or Factor IX, or any of the foregoing that is conjugated or otherwise coupled to any other molecule (e.g., polyethylene glycol, immunoglobulin domain, sialylation, pegylated, or glycosylation).

6.3.11 For so long as CPC remains an Affiliate (as defined under the Bayer Agreement) of Maxygen, CPC shall comply, and shall ensure that its Subsidiaries comply, with the applicable terms and conditions set forth in the various agreements entered into by and between Maxygen, Inc. and Bayer HealthCare LLC, on or about July 1, 2008, that (i) apply by their terms to Affiliates of Maxygen or (ii) provide that Maxygen shall cause, require, ensure or otherwise procure performance or compliance by its Affiliates, including the following provisions: Sections 3.1, 4.4(c)(i), 4.4(d)(i), 4.4(d)(ii), 4.4(d)(iii), 4.4(d)(v), 4.4(d)(vii), 6.3 and 11.5 of the Technology Transfer Agreement; Section 7.1.1 of the License Agreement (also referred to in this Agreement as the “Bayer Agreement”); and Sections 6.2 and 8.3 of the Intellectual Property Cross License Agreement.

6.4 Disclaimer of Warranties. EXCEPT EXPRESSLY AS SET FORTH IN THIS AGREEMENT, THE ENABLING TECHNOLOGY, SOFTWARE, IN-LICENSED PROGRAM-SPECIFIC TECHNOLOGY, RR TECHNOLOGY, CMVP TECHNOLOGY, ASTELLAS AGREEMENT TECHNOLOGY, OTHER PROGRAM TECHNOLOGY, CONTRIBUTOR TECHNOLOGY, CPC IMPROVEMENTS OR CPC OTHER IMPROVEMENTS HEREUNDER, AND ALL PATENTS, KNOW-HOW AND MATERIALS WITHIN THE FOREGOING, ARE PROVIDED AND LICENSED TO CPC OR MAXYGEN, AS APPLICABLE, “AS IS.” EXCEPT EXPRESSLY AS SET FORTH IN THIS AGREEMENT, MAXYGEN AND CPC EXPRESSLY DISCLAIM ANY AND ALL WARRANTIES OR CONDITIONS, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, WITH RESPECT TO ANY OF THE ENABLING TECHNOLOGY, SOFTWARE, IN-LICENSED PROGRAM-SPECIFIC TECHNOLOGY, RR TECHNOLOGY, CMVP TECHNOLOGY, ASTELLAS AGREEMENT TECHNOLOGY, OTHER PROGRAM TECHNOLOGY, OR CPC IMPROVEMENTS, CPC OTHER IMPROVEMENTS OR CONTRIBUTOR TECHNOLOGY, OR RESULTS OBTAINED, OR COMPOUNDS OR PRODUCTS, IF ANY, DEVELOPED, CREATED OR PRODUCED IN WHOLE OR PART THROUGH APPLICATION OF THE LICENSED TECHNOLOGY OR ANY OTHER SUBJECT MATTER OF THIS AGREEMENT, INCLUDING ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, BOTH PARTIES ACKNOWLEDGE AND DISCLAIM ANY WARRANTY AS TO THE USEFULNESS OR COMMERCIAL SUCCESS OF ANY RESULTING PRODUCT, COMPOUND OR OTHER PRODUCT OR THE ACHIEVEMENT OF DESIRED GOALS THROUGH USE OF THE LICENSED TECHNOLOGY.

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ARTICLE 7

INDEMNIFICATION

7.1 Indemnification.

7.1.1 Fault-Based.

(a) Subject to Sections 7.2 and 7.3, CPC shall defend, indemnify, and hold Maxygen, its Affiliates, and their respective directors, officers, employees and agents (collectively, “Maxygen Indemnitees”) harmless, at CPC’s cost and expense, from and against any and all liabilities, losses, costs, damages, fees or expenses (including reasonable legal expenses and attorneys’ fees incurred by any Maxygen Indemnitees until such time as CPC has acknowledged and assumed its indemnification obligation hereunder with respect to a claim) payable to a Third Party (collectively, “Losses”) arising out of any claim, action, lawsuit, or other proceeding (collectively, “Claims”) brought against any Maxygen Indemnitee by such Third Party to the extent such Losses result from (i) the breach by CPC of any covenant set forth in Sections 6.3.4, 6.3.5, 6.3.6, 6.3.8, 6.3.9, 6.3.10 or (ii) CPC’s, or any of its Affiliates’ or licensees’ or sublicensees’, use, testing, operation, sale, manufacture or other exploitation of the Licensed Technology or any Compounds or Products that CPC or any of its Affiliates discovers, develops, creates, modifies or manufactures using any Licensed Technology, including the Resulting Products (each of (i) or (ii), a “Fault of CPC” for purposes of this Article 7); but excluding such Losses to the extent they arise from the Fault of Maxygen, arise from any Claim alleging infringement of intellectual property rights of a Third Party or arise from the gross negligence, recklessness or willful misconduct of Maxygen or any of its Affiliates.

(b) Subject to Sections 7.2 and 7.3, Maxygen shall defend, indemnify, and hold CPC, its Affiliates, and their respective directors, officers, employees and agents (collectively, “CPC Indemnitees”) harmless, at Maxygen’s cost and expense, from and against any and all Losses (including reasonable legal expenses and attorneys’ fees incurred by any CPC Indemnitees until such time as Maxygen has acknowledged and assumed its indemnification obligation hereunder with respect to a claim) arising out of any Claim brought against any CPC Indemnitee by such Third Party to the extent such Losses result from (i) a breach by CPC of its representations or warranties set forth in Section 6.1 or 6.2, or (ii) claims that any exclusive license under the Enabling Technology previously granted to such Third Party by Maxygen or its Affiliates prevents the grant of the license to CPC under Enabling Technology for the research, development, manufacture or commercialization of Compounds and Products in the Field on the terms and conditions set forth herein or, (iii) Maxygen’s, or any of its Affiliates’ or licensee’s or sublicensees’, use, testing, operation, sale manufacture or other exploitation of the Licensed Technology or Contributor Technology or products or technology that Maxygen or any of its Affiliates discovers, develops, creates, modifies or manufactures using the Licensed Technology or Contributor Technology, including the Resulting Products (each of (i), (ii) or (iii), a “Fault of Maxygen” for purposes of this Article 7); but excluding such Losses to the extent they arise from the Fault of CPC, arise from any Claim alleging infringement of intellectual property rights of a Third Party or arise from the gross negligence, recklessness or willful misconduct of CPC or any of its Affiliates.

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7.1.2 Apportionment of Fault. If any Losses occur by reason of or result from the joint Fault of CPC and Fault of Maxygen, liability for such Losses under Section 7.1.1(a) or Section 7.1.1(b) shall be apportioned between CPC and Maxygen according to the percentage of Fault of CPC and Maxygen. This Section 7.1.2 shall apply even under circumstances where a Third Party bears a percentage of the fault.

7.2 Claim for Indemnification. Whenever any Claim shall arise for indemnification under Article 7, the Maxygen Indemnitees and the CPC Indemnitees entitled to indemnification (the “Indemnified Party”) shall promptly notify the other Party (the “Indemnifying Party”) in writing of the Claim and, when known, the facts constituting the basis for the Claim. The Indemnified Party’s failure to notify the Indemnifying Party will not relieve the Indemnifying Party from any liability to such Indemnified Party except to the extent any liability results from the failure to timely notify the Indemnifying Party. The Indemnifying Party shall promptly assume, and have the right to control, the defense and settlement thereof at its own expense. The Indemnified Party shall not settle or compromise any Claim by a Third Party for which it is entitled to indemnification without the prior written consent of the Indemnifying Party, unless the Indemnifying Party is in breach of its obligation to defend hereunder. In no event shall either the Indemnified Party or Indemnifying Party settle any Claim without the prior written consent of the Indemnified Party if such settlement does not include a release from liability on such Claim or if such settlement would involve undertaking an obligation other than the payment of money by the settling Party that would bind or impair the non-settling Party, or result in any Licensed Technology, Patent or trademark of the other Party being rendered invalid or unenforceable, or if such settlement contains an admission that any Licensed Technology, Patent or trademark of the other Party is invalid or unenforceable. The provisions of this Article 7 shall be subject to the dispute resolution procedures of Article 9.

7.3 Reduction of Indemnity Payments. Notwithstanding anything in this Article 7 to the contrary, an indemnity payment owed by one Party to the other Party pursuant to this Agreement shall be reduced by all amounts actually received by the Indemnified Party under insurance policies purchased and maintained by the Indemnifying Party in connection with the Claim for which the indemnification related (less all deductibles, costs of collection, and other expenses incurred in connection therewith).

ARTICLE 8

TERM AND TERMINATION

8.1 Term. This Agreement will commence upon the Effective Date and shall be perpetual thereafter (the “Term”).

8.2 Expiration of Patents. On the expiration of each Patent within the Licensed Technology, on a Patent-by-Patent and country-by-country basis, the license set forth herein to the invention claimed in such Patent shall become non-exclusive in such country.

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8.3 CPC Breach of Obligations With Respect to a Third Party Agreement. If CPC or any of its Affiliates materially breaches or materially fails to comply with any of the obligations or requirements expressly provided for hereunder with respect to any Third Party Agreement or New Third Party Agreement pursuant to which Maxygen obtains rights or licenses to Patents, Know-How or Material (provided that the substance of such obligation or requirement, and/or the applicable terms and conditions of such agreement setting forth such obligation or requirement, have been disclosed to CPC), and after notice to CPC from the licensor or Maxygen of such breach CPC fails to cure such breach within the period for cure provided in the applicable Third Party Agreement or New Third Party Agreement, then Maxygen shall have the right upon written notice to CPC to terminate CPC’s sublicense granted hereunder with respect to the Patents, Know-How or Materials sublicensed under such Third Party Agreement or New Third Party Agreement, as applicable; provided, however, that that the foregoing shall not apply to the extent the material breach or material failure to comply is attributable to a breach by Maxygen of Section 6.2.7 with respect to the applicable term or condition of such Third Party Agreement or such New Third Party Agreement, as applicable.

8.4 Cooperation Following Certain Terminations of Third Party Agreements.

8.4.1 Third Party Termination for Cause. In the event that the rights of Maxygen under any Third Party Agreement are terminated by the Third Party for cause thereunder in a manner which would diminish the licenses to CPC hereunder with respect to the Licensed Technology that is subject to such Third Party Agreement, and provided that CPC and its Affiliates are not in material breach of this Agreement, and have not failed to comply with any material obligations under such Third Party Agreement, then Maxygen shall use its reasonable efforts to cooperate with efforts of CPC to assure that CPC can maintain its sublicense to such Third Party Agreement.

8.4.2 Express Survival of Sublicenses. In the event that the rights of Maxygen under any Third Party Agreement are terminated by the Third Party thereunder in a manner which would diminish the licenses to CPC hereunder with respect to the Licensed Technology that is subject to such Third Party Agreement and such Third Party Agreement provides the express right for the sublicense granted to CPC hereunder to survive such termination, Maxygen shall use its reasonable efforts to take such actions required by such Third Party Agreement as may be required to ensure that the sublicense granted hereunder shall survive, unless the rights of Maxygen under such Third Party Agreement were terminated as a result of CPC’s, or its Affiliate’s or sublicensee’s, breach or failure to comply with the terms and conditions of such Third Party Agreement.

ARTICLE 9

DISPUTE RESOLUTION

9.1 Negotiation of CEOs. If any dispute arises between the Parties out of or in connection with this Agreement, or the validity, enforceability, construction, performance or breach (or alleged breach) thereof (a “Dispute”), either Party may, by written notice to the other, have such dispute referred to the CEOs (or an executive officer designated by the CEO with authority to settle such dispute) of the Parties for attempted resolution by good faith negotiations within ten (10) Business Days. In such event, each Party shall cause its CEO or the CEO’s designated executive officer to meet and be available to attempt to resolve such issue. If the Parties should resolve such

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dispute or claim, a memorandum setting forth their agreement will be prepared and signed by both Parties if requested by either Party. The Parties shall cooperate in an effort to limit the issues for consideration in such manner as narrowly as reasonably practicable in order to resolve the dispute. The Parties agree first to try in good faith to settle or resolve Disputes through the procedure described in this Section 9.1 before initiating arbitration pursuant to Section 9.2 or resorting to other legal action pursuant to Section 9.3 or 9.4.

9.2 Arbitration. Except with respect to Disputes involving the intellectual property rights of a Party under Section 9.3, the Parties agree that any Dispute which is not resolved under Section 9.1, or as otherwise expressly provided herein, shall be finally settled by binding arbitration under this Section 9.2 under the Rules of Conciliation and Arbitration of the International Chamber of Commerce (the “ICC Rules”) by one or more arbitrators appointed in accordance with the rules thereof and the decisions of the arbitrator shall be final and binding on the Parties hereto. The place of the arbitration proceeding shall be in San Francisco, California. The Parties agree that the decision shall be the sole, exclusive and binding remedy between them regarding determination of the matters presented to the arbitrator. The costs of such arbitration, including administrative and arbitrator’s fees, shall be shared equally by the Parties, and each Party shall bear its own expenses and attorney’s fees incurred in connection with the arbitration. The Parties shall use good faith efforts to complete arbitration under this Section 9.2 within ninety (90) days following the initiation of such arbitration. The arbitrator shall establish reasonable additional procedures to facilitate and complete such arbitration within such ninety (90) day period.

9.3 Intellectual Property Disputes. Any disputes related to intellectual property rights of the Parties which are not resolved under Section 9.1 shall be brought to a court of competent jurisdiction in the country in which such intellectual property rights were granted.

9.4 Provisional Remedies. Nothing in this Agreement shall limit the right of either Party to seek to obtain in any court of competent jurisdiction any equitable or interim relief or provisional remedy, including injunctive relief, pending resolution under Section 9.1, 9.2 or 9.3 as applicable, that may be necessary to protect the rights or property of that Party. Seeking or obtaining such equitable or interim relief or provisional remedy in a court shall not be deemed a waiver of the agreement to arbitrate. For clarity, any such equitable remedies shall be cumulative and not exclusive and are in addition to any other remedies that either Party may have under this Agreement or applicable Law.

ARTICLE 10

MISCELLANEOUS

10.1 Governing Law. This Agreement and any dispute arising from the performance or breach hereof shall be governed by and construed and enforced in accordance with the substantive Laws of the State of New York, without reference to conflicts of laws principles. Notwithstanding the above, any dispute regarding validity or enforceability of any Patent shall be governed by the patent laws of the jurisdiction in which such Patent was issued solely for the purpose of resolution of the dispute as to validity and enforceability.

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10.2 Assignment. This Agreement shall not be assignable or otherwise transferred, in whole or in part, by either Party to any Third Party without the written consent of the other Party. Notwithstanding the foregoing, (i) CPC may assign this Agreement, without the written consent of Maxygen, to (a) an entity that acquires all or substantially all of the assets and business of CPC to which this Agreement relates in connection with a CPC Change of Control, or (b) if Astellas has exercised the Buy-Out Option, to an Affiliate of CPC or Astellas, in each case provided that the assignee promptly agrees in writing to be bound by the terms and conditions of this Agreement (including the licenses to Maxygen hereunder with respect to the Contributor Technology, if any, acquired by such entity); and (ii) Maxygen may assign this Agreement, without the written consent of CPC, to an entity that acquires (x) all or substantially all of the business or assets (which shall in each case shall include the Licensed Technology) of Maxygen to which this Agreement pertains (whether by merger, reorganization, acquisition, sale or otherwise), or (y) all or substantially all of the Enabling Technology, in each case provided that the assignee promptly agrees in writing to be bound by the terms and conditions of this Agreement (including the licenses to CPC hereunder with respect to the Licensed Technology, if any, acquired by such entity). No assignment or transfer of this Agreement shall be valid and effective unless and until the assignee/transferee agrees in writing to be bound by the provisions of this Agreement. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the Parties. Except as expressly provided in this Section 10.2, any attempted assignment or transfer of this Agreement shall be null and void.

10.3 Limitation on Liability. EXCEPT FOR BREACH OF ARTICLE 5, IN NO EVENT SHALL EITHER PARTY OR ITS AFFILIATES BE LIABLE TO THE OTHER PARTY FOR ANY LOSS OF PROFITS, LOSS OF BUSINESS OR INTERRUPTION OF BUSINESS, OR FOR ANY OTHER INDIRECT, SPECIAL, INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES OF ANY KIND, EVEN IF SUCH PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSS OR DAMAGES. IN NO CASE SHALL EITHER PARTY BE LIABLE FOR ANY REPRESENTATION OR WARRANTY MADE BY THE OTHER PARTY TO ANY THIRD PARTY. NOTHING IN THIS SECTION 10.3 IS INTENDED TO LIMIT EITHER PARTY’S OBLIGATIONS UNDER ARTICLE 7 IN RELATION TO AMOUNTS PAID TO A THIRD PARTY.

10.4 Notices. Any notice, request, delivery, approval or consent required or permitted to be given under this Agreement shall be in English language, in writing, shall specifically refer to this Agreement and shall be deemed to have been sufficiently given if delivered in person, transmitted by as a PDF attachment to an email (with response email confirming receipt) or by express courier service (signature required) or five (5) Business Days after it was sent by registered letter, return receipt requested (or its equivalent), provided that no postal strike or other disruption is then in effect or comes into effect within two (2) Business Days after such mailing, to the Party to which it is directed at its address or email address shown below or such other address or email address as such Party will have last given by notice to the other Party.

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If to Maxygen,
addressed to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
with a copy to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: General Counsel
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
and a copy to:	Wilson Sonsini Goodrich & Rosati
	Professional Corporation
	650 Page Mill Road
	Palo Alto, CA 94304-1050
	USA
	Attention: David W. Stevens
	Telephone: (650) 493-9300
If to CPC, addressed to:	Perseid Therapeutics LLC c/o Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
with a copy to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: General Counsel
	Telephone: (650) 298-5300
	Email address: corporatesecretary@maxygen.com
and a copy to:	Wilson Sonsini Goodrich & Rosati
	Professional Corporation
	650 Page Mill Road
	Palo Alto, CA 94304-1050
	USA
	Attention: David W. Stevens
	Telephone: (650) 493-9300

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10.5 Waiver. Neither Party may waive or release any of its rights or interests in this Agreement except in writing. The failure of either Party to assert a right hereunder or to insist upon compliance with any term or condition of this Agreement shall not constitute a waiver of that right or excuse a similar subsequent failure to perform any such term or condition. No waiver by either Party of any condition or term in any one or more instances shall be construed as a continuing waiver of such condition or term or of another condition or term.

10.6 Severability. If any provision hereof is held invalid, illegal or unenforceable by any arbitrator or court of competent jurisdiction from which no appeal can be or is taken, the Parties shall negotiate in good faith a valid, legal and enforceable substitute provision that most nearly reflects the original intent of the Parties and all other provisions hereof shall remain in full force and effect in such tribunal or jurisdiction, as the case may be, and shall be liberally construed in order to carry out the intentions of the Parties as nearly as may be possible. Such invalidity, illegality or unenforceability shall not affect the validity, legality or enforceability of such provision in any other tribunal or jurisdiction.

10.7 Entire Agreement/Modification. This Agreement, including its Exhibits, and the Transaction Agreements (as defined in the Master Joint Venture Agreement by and between Maxygen, CPC and Astellas of even date herewith (the “Master Joint Venture Agreement”) set forth all the covenants, promises, agreements, warranties, representations, conditions and understandings between the Parties with respect to the subject matter hereof and thereof, and supersede all prior agreements and understandings between the Parties with respect to such subject matter. No subsequent alteration, amendment, change or addition to this Agreement shall be binding upon the Parties unless reduced to writing and signed by the respective authorized officers of each of the Parties.

10.8 Relationship of the Parties. The Parties agree that the relationship of CPC and Maxygen established by this Agreement is that of independent contractors. Furthermore, the Parties agree that this Agreement does not, is not intended to, and shall not be construed to, establish an employment, agency, joint venture, partnership or any other relationship. Except as may be specifically provided herein, neither Party shall have any right, power or authority, nor shall they represent themselves as having any authority to assume, create or incur any expense, liability or obligation, express or implied, on behalf of the other Party, or otherwise act as an agent for the other Party for any purpose.

10.9 Force Majeure. Except with respect to payment of money, neither Party shall be liable or responsible to the other Party nor be deemed to have defaulted under or breached this Agreement for failure or delay in fulfillment or the performance of any of its obligations under this Agreement for the time and to the extent such failure or delay is caused by or results from fire, earthquake, tornado, embargo, prohibition or intervention, riot, civil commotion, war, act of war (whether war be declared or not), insurrection, terrorist act, strike, flood, governmental act or restriction (beyond the reasonably control of the respective Party), act of God, or other cause that is beyond the reasonable control and not caused by the negligence or misconduct of the affected Party. The Party affected by such force majeure will provide the other Party with full particulars thereof as

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soon as it becomes aware of the same (including its best estimate of the likely extent and duration of the interference with its activities), and will use commercially reasonable efforts to overcome the difficulties created thereby and to resume performance of its obligations as soon as practicable. If the performance of any such obligation under this Agreement is delayed owing to such a force majeure for any continuous period of more than one hundred eighty (180) days, the Parties hereto will consult with respect to an equitable solution, including the possibility of the mutual termination of this Agreement.

10.10 Third Party Beneficiaries. Except for the rights to indemnification provided for a Party’s indemnitees pursuant to Article 7, all rights, benefits and remedies under this Agreement are solely intended for the benefit of CPC and Maxygen, and except for such rights to indemnification expressly provided pursuant to Article 7, no Third Party shall have any rights whatsoever to (i) enforce any obligation contained in this Agreement (ii) seek a benefit or remedy for any breach of this Agreement, or (iii) take any other action relating to this Agreement under any legal theory, including but not limited to, actions in contract, tort (including but not limited to negligence, gross negligence and strict liability), or as a defense, setoff or counterclaim to any action or claim brought or made by the Parties.

10.11 Advice of Counsel. Maxygen and CPC each acknowledge that this Agreement is the result of informed negotiation as part of a larger transaction between sophisticated parties, and each expressly agree that any rule of contract construction which might otherwise apply to cause ambiguities to be resolved against the drafting Party shall not apply to this Agreement, nor to any exhibits or attachments to this Agreement.

10.12 Other Obligations. Except as expressly provided in this Agreement or as separately agreed upon in writing between Maxygen and CPC, each Party shall bear its own costs incurred in connection with the implementation of the obligations under this Agreement.

10.13 Further Assurances. At any time or from time-to-time on and after the Effective Date, a Party shall at the request of the other Party (i) deliver to the requesting Party such records, data or other documents as may be reasonably necessary to give effect to the provisions of this Agreement, (ii) execute, and deliver or cause to be delivered, all such consents, documents or further instruments of assignment, transfer or license as may be reasonably necessary to give effect to the provisions of this Agreement, and (iii) take or cause to be taken all such actions, as the requesting Party may reasonably deem necessary or desirable in order for the requesting Party to obtain the full benefits of this Agreement and the transactions contemplated hereby.

10.14 Governmental Matters.

10.14.1 Governmental Filings. Subject to Section 5.3, to the extent, if any, that a Party concludes in good faith that it is required to file or register this Agreement or a notification thereof with any governmental authority, including without limitation the SEC and the Competition Directorate of the Commission of the European Communities, in accordance with applicable Laws and regulations, such Party may do so, and the other Party shall cooperate in such filing or notification and shall execute all documents reasonable required in connection therewith, at the expense of the requesting Party. The Parties shall promptly notify each other as to the activities or inquires of any such governmental authority relating to this Agreement, and shall cooperate, to respond to any request for further information therefrom at the expense of the requesting Party.

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10.14.2 License Registrations. CPC may, at its expense, register the licenses granted under this Agreement in any country of, or community or association of countries in, the Territory. Maxygen shall reasonably cooperate in such registration at CPC’s expense. Upon request by CPC, Maxygen agrees promptly to execute any “short form” licenses developed in a form reasonably acceptable to both Maxygen and CPC and reasonably submitted to it by CPC from time to time in order to effect the foregoing registration in such country. No such “short form” license shall be deemed to amend or be used to interpret this Agreement. If there is any conflict between such a license or other recordation document and this Agreement, this Agreement shall control.

10.15 Counterparts. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together, shall constitute one and the same instrument.

10.16 Licenses of “Intellectual Property”. The Parties agree that the licenses granted hereunder are rights in “intellectual property” within the scope of Section 101 (or its successors) of the United States Bankruptcy Code and for other similar laws. In addition, each Party, as a licensee of intellectual property rights hereunder, shall have and may fully exercise all rights available to a licensee under the United States Bankruptcy Code, including, without limitation, under Section 365(n) or its successors.

[The remainder of this page intentionally left blank intentionally; the signature page follows.]

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IN WITNESS WHEREOF, the Parties have executed this Agreement in duplicate originals by their duly authorized representatives as of the Effective Date.

MAXYGEN, INC.		PERSEID THERAPEUTICS LLC
By:	/s/ Russell J. Howard	By:	/s/ Grant Yonehiro
Name:	Russell J. Howard, Ph.D.	Name:	Grant Yonehiro
Title:	Chief Executive Officer	Title:	CEO & President

EXHIBITS

Exhibit 1.10.2	CMVP Materials
Exhibit 1.10.3	CMVP Patents
Exhibit 1.16.2	Enabling Materials
Exhibit 1.16.3	Enabling Patents
Exhibit 1.18	Excluded Technology
Exhibit 1.19	Exclusively Out-Licensed Protein
Exhibit 1.29	MaxyBody
Exhibit 1.39.2	RR Materials
Exhibit 1.39.3	RR Patents
Exhibit 1.40	Software
Exhibit 1.46	Third Party Agreements
Exhibit 2.1.1	Prior Maxygen Licenses
Exhibit 2.1.5	Third Party Software
Exhibit 2.3.3	U.S. Government Rights
Exhibit 2.4.4	Third Party Rights
Exhibit 2.5.1	Payment Obligations
Exhibit 6.2.5	Claims
Exhibit 6.2.6	Suits

The registrant agrees to furnish to the Securities and Exchange Commission upon request a copy of any omitted schedule or exhibit.

[Signature page to Technology License Agreement]

EX-2.1.3

EXHIBIT 2.1.3

LIMITED LIABILITY COMPANY AGREEMENT

OF

PERSEID THERAPEUTICS LLC

TABLE OF CONTENTS

		Page
ARTICLE 1. DEFINED TERMS		1
Section 1.02	Interpretation	9
ARTICLE 2. GENERAL MATTERS		9
Section 2.01	Formation	9
Section 2.02	Name	10
Section 2.03	Term	10
Section 2.04	Registered Agent and Registered Office	10
Section 2.05	Principal Place of Business	10
Section 2.06	Purposes and Powers	10
Section 2.07	Books and Records	10
ARTICLE 3. MEMBERS		11
Section 3.01	Members	11
Section 3.02	Powers of Members	11
Section 3.03	Voting Rights	11
Section 3.04	Meetings and Written Consents of Members	12
Section 3.05	Liability of Members, Managers, Etc.	13
Section 3.06	Resignation	17
ARTICLE 4. NEW ISSUANCES; UNITS; CONVERSION		17
Section 4.01	New Issuances of Equity Capital	17
Section 4.02	Units	18
Section 4.03	Conversion	19
ARTICLE 5. GOVERNANCE		27
Section 5.01	Board of Managers	27
Section 5.02	Meetings and Written Consents of Board of Managers	28
Section 5.03	Committees	28
Section 5.04	Officers	29
Section 5.05	Series A Preferred Unit Protective Provisions	29
Section 5.06	Series B Preferred Unit Protective Provisions	32
ARTICLE 6. CAPITAL ACCOUNTS		34
Section 6.01	Capital Contributions	34
Section 6.02	Interest on Capital	35
Section 6.03	Limitation of Liability; Return or Withholding of Certain Distributions	35
ARTICLE 7. PROFITS AND LOSSES		35
Section 7.01	Allocations of Profits and Losses of the Company	35
Section 7.02	Allocation Adjustments to Comply with Section 704(b) of the Code	36

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TABLE OF CONTENTS

(Continued)

		Page
Section 7.03	General Provisions Regarding Allocations and Capital Account Maintenance	37
Section 7.04	Nonallocation of Distributions to Increases in Minimum Gain	38
Section 7.05	Allocation of Liabilities	38
Section 7.06	Modifications to Preserve Underlying Economic Objectives	39
Section 7.07	Withholding Taxes	39
Section 7.08	Intent of Allocations	39
ARTICLE 8. DISTRIBUTIONS; ASSETS SALES		40
Section 8.01	Distributions	40
Section 8.02	Liquidity Event Distributions	40
ARTICLE 9. DISSOLUTION; TAX MATTERS; CONVERSION TO CORPORATION		41
Section 9.01	Dissolution	41
Section 9.02	Liquidation	42
Section 9.03	Tax Matters	42
Section 9.04	Conversion to a Corporation	43
ARTICLE 10. MISCELLANEOUS		44
Section 10.01	Notices	44
Section 10.02	Delays or Omissions	46
Section 10.03	Successors and Assigns	46
Section 10.04	Severability	47
Section 10.05	Counterparts	47
Section 10.06	Entire Agreement	47
Section 10.07	Governing Law	47
Section 10.08	Jurisdiction; Venue	47
Section 10.09	Amendments	47
Section 10.10	Construction	48

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This LIMITED LIABILITY COMPANY AGREEMENT (this “Agreement”) of Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), is dated as of September 18, 2009, by and between Maxygen, Inc., a Delaware corporation (“Maxygen”) and Astellas Bio Inc., a Delaware corporation (“Bio”).

WHEREAS, the Company has been formed as a limited liability company under the Delaware Limited Liability Company Act (6 Del. C. § 18 101, et seq.), as amended from time to time (the “Delaware Act”), pursuant to the Certificate of Formation, as filed in the office of the Secretary of State of the State of Delaware; and

WHEREAS, the Initial Members desire to enter into this Agreement to set forth certain agreements relating to the ownership, management and operation of the Company.

NOW, THEREFORE, in consideration of the agreements and obligations set forth herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Members hereby agree as follows:

ARTICLE 1.

DEFINED TERMS

Unless the context otherwise requires, the terms defined in this Article 1 shall, for the purposes of this Agreement, have the meanings herein specified. All capitalized terms used and not defined herein shall have the meanings set forth in that certain Master Joint Venture Agreement (the “Joint Venture Agreement”) dated as of June 30, 2009 by and among Maxygen, Bio and Astellas Pharma Inc., a Japanese corporation.

“Additional Common Units” shall have the meaning set forth in Section 4.03(d)(i).

“Additional Member” shall have the meaning set forth in Section 3.01(b).

“Adjusted Capital Account Deficit” shall mean, with respect to any Member, the deficit balance, if any, in such Member’s Capital Account as of the end of the relevant Fiscal Year, after giving effect to the following adjustments:

(a) the Capital Account shall be increased by any amounts that such Member is obligated to restore pursuant to any provision of this Agreement or is deemed to be obligated to restore pursuant to the penultimate sentence of each of Treasury Regulations Sections 1.704-2(g)(1) and 1.704-2(i)(5); and

(b) the Capital Account shall be decreased by the items described in Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), 1.704-1(b)(2)(ii)(d)(5) and 1.704-1(b)(2)(ii)(d)(6).

The foregoing definition of Adjusted Capital Account Deficit is intended to comply with the provisions of Treasury Regulations Section 1.704-1(b)(2)(ii)(d) and shall be interpreted consistently therewith.

“Adoption Agreement” shall mean an agreement confirming the agreement of a Person to be bound by the terms and provisions of this Agreement.

“Agreement” shall have the meaning set forth in the preamble hereof.

“Annual Distribution Rate” shall mean an annual rate of $0.08 per Series A Preferred Unit and $0.08 per Series B Preferred Unit (in each case subject to adjustment from time to time for Recapitalizations as set forth elsewhere herein).

“Automatic Conversion Event” shall have the meaning set forth in Section 4.03(b).

“Bio” shall have the meaning set forth in the preamble hereof.

“Bio Manager” shall have the meaning set forth in Section 4.03(d)(i)(2).

“Board of Managers” shall have the meaning set forth in Section 5.01(a).

“Buy-Out Units” has the meaning defined in the Investors’ Rights Agreement.

“Capital Account” shall mean, for each Member, a separate account that is:

(a) increased by: (i) the amount of such Member’s Capital Contribution and (ii) allocations of Profits and other items in the nature of income and gain to such Member pursuant to Article 7;

(b) decreased by: (i) the amount of cash distributed to such Member by the Company; (ii) the fair market value as of the time of Distribution, and net of liabilities secured by such property that the Member assumes or to which the Member’s ownership of the property is subject, of any other property distributed to such Member by the Company; and (iii) allocations of Losses and other items in the nature of expenses or losses to such Member pursuant to Article 7;

(c) otherwise adjusted in accordance with the provisions of this Agreement; and

(d) revalued in connection with any event described in paragraph (a) of the definition of “Gross Asset Value” to the extent it is determined in the discretion of the Managing Member in consultation with Bio prior to the Option Expiration Date that a revaluation is necessary to preserve the economic arrangement of the Members. In determining the amount of any liability for purposes of subparagraphs (a) and (b) above, there shall be taken into account Section 752(c) of the Code and any other applicable provisions of the Code and Treasury Regulations.

Capital Accounts shall be maintained in accordance with Treasury Regulations Section 1.704-1(b) and specifically in a manner consistent with the Member’s interest in the Company, and the provisions of this Agreement shall be interpreted and applied in a manner consistent with such regulations and intent.

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“Capital Contribution” shall mean, for any Member, the sum of the net amount of cash and the fair market value as of the time of contribution, and net of liabilities secured by such property that the Company assumes or to which the Company’s ownership of the property is subject, of any other property contributed by such Member to the capital of the Company. For purposes of this Agreement, each Capital Contribution shall be deemed to have been made at the later of: (a) the Close of Business on the due date of such Capital Contribution as determined in accordance with this Agreement; or (b) the Close of Business on the date on which such Capital Contribution is actually received by the Company.

“Certificate of Formation” shall mean the Certificate of Formation of the Company and any and all amendments thereto and restatements thereof filed on behalf of the Company with the office of the Secretary of State of the State of Delaware pursuant to the Delaware Act.

“Company” shall have the meaning set forth in the preamble hereof.

“Conversion Price” shall mean $1.00 per Series A Preferred Unit and $1.00 per Series B Preferred Unit (in each case subject to adjustment from time to time for Recapitalizations and as otherwise set forth elsewhere herein).

“Conversion Rate” shall have the meaning set forth in Section 4.03(a).

“Convertible Securities” shall mean any evidences of indebtedness, shares, membership units, or other securities convertible into or exchangeable for Common Units (as such term is defined in the Voting Agreement).

“Delaware Act” shall have the meaning set forth in the preamble hereof.

“Depreciation” means, for each Fiscal Year or other period, an amount equal to the depreciation, amortization or other cost recovery deduction allowable with respect to an asset for such Fiscal Year or other period; provided, however, that if the Gross Asset Value of an asset differs from its adjusted basis for U.S. federal income tax purposes at the beginning of such Fiscal Year or other period, Depreciation shall be an amount that bears the same ratio to such beginning Gross Asset Value as the U.S. federal income tax depreciation, amortization or other cost recovery deduction with respect to such asset for such Fiscal Year or other period bears to such beginning adjusted tax basis; and provided further, that if the U.S. federal income tax depreciation, amortization or other cost recovery deduction for such Fiscal Year or other period is zero, Depreciation shall be determined with reference to such beginning Gross Asset Value using any reasonable method selected by the Managing Member and in consultation with Bio prior to the Option Expiration Date.

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“Distribution” shall mean the transfer of cash or other property without consideration whether by way of dividend or otherwise (other than dividends on Common Units payable in Common Units), or the purchase or redemption of Units by the Company for cash or property.

“Distribution Threshold” shall have the meaning set forth in Section 4.02(c).

“Equity Incentive Plan” shall mean the Company 2009 Equity Incentive Plan under which Common Units shall be reserved for current or future grant for issuance to Managers, officers, employees, and other service providers as provided therein.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.

“Excluded Opportunity” shall mean any matter, transaction or interest that is presented to, or acquired, created or developed by, or which otherwise comes into the possession of, (i) any Manager of the Company who is not an employee of the Company or any of its Subsidiaries, or (ii) any Member holding Preferred Units or any Affiliate, partner, member, director, stockholder, employee, agent or other related person of any such Member, other than someone who is an employee of the Company or any of its Subsidiaries (collectively, “Excluded Opportunity Persons”), unless such matter, transaction or interest is presented to, or acquired, created or developed by, or otherwise comes into the possession of, an Excluded Opportunity Person expressly in such Excluded Opportunity Person’s capacity as a Manager of the Company.

“Exercise Price” has the meaning defined in the Investors’ Rights Agreement.

“Fair Market Value” shall mean, as of any date prior to the expiration of the Buy-Out Option, the value of Profits Interest Units derived from the deemed value of the Company in light of the applicable Exercise Price for the Buy-Out Units, the applicable Distribution Threshold for the Profits Interest Units, the then fully-diluted capitalization of the Company, and the then liquidation preferences, participation rights and other terms and conditions of the Company’s Units and, as of the expiration of the Buy-Out Option and any date following such expiration, the fair market value of the Profits Interest Units determined in good faith by the Administrator (as defined in the Company’s 2009 Equity Incentive Plan).

“Fiscal Period” shall mean the Fiscal Year or such shorter period as necessary to take into account the Members’ varying interests in the Company.

“Fiscal Year” shall mean the fiscal year of the Company, initially the period commencing on January 1 in any calendar year and ending on December 31 in that calendar year, except as otherwise required by law, including the Code or Treasury Regulations.

“Gross Asset Value” shall mean, with respect to any asset, such asset’s adjusted basis for U.S. federal income tax purposes, except as follows:

(a) the Gross Asset Value of all Company assets shall be adjusted to equal their respective fair market values, taking Section 7701(g) of the Code into account, immediately prior to

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the following times: (i) the acquisition of an additional interest in the Company by any new or existing Member in exchange for more than a de minimis Capital Contribution; (ii) the distribution by the Company to a Member of more than a de minimis amount of Company assets as consideration for an interest in the Company; (iii) the grant of an interest in the Company (other than a de minimis interest) as consideration for the provision of services to or for the benefit of the Company by an existing Member acting in a Member capacity, or by a new Member acting in a Member capacity or in anticipation of becoming a Member; and (iv) the liquidation of the Company within the meaning of Treasury Regulations Section 1.704-1(b)(2)(ii)(g); provided, however, that adjustments pursuant to clause (i), (ii) and (iii) of this sentence shall be made only if it reasonably determined by the Managing Member in consultation with Bio prior to the Option Expiration Date that such adjustments are necessary or appropriate to reflect the relative economic interests of the Members in the Company; and

(b) the Gross Asset Value of any Company asset distributed to any Member shall be adjusted to equal the fair market value, taking Section 7701(g) of the Code into account, of such asset on the date of Distribution.

If the Gross Asset Value of an asset has been determined or adjusted pursuant to paragraph (a) or paragraph (b) above, such Gross Asset Value shall thereafter be adjusted by the Depreciation taken into account with respect to such asset for purposes of computing Profits and Losses.

“Initial Members” shall mean Maxygen and Bio.

“Lender” shall have the meaning set forth in the Bridge Loan Agreement.

“Liquidity Event” shall be deemed to be occasioned by, or to include, (a) the acquisition of the Company by another entity by means of any transaction or series of related transactions to which the Company is party (including, without limitation, any acquisition of Units reorganization, merger or consolidation but excluding any sale of Units solely for capital raising purposes) other than (i) a transaction or series of related transactions in which the holders of the voting securities of the Company outstanding immediately prior to such transaction or series of related transactions retain, immediately after such transaction or series of related transactions, as a result of Units held by such holders prior to such transaction or series of related transactions, at least a majority of the total voting power represented by the outstanding voting securities of the Company or such other surviving or resulting entity (or if the Company or such other surviving or resulting entity is a wholly-owned Subsidiary immediately following such acquisition, its parent) or (ii) the consummation of the purchase of Units pursuant to the Buy-Out Option, as such term is defined in the Investors’ Rights Agreement; (b) a sale, lease or other disposition of all or substantially all of the assets of the Company and its subsidiaries taken as a whole by means of any transaction or series of related transactions, except where such sale, lease or other disposition is to a wholly-owned Subsidiary of the Company; or (c) any liquidation, dissolution or winding up of the Company, whether voluntary or involuntary.

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“Liquidation Preference” shall mean $1.00 per Series A Preferred Unit and $1.00 per Series B Preferred Unit (in each case subject to adjustment from time to time for Recapitalizations as set forth elsewhere herein).

“Liquidation Rights” shall have the meaning set forth in Section 4.03(g).

“Loan” shall have the meaning set forth in the Bridge Loan Agreement.

“Manager” shall have the meaning set forth in Section 5.01(b).

“Managing Member” shall mean Maxygen, or its successor or assign.

“Maxygen” shall have the meaning set forth in the preamble hereof.

“Maxygen Manager” shall have the meaning set forth in Section 4.03(d)(i)(2).

“Member” shall mean any of the Initial Members and any Additional Member until such Person ceases to be a Member of the Company in accordance with the terms of this Agreement.

“Member Minimum Gain” means an amount, with respect to each Member Nonrecourse Debt, equal to the Company Minimum Gain that would result if such Member Nonrecourse Debt were treated as a nonrecourse liability, determined in accordance with Treasury Regulations Section 1.704-2(i)(3).

“Member Nonrecourse Debt” has the same meaning as the term “partner nonrecourse debt” in Treasury Regulations Section 1.704-2(b)(4).

“Member Nonrecourse Deduction” shall mean an item of loss, expense or deduction attributable to a nonrecourse liability of the Company for which a Member bears the economic risk of loss within the meaning of Treasury Regulations Section 1.704-2(i).

“Minimum Gain” of the Company or “Company Minimum Gain” shall, as provided in Treasury Regulations Section 1.704-2, mean the total amount of gain the Company would realize for federal income tax purposes if it disposed of all assets subject to nonrecourse liability for no consideration other than full satisfaction thereof.

“Option Expiration Date” shall have the meaning set forth in the Investors’ Rights Agreement.

“Options” shall mean rights, options or warrants to subscribe for, purchase or otherwise acquire Common Units or Convertible Securities.

“Original Issue Price” shall mean $1.00 per Series A Preferred Unit and $1.00 per Series B Preferred Unit (in each case subject to adjustment from time to time for Recapitalizations as set forth elsewhere herein).

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“Percentage Interest” of any Member shall mean the product of (x) the quotient of the number of Common Units held by such Member (with the Preferred Units held by such Member being treated for this purpose as if they had been converted to Common Units at the then applicable Conversion Rate) divided by the total number of outstanding Units multiplied by (y) 100.

“Permitted Equity Offering” shall mean any offering of Units, securities linked to Units or any other equity security (including any security convertible into or exercisable for any equity security) of the Company that (a) are offered and sold to Maxygen or its Affiliates, (b) are offered and sold to any Person other than Maxygen or its Affiliates, provided that Maxygen and its Affiliates hold a majority of the outstanding Units immediately following such offering and sale or (c) are junior to the Series B Preferred Units.

“Permitted Indebtedness” shall mean (a) accounts payable to trade creditors for goods and services and current operating liabilities (not the result of the borrowing of money) incurred in the ordinary course of the Company’s or such Subsidiary’s business in accordance with customary terms and paid within the specified time, unless contested in good faith by appropriate proceedings and reserved for in accordance with GAAP; (b) indebtedness consisting of guarantees resulting from endorsement of negotiable instruments for collection by the Company or any such Subsidiary in the ordinary course of business; (c) interest rate swaps, currency swaps and similar financial products entered into or obtained in the ordinary course of business; (d) capital leases or other indebtedness incurred solely to acquire and secure the purchase price of equipment, computers, software or implement tenant improvements and is not in excess of the lesser of the purchase price or the fair market value of such equipment, computers, software or tenant improvements on the date of acquisition; and (e) unsecured indebtedness of the Company to any of its wholly owned Subsidiaries or of any of its wholly owned Subsidiaries to another of its wholly owned Subsidiaries that is not senior to any indebtedness outstanding under the Bridge Loan Agreement.

“Person” shall mean any individual, corporation, association, partnership (general or limited), joint venture, trust, estate, limited liability company or other legal entity or organization.

“Profits Interest Unit” shall have the meaning set forth in Section 4.02(c).

“Profits and Losses” shall mean, for each Fiscal Year or other Fiscal Period, an amount equal to the Company’s taxable income or loss for such Fiscal Year or other Fiscal Period, as applicable, determined in accordance with Section 703(a) of the Code (but including in taxable income or loss, for this purpose, all items of income, gain, loss or deduction required to be stated separately pursuant to Section 703(a)(1) of the Code), with the following adjustments:

(a) any income of the Company exempt from U.S. federal income tax and not otherwise taken into account in computing Profits or Losses pursuant to this definition shall be added to such taxable income or loss;

(b) any expenditures of the Company described in Section 705(a)(2)(B) of the Code (or treated as expenditures described in Section 705(a)(2)(B) of the Code pursuant to Treasury Regulations Section 1.704-1(b)(2)(iv)(i)) and not otherwise taken into account in computing Profits or Losses pursuant to this definition shall be subtracted from such taxable income or loss;

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(c) in the event that the Gross Asset Value of any Company asset is adjusted in accordance with paragraphs (a) or (b) of the definition of “Gross Asset Value,” the amount of such adjustment shall be taken into account as gain or loss from the disposition of such asset for purposes of computing Profits or Losses;

(d) gain or loss resulting from any disposition of any asset of the Company with respect to which gain or loss is recognized for U.S. federal income tax purposes shall be computed by reference to the Gross Asset Value of the asset disposed of, notwithstanding that the adjusted tax basis of such asset differs from its Gross Asset Value;

(e) in lieu of the depreciation, amortization and other cost recovery deductions taken into account in computing such taxable income or loss, there shall be taken into account Depreciation for such Fiscal Year or other Fiscal Period, computed in accordance with the definition of “Depreciation” above; and

(f) to the extent an adjustment to the adjusted tax basis of any Company asset pursuant to Code Section 734(b) or Code Section 743(b) is required pursuant to Treasury Regulations Section 1.704 1(b)(2)(iv)(m)(4) to be taken into account in determining Capital Accounts as a result of a distribution other than in complete liquidation of a Member’s interest, the amount of such adjustment shall be treated as an item of gain (if the adjustment increases the basis of the asset) or loss (if the adjustment decreases the basis of the asset) from the disposition of the asset and shall be taken into account for purposes of computing Profits and Losses; and

(g) notwithstanding any other provision of this definition, any items which are specially allocated pursuant to Section 7.02(b) through Section 7.02(g) shall not be taken into account in computing Profits or Losses, but the amount thereof shall be determined under principles analogous to those set forth in clauses (a) through (f) of this definition.

“Proposed Treasury Regulation” shall have the meaning set forth in Section 4.02(d).

“Qualified Public Offering” shall have the meaning set forth in Section 4.03(b).

“Recapitalization” shall mean any Unit dividend, Unit split, combination of Units, reorganization, recapitalization, reclassification or other similar event.

“Related Entity” shall mean, with respect to any Member, (i) any corporation, trust, limited liability company, association or other entity in which such Member holds an 80% or greater equity interest, (ii) any parent corporation, trust, limited liability company or association, or other parent entity, of such Member or (iii) any liquidating trust or similar entity established for the benefit of such Member’s equityholders.

“Safe Harbor” shall have the meaning set forth in Section 4.02(d).

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“Sarbanes-Oxley Act” shall mean the Sarbanes-Oxley Act of 2002, as amended.

“Securities Act” shall mean the United States Securities Act of 1933, as amended.

“Subsidiary” shall have the meaning set forth in the Bridge Loan Agreement.

“Treasury Regulations” shall mean the regulations issued by the United States Treasury Department and relating to a matter arising under the Code.

“Unit” shall mean a unit of limited liability company interest in the Company and includes, without limitation, the Common Units and the Preferred Units.

“Updated Capital Account” shall mean, with respect to a Member, such Member’s Capital Account determined as if, immediately prior to the time of determination, all of the Company’s assets had been sold for fair market value and any previously unallocated Profits and Losses had been allocated pursuant to Article 7.

SECTION 1.02 Interpretation. Unless otherwise indicated herein, with respect to any reference made in this Agreement to a Section (or Article, Subsection, Paragraph, Subparagraph or Clause), Exhibit or Schedule, such reference shall be to a section (or article, subsection, paragraph, subparagraph or clause) of, or an exhibit or schedule to, this Agreement. The table of contents and any article, section, subsection, paragraph or subparagraph headings contained in this Agreement and the recitals at the beginning of this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed, as the context indicates, to be followed by the words “but (is/are) not limited to.” Words used herein, regardless of the number and gender specifically used, shall be deemed and construed to include any other number, singular or plural, and any other gender, masculine, feminine or neuter, as the context indicates is appropriate. Where specific language is used to clarify or illustrate by example a general statement contained herein, such specific language shall not be deemed to modify, limit or restrict the construction of the general statement which is being clarified or illustrated. Unless otherwise specified, any reference to a time or date shall be with reference to the time or date, as the case may be, in Wilmington, Delaware.

ARTICLE 2.

GENERAL MATTERS

SECTION 2.01 Formation.

(a) Pursuant to the provisions of the Delaware Act, the Company was formed on September 8, 2009, by the filing in the Office of the Secretary of State of the State of Delaware of a Certificate of Formation (which filing is hereby approved and ratified in all respects). The sole organizer of the Company is hereby designated as an “authorized person,” within the meaning of Section 18-201 of the Delaware Act, and all acts of such sole organizer in forming and organizing the Corporation are hereby approved, ratified, and adopted as valid and binding acts of the Company.

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(b) Each officer of the Company appointed by the Board of Managers pursuant to Section 5.04 is hereby designated as an “authorized person,” within the meaning of Section 18-201 of the Delaware Act, to execute, deliver and file, or cause the execution, delivery and filing of, all certificates, notices or other instruments (and any amendments and/or restatements thereof) required or permitted by the Delaware Act to be filed in the office of the Secretary of State of the State of Delaware and any other certificates, notices or other instruments (and any amendments or restatements thereof) necessary for the Company to qualify to do business in a jurisdiction in which the Company may wish to conduct business.

SECTION 2.02 Name. The name of the Company shall be “Perseid Therapeutics LLC”. Without the need to amend this Agreement, the Board of Managers may change the name of the Company from time to time in its sole discretion.

SECTION 2.03 Term. The term of the Company commenced with the filing of the Certificate of Formation in the office of the Secretary of State of the State of Delaware, and shall continue perpetually unless the Company is dissolved pursuant to Section 9.01.

SECTION 2.04 Registered Agent and Registered Office. The Company’s registered agent for service of process is The Corporation Trust Company, and the address of the registered agent and the address of the registered office of the Company in the State of Delaware shall be The Corporation Trust Company, Corporation Trust Center, 1209 Orange Street, Wilmington, DE 19801. Such registered agent and such registered office may be changed from time to time by the Board of Managers.

SECTION 2.05 Principal Place of Business. As of the date of this Agreement, the principal place of business of the Company is located in Redwood City, California. Thereafter, the principal place of business of the Company shall be in such location as the Board of Managers may designate from time to time.

SECTION 2.06 Purposes and Powers. The Company is formed for the object and purpose of, and the nature of the business to be conducted and promoted by the Company is, engaging in any act or activity for which limited liability companies may be formed under the Delaware Act. The Company shall have the power and authority to take any and all actions necessary, appropriate, proper, advisable, incidental or convenient to or for the furtherance of the purposes set forth in this Section 2.06.

SECTION 2.07 Books and Records. At all times during the continuance of the Company, the Company shall maintain or cause to be maintained proper and complete books and records in which shall be entered fully and accurately all transactions and other matters relating to the Company’s business in the detail and completeness customary and usual for businesses of the type engaged in by the Company.

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ARTICLE 3.

MEMBERS

SECTION 3.01 Members.

(a) Upon the execution of this Agreement, the sole Members of the Company shall be the Initial Members. Following the execution of this Agreement, no Person shall be admitted as a Member and no Units shall be issued by the Company except as expressly provided in this Agreement.

(b) After the date of this Agreement, a Person shall only be admitted as a Member (such Person, an “Additional Member”) if such Person is issued any Units in accordance with Section 4.02 or is a valid assignee or transferee of any then outstanding Units in accordance with the relevant provisions of the Investors’ Rights Agreement and the Co-Sale Agreement, as applicable. Nothing in this Agreement shall require the consent or approval of any Member for the admission of any Additional Member.

(c) The name and mailing address of each Member and the number of Units held by such Member shall be listed on Schedule A. An officer designated by the Board of Managers pursuant to Section 5.04 shall update Schedule A from time to time as necessary to accurately reflect changes in the Units of any Member to reflect the consummation of any action taken in accordance with this Agreement. Any amendment or revision to Schedule A made to reflect an action taken in accordance with this Agreement shall not be deemed an amendment to this Agreement. Any reference in this Agreement to Schedule A shall be deemed to be a reference to Schedule A as amended and in effect from time to time. The Company shall provide the Members with any amendment or revision of Schedule A (including any subsequent amendments or revisions thereto) within three (3) days of such amendment or revision.

SECTION 3.02 Powers of Members. Members shall not have the authority to transact any business in the Company’s name or bind the Company by virtue of their status as Members.

SECTION 3.03 Voting Rights.

(a) The Members hereby delegate the management of the Company to the Managers except with respect to (i) the automatic conversion of the Preferred Units in accordance with Section 4.03(b), (ii) the waiver of adjustments to the Conversion Price in accordance with Section 4.03(i), (iii) the shortening or waiver of certain notice provisions pursuant to Section 4.03(j), (iv) the designation and removal of Managers in accordance with Section 5.01(b), (v) the approval of those matters specified in Section 5.05 and Section 5.06, (vi) the approval of certain matters in connection with a Liquidity Event in accordance with Section 8.02, (vii) the dissolution of the Company in accordance with Section 9.01 and (viii) any amendment of this Agreement in accordance with Section 10.09.

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(b) Other than as provided herein, the Members shall vote together as a single class on all matters on which they are specifically entitled to vote pursuant to this Agreement. Each Member holding Preferred Units shall be entitled to the number of votes equal to the number of Common Units into which such Preferred Units could be converted as of the record date. Fractional votes shall not, however, be permitted and any fractional voting rights resulting from the above formula (after aggregating all Common Units into which Preferred Units held by each Member could be converted), shall be disregarded.

(c) Notwithstanding anything in this Agreement to the contrary, the Profits Interest Units shall be non-voting and shall not entitle the holders of Profits Interest Units, as such, to act for the Company or vote upon or approve any matter submitted to the Members for approval.

SECTION 3.04 Meetings and Written Consents of Members.

(a) The Company shall provide written notice to all Members of any meeting at which a vote will be held not less than ten (10) nor more than sixty (60) calendar days at prior thereto, which notice shall describe the business to be considered, the actions to be taken and the matters to be voted on at the meeting in reasonable detail. At any meeting of the Members, the presence, in person or by proxy, of Members holding a majority of the votes which could be cast by the holders of all Units entitled to vote at the meeting shall be necessary and sufficient to constitute a quorum, subject in each case to the provisions of Section 5.05 and Section 5.06. Any action permitted or required to be taken by the Members may be taken without a meeting, without prior notice and without a vote if a consent or consents in writing, setting forth the action so taken, shall be signed by the holders of Units having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all Units entitled to vote thereon were present and voted. Within five (5) calendar days of taking of action by Members without a meeting by less than unanimous written consent, the Company shall provide written notice of the taking of such action to those Members who have not consented in writing to the taking of such action, which notice shall describe the actions taken in reasonable detail.

(b) In order that the Company may determine the Members entitled to notice of or to vote at any meeting of Members or any adjournment thereof, or entitled to express consent to Company action in writing without a meeting, or entitled to receive payment of any dividend or other Distribution or allotment of any rights, or entitled to exercise any rights in respect of any change, conversion or exchange of Units or for the purpose of any other lawful action, the Board of Managers may fix a record date, which record date shall not precede the date upon which the resolution fixing the record date is adopted by the Board of Managers and which record date:

(i) in the case of determination of Members entitled to notice of or to vote at any meeting of Members or adjournment thereof, shall, unless otherwise required by law, not be more than sixty nor less than ten days before the date of such meeting;

(ii) in the case of determination of Members entitled to express consent to Company action in writing without a meeting, shall not be more than ten (10) days after the date upon which the resolution fixing the record date is adopted by the Board of Managers; and

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(iii) in the case of determination of Members for any other action, shall not be more than sixty (60) days prior to such other action.

If no record date is fixed by the Board:

(i) the record date for determining Members entitled to notice of or to vote at a meeting of Members shall be at the close of business on the day next preceding the day on which notice is given, or, if notice is waived, at the close of business on the day next preceding the day on which the meeting is held;

(ii) the record date for determining Members entitled to express consent to Company action in writing without a meeting when no prior action of the Board of Managers is required by law, shall be the first date on which a signed written consent setting forth the action taken or proposed to be taken is delivered to the Company in accordance with applicable law, or, if prior action by the Board of Managers is required by law, shall be at the close of business on the day on which the Board of Managers adopts the resolution taking such prior action; and

(iii) the record date for determining Members for any other purpose shall be at the close of business on the day on which the Board of Managers adopts the resolution relating thereto.

A determination of Members of record entitled to notice of or to vote at a meeting of Members shall apply to any adjournment of the meeting, provided that the Board of Managers may fix a new record date for the adjourned meeting.

(c) Each Member entitled to vote at a meeting of Members or to express consent or dissent to Company action in writing without a meeting may authorize another Person or Persons to act for such Member by proxy authorized by an instrument in writing or by a transmission permitted by law filed in accordance with the procedure established for the meeting, but no such proxy shall be voted or acted upon after three (3) years from its date, unless the proxy provides for a longer period.

SECTION 3.05 Liability of Members, Managers, Etc.

(a) Except to the extent provided in the Delaware Act, none of the Members or any Manager shall have any personal liability for the debts, obligations or liabilities of the Company.

(b) To the fullest extent permitted by applicable law (including Section 18-1101 of the Delaware Act), notwithstanding any other provision of this Agreement or otherwise of applicable law, including any in equity or at law, no Member, Manager, officer or employee of the Company (collectively, the “Covered Persons”), shall have any fiduciary duty to the Company, the Members or the Managers (or any other person or entity bound by this Agreement) by reason of this Agreement or the Company or in its capacity as a Covered Person, except that a Covered Person shall be subject to the implied contractual covenant of good faith and fair dealing and (to the extent expressly specified herein or therein) to the covenants and express obligations set forth in this

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Agreement and the Transaction Agreements. To the fullest extent permitted by applicable law (including Section 18-1101 of the Delaware Act), no Member or Manager shall be liable, including under any legal or equitable theory of fiduciary duty or other theory of liability, to the Company, any Member, any Manager or any other person or entity bound by this Agreement for any losses, claims, damages or liabilities incurred by reason of any act or omission performed or omitted by such Member or Manager in its capacity as a Member or Manager, except that (i) a Member or Manager shall be liable for any act or omission that constitutes a bad faith violation of the implied contractual covenant of good faith and fair dealing and (ii) a Member shall be liable for any breach by such Member of the covenants and express obligations set forth in this Agreement or the Transaction Agreements. The provisions of this Agreement, to the extent that they restrict or eliminate the duties and liabilities of a Member or Manager otherwise existing at law or in equity, are agreed by the parties hereto to replace such other duties and liabilities of such Member or Manager. Without limitation to the foregoing, the Company renounces any interest, right or expectancy of the Company in, or in being offered an opportunity to participate in, or in being informed about, any Excluded Opportunity. A Member or Manager shall be fully protected in relying in good faith upon the records of the Company and upon such information, opinions, reports or statements presented to the Company by any Person as to matters which such Member or Manager reasonably believes are within such Person’s professional or expert competence.

(c) (i) Each Person who was or is made a party or is threatened to be made a party to or is otherwise involved in any action, suit or proceeding, whether civil, criminal, administrative or investigative, by reason of the fact that he is or was a Manager or officer of the Company or is or was serving at the request of the Company as a Manager, officer, employee or agent of another limited liability company or of a corporation, partnership, joint venture, trust or other enterprise, including service with respect to an employee benefit plan (hereinafter an “Indemnitee”), whether the basis of such proceeding is alleged action in an official capacity as a Manager, officer, employee or agent or in any other capacity while serving as a Manager, officer, employee or agent, shall be indemnified and held harmless by the Company if the Indemnitee acted in good faith and in a manner the Indemnitee reasonably believed to be in or not opposed to the best interests of the Company, and, with respect to any criminal action or proceeding, had no reasonable cause to believe the Indemnitee’s conduct was unlawful, against all expense, liability and loss (including attorneys’ fees, judgments, fines, excise taxes under the Employee Retirement and Income Security Act of 1974 or penalties and amounts paid in settlement) reasonably incurred or suffered by such Indemnitee in connection therewith; provided, however, that except as provided in Section 3.05(f) with respect to proceedings to enforce rights to indemnification, the Company shall indemnify any such Indemnitee in connection with a proceeding (or part thereof) initiated by such Indemnitee only if such proceeding (or part thereof) was authorized by the Board of Managers. This Section 3.05(c)(i) shall not apply to any action by or in the right of the Company.

(ii) The Company shall indemnify any Indemnitee who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the Company to procure a judgment in its favor by reason of the fact that the Indemnitee is or was an Indemnitee, against expenses (including attorneys’ fees) actually and reasonably incurred by the Indemnitee in connection with the defense or settlement of such action or suit if the

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Indemnitee acted in good faith and in a manner the Indemnitee reasonably believed to be in or not opposed to the best interests of the Company, except that no indemnification shall be made in respect of any claim, issue or matter as to which the Indemnitee shall have been adjudged to be liable to the Company unless and only to the extent that the Delaware Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such Indemnitee is fairly and reasonably entitled to indemnity for such expenses which the Delaware Court of Chancery or such other court shall deem proper.

(d) To the extent that a present or former Manager or officer of the Company has been successful on the merits or otherwise in defense of any action, suit or proceeding described in Section 3.05(c), or in defense of any claim, issue or matter therein, such Indemnitee shall be indemnified against expenses (including attorneys’ fees) actually and reasonably incurred by such Indemnitee in connection therewith.

(e) The Company shall pay the expenses (including attorneys’ fees) incurred by a Manager in defending any Proceeding in advance of its final disposition; provided, however, that such payment of expenses incurred by an Indemnitee shall be made only upon receipt of an undertaking by such Manager to repay all amounts so advanced if it should be ultimately determined that such Indemnitee is not entitled to be indemnified under this Section 3.05(e) or otherwise. Such expenses (including attorneys’ fees) incurred by former Managers, officers or other employees and agents may be so paid upon such terms and conditions, if any, as the Company deems appropriate. The right to advancement of expenses shall not apply where indemnity is excluded pursuant to this Agreement. Notwithstanding the foregoing, unless otherwise determined pursuant to Section 3.05(j), no advance shall be made by the Company to an officer of the Company (except by reason of the fact that such officer is or was a Manager of the Company, in which event this sentence shall not apply) in any proceeding if a determination is reasonably and promptly made (i) by a majority vote of the Managers who are not parties to such proceeding, even though less than a quorum, or (ii) by a committee of such Managers designated by majority vote of such Managers, even though less than a quorum, or (iii) if there are no such Managers, or if such Managers so direct, by independent legal counsel in a written opinion, that facts known to the decision-making party at the time such determination is made demonstrate clearly and convincingly that such person acted in bad faith or in a manner that such person did not believe to be in or not opposed to the best interests of the Company.

(f) Subject to the requirements in this Section 3.05, the Company shall not be obligated to indemnify any person in connection with any proceeding (or any part of any proceeding):

(i) for which payment has actually been made to or on behalf of such person under any statute, insurance policy, indemnity provision, vote or otherwise, except with respect to any excess beyond the amount paid;

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(ii) for an accounting or disgorgement of profits pursuant to Section 16(b) of the Exchange Act, or similar provisions of federal, state or local statutory law or common law, if such person is held liable therefor (including pursuant to any settlement arrangements);

(iii) for any reimbursement of the Company by such person of any bonus or other incentive-based or equity-based compensation or of any profits realized by such person from the sale of securities of the Company, as required in each case under the Exchange Act, as amended (including any such reimbursements that arise from an accounting restatement of the Company pursuant to Section 304 of the Sarbanes-Oxley Act, or the payment to the Company of profits arising from the purchase and sale by such person of securities in violation of Section 306 of the Sarbanes-Oxley Act), if such person is held liable therefor (including pursuant to any settlement arrangements);

(iv) initiated by such person, including any proceeding (or any part of any proceeding) initiated by such person against the Company or its directors, officers, employees, agents or other indemnitees, unless (a) the Board authorized the Proceeding (or the relevant part of the Proceeding) prior to its initiation, (b) the Company provides the indemnification, in its sole discretion, pursuant to the powers vested in the Company under applicable law, (c) otherwise required to be made under SECTION 3.05(g) or otherwise required by applicable law; or

(v) if prohibited by applicable law.

(g) If a claim under Section 3.05(c) or Section 3.05(d) is not paid in full by the Company within ninety (90) calendar days after a written claim has been received by the Company, the Indemnitee may at any time thereafter bring suit against the Company to recover the unpaid amount of the claim. If successful in whole or in part in any such suit, or in a suit brought by the Company to recover an advancement of expenses pursuant to the terms of an undertaking, the Indemnitee shall also be entitled to be paid the expenses of prosecuting or defending such suit. In (i) any suit brought by the Indemnitee to enforce a right to indemnification hereunder (but not in a suit brought by the Indemnitee to enforce a right to an advancement of expenses) it shall be a defense that, and (ii) any suit brought by the Company to recover an advancement of expenses pursuant to the terms of an undertaking, the Company shall be entitled to recover such expenses upon a final adjudication that, the Indemnitee has not met the applicable standard for indemnification set forth in Section 3.05(c) and Section 3.05(d). Neither the failure of the Company (including its Board of Managers, independent legal counsel, or its Members) to have made a determination prior to the commencement of such suit that indemnification of the Indemnitee is proper in the circumstances because the Indemnitee has met the standard of conduct for entitlement to indemnification, nor an actual determination by the Company (including its Board of Managers, independent legal counsel, or its Members) that the Indemnitee has not met the standard of conduct for entitlement to indemnification, shall create a presumption that the Indemnitee has not met such standard of conduct or, in the case of such a suit brought by the Indemnitee, be a defense to such suit. In any suit brought by the Indemnitee to enforce a right to indemnification or to an advancement of expenses hereunder, or brought by the Company to recover an advancement of expenses pursuant to the terms of an undertaking, the burden of proving that the Indemnitee is not

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entitled to be indemnified, or to such advancement of expenses, under this Section 3.05 or otherwise shall be on the Company. The termination of a proceeding by judgment, order, settlement, conviction, or upon a plea of nolo contendere or its equivalent shall not of itself create a presumption that a Manager or officer acted in such a manner as to make him or her ineligible for indemnification.

(h) The rights to indemnification and to the advancement of expenses conferred in this Section 3.05 shall not be exclusive of any other right which any Person may have or hereafter acquire under any statute, this Agreement, any other agreement, any vote of Managers or otherwise.

(i) The Company may maintain insurance, at its expense, to protect itself and any Member, Manager, officer, employee or agent of the Company or another limited liability company, corporation, partnership, joint venture, trust or other enterprise against any expense, liability or loss, whether or not the Company would have the power to indemnify such Person against such expense, liability or loss under the Delaware Act.

(j) The Company may, to the extent authorized from time to time by the Board of Managers, grant rights to indemnification and to the advancement of expenses to any person or entity not mandatorily entitled to indemnification under this Section 3.05 and grant rights to indemnification and to the advancement of expenses in addition to those granted in this Section 3.05 to any person or entity mandatorily entitled to indemnification under this Section 3.05, in each case as long as such person or entity has met the standard of conduct set forth in the first sentence of Section 3.05(b).

(k) The rights to indemnification and advancement of expenses conferred by this Section 3.05 shall continue as to a person who has ceased to be a Manager, officer, employee or agent and shall inure to the benefit of the heirs, executors and administrators of such a person. Any amendment, alteration or repeal of this Section 3.05 shall not adversely affect any right or protection hereunder of any person in respect of any act or omission occurring prior to such amendment, alteration or repeal.

SECTION 3.06 Resignation. Other than by transferring all of its Units, a Member may not resign from the Company.

ARTICLE 4.

NEW ISSUANCES; UNITS; CONVERSION

SECTION 4.01 New Issuances of Equity Capital. Subject to the terms of this Agreement (including Section 5.05 and Section 5.06), the Board of Managers may determine the form, timing and terms of any new issuance of equity capital (including Units) of the Company to any Person and, other than with respect to issuances of Common Units to eligible Persons pursuant to the terms of the Equity Incentive Plan, will notify the Members of such decision. Any such Person shall be required to become a party to this Agreement as a Member, and shall have all the rights and obligations of a Member hereunder, by executing an Adoption Agreement in form satisfactory to the Board of Managers.

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SECTION 4.02 Units.

(a) Interests in the Company are represented by one or more classes of Units. The Units shall for all purposes be personal property in accordance with Section 18-701 of the Delaware Act. No holder of a Unit or Member shall have any interest in specific Company assets, including any assets contributed to the Company by such Member as part of any capital contribution. Each Member waives any and all rights that it may have to maintain an action for partition of the Company’s property.

(b) The Units initially will be divided into Preferred Units and Common Units. The first series of Preferred Units will be designated as Series A Preferred Units and the second series of Preferred Units will be designated as Series B Preferred Units. Each Unit shall have the rights and privileges set forth in this Agreement.

(c) Subject to Section 5.05 and Section 5.06, upon the issuance of any Common Units to Managers, officers, employees or other service providers, the Board of Managers may specify a “Distribution Threshold,” if any, applicable to such Common Units, which shall be equal to the minimum amount determined by the Board of Managers in its reasonable discretion to be necessary to cause such Common Unit to constitute a “profits interest” for U.S. federal income tax purposes (a “Profits Interest Unit”) or such greater amount as the Board of Managers, in its reasonable discretion, may determine. All vested Profits Interest Units shall terminate no later than the Option Closing (as such term is defined in the Investors’ Rights Agreement), with the unvested Profits Interest Units to terminate subsequently in accordance with the Equity Incentive Plan, and in each case all such terminated Profits Interest Units shall be exchanged for a cash payment as provided for under the Investors’ Rights Agreement and the Equity Incentive Plan. Immediately upon receipt of a Profits Interest Unit, the recipient will have no initial Capital Account balance and the Profits Interest Unit received shall not entitle such Person to any portion of the capital of the Company at the time of such Person’s admission to the Company as a Member, such that if the Company’s assets were sold at fair market value immediately after the grant to such Member of a Profits Interest Unit and the proceeds distributed in complete liquidation of the Company, the Profits Interest Unit so received would entitle such Member to receive no share of those proceeds. The grant of a Profits Interest Unit to a Member is intended to comply with Rev. Proc. 93-27, 1993-2 C.B. 343 (1993) and Rev. Proc. 2001-43, 2001-2 C.B. 191 (2001) and shall be interpreted consistently therewith.

(d) Each Member authorizes the Managing Member to elect to apply the safe harbor (the “Safe Harbor”) set forth in proposed Treasury Regulation Section 1.83-3(l) and proposed IRS Revenue Procedure published in Notice 2005-43 (together, the “Proposed Treasury Regulation”) (under which the fair market value of an interest in an entity taxable as a partnership that is transferred in connection with the performance of services is treated as being equal to the liquidation value of the interest) if such Proposed Treasury Regulation or a similar Treasury Regulation is promulgated as a final or temporary Treasury Regulation. If the Managing Member determines that

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the Company should make such election, the Managing Member is hereby authorized to amend this Agreement without the consent of any Member or other Person to provide that (i) the Company is authorized and directed to elect the Safe Harbor, (ii) the Company and each Member (including any Person to whom an Unit is transferred in connection with the performance of services) will comply with all requirements of the Safe Harbor with respect to all Units transferred in connection with the performance of services while such election remains in effect and (iii) the Company and each Member will take all actions necessary, including providing the Company with any required information, to permit the Company to comply with the requirements set forth or referred to in the applicable Treasury Regulations for such election to be effective such time (if any) as the Managing Member determines, in his sole discretion, that the Company should terminate such election. Notwithstanding anything to the contrary in this Agreement, each Member expressly confirms and agrees that it will be legally bound by any such amendment. Notwithstanding the preceding sentences, no election or amendment shall be made pursuant to this Section 4.02(d) if the Safe Harbor, when finalized, is substantially different from the one included in the Proposed Treasury Regulation, unless the Managing Member has determined that the application of the Safe Harbor would not result in materially adverse tax consequences to the Members.

(e) All Units other than the Profits Interest Units shall be evidenced by certificates in accordance with Section 18-702 of the Delaware Act, in form approved by the Board of Managers.

(f) Except as provided in this Section 4.02(f), no new certificates for Units shall be issued to replace a previously issued certificate unless the latter is surrendered to the Company and cancelled at the same time. The Company may issue a new certificate of Units or uncertificated shares in the place of any certificate theretofore issued by it, alleged to have been lost, stolen or destroyed, and the Company may require the owner of the lost, stolen or destroyed Unit, or such owner’s legal representative, to give the Company a bond sufficient to indemnify it against any claim that may be made against it on account of the alleged loss, theft or destruction of any such certificate or the issuance of such new certificate or uncertificated Units.

(g) Subject to the restrictions on transfer set forth in the Investors’ Rights Agreement, transfers of record of Units shall be made only upon its books by the holders thereof, in person or by an attorney duly authorized, and, if such stock is certificated, upon the surrender of a certificate or certificates for a like number of Units, properly endorsed or accompanied by proper evidence of succession, assignation or authority to transfer.

SECTION 4.03 Conversion. The holders of the Preferred Units shall have conversion rights as follows:

(a) Right to Convert. Each Preferred Unit shall be convertible, at the option of the Member holding such Preferred Unit and at any time after the date of issuance of such Preferred Unit at the office of the Company or any transfer agent for the Preferred Units, into that number of Common Units determined by dividing the Original Issue Price for the relevant series of Preferred Units by the Conversion Price for such series. The rate at which each series of Preferred Units may be converted into Common Units is hereinafter referred to as the “Conversion Rate” for each such

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series. Upon any decrease or increase in the Conversion Price for any series of Preferred Units, as described in this Section 4.03, the Conversion Rate for such series shall be appropriately increased or decreased. In the event of a liquidation, dissolution or winding up of the Company, the option of the Member holding Preferred Units to convert such Preferred Units into Common Units pursuant to this Section 4.03(a) shall terminate at the close of business on the last full day preceding the date fixed for the payment of any such amounts distributable on such event to the Members holding Preferred Units.

(b) Automatic Conversion. Each Preferred Unit as specified hereafter shall automatically be converted into Common Units at the then effective Conversion Rate for such share (i) with respect to Preferred Units, immediately prior to the closing of a firm commitment underwritten initial public offering pursuant to an effective registration statement filed under the Securities Act covering the offer and sale of the Common Units of the Company (following conversion of the Company to a corporation pursuant to the terms of Section 9.04), provided that the pre-offering valuation is at least $200,000,000 and the aggregate gross proceeds to the Company are more than $50,000,000 (a “Qualified Public Offering”), (ii) with respect to Series A Preferred Units only, upon the receipt by the Company of a written request for such conversion from the Members holding a majority of the Series A Preferred Units then outstanding (voting as a separate class), or (iii) with respect to Series B Preferred Units only, upon the receipt by the Company of a written request for such conversion from the Members holding a majority of the Series B Preferred Units then outstanding (voting as a separate class), or, if later, the effective date for conversion specified in such requests (each of the events referred to in (i), (ii) and (iii) is referred to herein as an “Automatic Conversion Event”).

(c) Mechanics of Conversion. No fractional Common Units shall be issued upon conversion of Preferred Units. In lieu of any fractional Common Units to which the holder would otherwise be entitled, the Company shall pay cash equal to such fraction multiplied by the then fair market value of a Common Unit as determined by the Board of Managers. For such purpose, all Preferred Units held by each Member holding Preferred Units shall be aggregated, and any resulting fractional Common Units shall be paid in cash. Before any Member holding Preferred Units shall be entitled to convert the same into full Common Units, and to receive certificates therefor, he shall either (A) surrender the certificate or certificates therefor, duly endorsed, at the office of the Company or of any transfer agent for the Preferred Units or (B) notify the Company or its transfer agent that such certificates have been lost, stolen or destroyed and execute an agreement satisfactory to the Company to indemnify the Company from any loss incurred by it in connection with such certificates, and shall give written notice to the Company at such office that he elects to convert the same; provided, however, that on the date of an Automatic Conversion Event, the outstanding Preferred Units or series thereof, as applicable, shall be converted automatically without any further action by the holders of such Preferred Units and whether or not the certificates representing such Preferred Units are surrendered to the Company or its transfer agent; provided further, however, that the Company shall not be obligated to issue certificates evidencing the Common Units issuable upon such Automatic Conversion Event unless either the certificates evidencing such Preferred Units or series thereof, as applicable, are delivered to the Company or its transfer agent as provided above, or the Member holding such Preferred Units notifies the Company or its transfer agent that such

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certificates have been lost, stolen or destroyed and executes an agreement satisfactory to the Company to indemnify the Company from any loss incurred by it in connection with such certificates. On the date of the occurrence of an Automatic Conversion Event, each holder of record of Preferred Units shall be deemed to be the holder of record of the Common Units issuable upon such conversion, notwithstanding that the certificates representing such Preferred Units shall not have been surrendered at the office of the Company, that notice from the Company shall not have been received by any holder of record of Preferred Units, or that the certificates evidencing such Common Units shall not then be actually delivered to such holder.

The Company shall, as soon as practicable after such delivery, or after such agreement and indemnification, issue and deliver at such office to such Member holding Preferred Units, a certificate or certificates for the number of Common Units to which such Member shall be entitled as aforesaid and a check payable to the Member in the amount of any cash amounts payable as the result of a conversion into fractional Common Units, plus any declared and unpaid Distributions on the converted Preferred Stock. Such conversion shall be deemed to have been made immediately prior to the close of business on the date of such surrender of the Preferred Units to be converted, and the person or persons entitled to receive the Common Units issuable upon such conversion shall be treated for all purposes as the record holder or holders of such Common Units on such date; provided, however, that if the conversion is in connection with an underwritten offer of securities registered pursuant to the Securities Act or a merger, sale, financing, or liquidation of the Company or other event, the conversion may, at the option of any Member tendering Preferred Units for conversion, be conditioned upon the closing of such transaction or upon the occurrence of such event, in which case the person(s) entitled to receive the Common Units issuable upon such conversion of the Preferred Units shall not be deemed to have converted such Preferred Units until immediately prior to the closing of such transaction or the occurrence of such event.

(d) Adjustments to Conversion Price for Diluting Issues.

(i) Special Definition. For purposes of this Section 4.03(d), “Additional Common Units” shall mean all Common Units issued (or, pursuant to Section 4.03(d)(iii), deemed to be issued) by the Company after the date of this Agreement, other than issuances or deemed issuances of:

(1) Common Units upon the conversion of the Preferred Units;

(2) Common Units (including Profits Interest Units) and Options issued or issuable to Managers, officers, employees, consultants, placement agents or other service providers of the Company (or any Subsidiary) pursuant to Unit grants, profit interest plans, restricted unit purchase agreements, option plans, purchase plans, agreements or other employee equity incentive programs or similar arrangements approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Manager chosen by Bio (a “Bio Manager”) and at least one Manager chosen by Maxygen (a “Maxygen Manager”), in each case pursuant to the Voting Agreement, if applicable; provided that the approval of at least one Bio Manager and one Maxygen Manager (if applicable) shall only be required with respect to the issuance of greater than

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an aggregate of 15,000,000 Common Units (including Profits Interest Units and the number of Common Units for or into which all Options and Convertible Securities are exercisable or convertible);

(3) Common Units issued or issuable pursuant to the acquisition of another company by the Company by merger, purchase of substantially all of the assets or other reorganization or to a joint venture agreement, provided, that such issuances are approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Bio Manager and one Maxygen Manager;

(4) Common Units issued or issuable to banks, equipment lessors or other financial institutions pursuant to a debt financing or commercial leasing transaction approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Bio Manager and one Maxygen Manager;

(5) Common Units issued or issuable in connection with any settlement of any action, suit, proceeding or litigation approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Bio Manager and one Maxygen Manager;

(6) Common Units issued or issuable in connection with sponsored research, collaboration, technology license, development, OEM, marketing or other similar agreements or strategic partnerships approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Bio Manager and one Maxygen Manager;

(7) Common Units issued or issuable to suppliers or third party service providers in connection with the provision of goods or services pursuant to transactions approved by the Board of Managers, which, prior to the later of the termination of the Buy-Out Option and such time as no amounts are outstanding under the Bridge Loan Agreement, shall include at least one Bio Manager and one Maxygen Manager;

(8) Common Units actually issued upon the exercise or conversion of Options or Convertible Securities, in each case provided such issuance is pursuant to the terms of such Option or Convertible Security;

(9) Common Units issued or issuable as a dividend or distribution on Preferred Units or pursuant to any event for which adjustment is made pursuant to Sections 4.03(e), 4.03(f) or 4.03(g) hereof;

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(10) any security that the Members holding the majority of Series A Preferred Units, voting as a separate class, and Members holding the majority of Series B Preferred Units, voting as a separate class, designate as not constituting Additional Common Units; and

(11) following conversion of the Company to a corporation pursuant to the terms of Section 9.04, Common Units of the Company issued or issuable in a registered public offering under the Securities Act.

(ii) No Adjustment of Conversion Price. No adjustment in the Conversion Price of a particular series of Preferred Units shall be made in respect of the issuance of Additional Common Units unless the consideration per Preferred Unit (as determined pursuant to Section 4.03(d)(v)) for an Additional Common Unit issued or deemed to be issued by the Company is less than the Conversion Price in effect on the date of, and immediately prior to such issue, for such series of Preferred Units.

(iii) Deemed Issue of Additional Common Units. In the event the Company at any time or from time to time after the date of the date of this Agreement shall issue any Options or Convertible Securities or shall fix a record date for the determination of holders of any class of securities entitled to receive any such Options or Convertible Securities, then the maximum number of Common Units (as set forth in the instrument relating thereto without regard to any provisions contained therein for a subsequent adjustment of such number) issuable upon the exercise of such Options or, in the case of Convertible Securities, the conversion or exchange of such Convertible Securities or, in the case of Options for Convertible Securities, the exercise of such Options and the conversion or exchange of the underlying securities, shall be deemed to have been issued as of the time of such issue or, in case such a record date shall have been fixed, as of the close of business on such record date, provided that in any such case in which Units are deemed to be issued:

(1) no further adjustment in the Conversion Price of any series of Preferred Units shall be made upon the subsequent issue of Convertible Securities or Common Units in connection with the exercise of such Options or conversion or exchange of such Convertible Securities;

(2) if such Options or Convertible Securities by their terms provide, with the passage of time or otherwise, for any change in the consideration payable to the Company or in the number of Common Units issuable upon the exercise, conversion or exchange thereof (other than a change pursuant to the anti-dilution provisions of such Options or Convertible Securities such as this Section 4.03(d) or pursuant to Recapitalization provisions of such Options or Convertible Securities such as Section 4.03(e), Section 4.03(f) and Section 4.03(g) hereof), the Conversion Price of each series of Preferred Units and any subsequent adjustments based thereon shall be recomputed to reflect such change as if such change had been in effect as of the original issue thereof (or upon the occurrence of the record date with respect thereto);

(3) no readjustment pursuant to clause (2) above shall have the effect of increasing the Conversion Price of a series of Preferred Units to an amount above the

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Conversion Price that would have resulted from any other issuances of Additional Common Units and any other adjustments provided for herein between the original adjustment date and such readjustment date;

(4) upon the expiration of any such Options or any rights of conversion or exchange under such Convertible Securities which shall not have been exercised, the Conversion Price of each series of Preferred Units computed upon the original issue thereof (or upon the occurrence of a record date with respect thereto) and any subsequent adjustments based thereon shall, upon such expiration, be recomputed as if:

a) in the case of Convertible Securities or Options for Common Units, the only Additional Common Units issued were the Common Units, if any, actually issued upon the exercise of such Options or the conversion or exchange of such Convertible Securities and the consideration received therefor was the consideration actually received by the Company for the issue of such exercised Options plus the consideration actually received by the Company upon such exercise or for the issue of all such Convertible Securities which were actually converted or exchanged, plus the additional consideration, if any, actually received by the Company upon such conversion or exchange, and

b) in the case of Options for Convertible Securities, only the Convertible Securities, if any, actually issued upon the exercise thereof were issued at the time of issue of such Options, and the consideration received by the Company for the Additional Common Units deemed to have been then issued was the consideration actually received by the Company for the issue of such exercised Options, plus the consideration deemed to have been received by the Company (determined pursuant to Section 4.03(d)(v)) upon the issue of the Convertible Securities with respect to which such Options were actually exercised; and

(5) if such record date shall have been fixed and such Options or Convertible Securities are not issued on the date fixed therefor, the adjustment previously made in the Conversion Price which became effective on such record date shall be canceled as of the close of business on such record date, and thereafter the Conversion Price shall be adjusted pursuant to this Section 4.03(d)(iii) as of the actual date of their issuance.

(iv) Adjustment of Conversion Price Upon Issuance of Additional Common Units. In the event this Company shall issue Additional Common Units (including Additional Common Units deemed to be issued pursuant to Section 4.03(d)(iii)) without consideration or for a consideration per Unit less than the applicable Conversion Price of a series of Preferred Units in effect on the date of and immediately prior to such issue, then, the Conversion Price of the affected series of Preferred Units shall be reduced, concurrently with such issue, to a price (calculated to the nearest cent) determined by multiplying such Conversion Price by a fraction, the numerator of which shall be the number of Common Units outstanding immediately prior to such issue plus the number of Common Units which the aggregate consideration received by the Company for the total number of Additional Common Units so issued would purchase at such Conversion Price, and the denominator of which shall be the number of Common Units outstanding immediately prior to such issue plus the number of such Additional Common Units so issued.

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Notwithstanding the foregoing, the Conversion Price shall not be reduced at such time if the amount of such reduction would be less than $0.01, but any such amount shall be carried forward, and a reduction will be made with respect to such amount at the time of, and together with, any subsequent reduction which, together with such amount and any other amounts so carried forward, equal $0.01 or more in the aggregate. For the purposes of this Section 4.03(d)(iv), all Common Units issuable upon conversion of all outstanding Preferred Units and the exercise and/or conversion of any other outstanding Convertible Securities and all outstanding Options shall be deemed to be outstanding.

(v) Determination of Consideration. For purposes of this Section 4.03(d) , the consideration received by the Company for the issue (or deemed issue) of any Additional Common Units shall be computed as follows:

(1) Cash and Property. Such consideration shall:

a) insofar as it consists of cash, be computed at the aggregate amount of cash received by the Company before deducting any reasonable discounts, commissions or other expenses allowed, paid or incurred by the Company for any underwriting or otherwise in connection with such issuance;

b) insofar as it consists of property other than cash, be computed at the fair market value thereof at the time of such issue, as determined in good faith by the Board of Managers; and

c) in the event Additional Common Units are issued together with other Units or securities or other assets of the Company for consideration which covers both, be the proportion of such consideration so received, computed as provided in clauses (a) and (b) above, as reasonably determined in good faith by the Board of Managers.

(2) Options and Convertible Securities. The consideration per Unit received by the Company for Additional Common Units deemed to have been issued pursuant to Section 4.03(d)(iii) shall be determined by dividing:

(x) the total amount, if any, received or receivable by the Company as consideration for the issue of such Options or Convertible Securities, plus the minimum aggregate amount of additional consideration (as set forth in the instruments relating thereto, without regard to any provision contained therein for a subsequent adjustment of such consideration) payable to the Company upon the exercise of such Options or the conversion or exchange of such Convertible Securities, or in the case of Options for Convertible Securities, the exercise of such Options for Convertible Securities and the conversion or exchange of such Convertible Securities by

(y) the maximum number of Common Units (as set forth in the instruments relating thereto, without regard to any provision contained therein for a subsequent adjustment of such number) issuable upon the exercise of such Options or the conversion or exchange of such Convertible Securities.

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(e) Adjustments for Subdivisions or Combinations of Common Units. In the event the outstanding Common Units shall be subdivided (by stock split, by payment of a stock dividend or otherwise), into a greater number of Common Units, the Conversion Price of each series of Preferred Units in effect immediately prior to such subdivision shall, concurrently with the effectiveness of such subdivision, be proportionately decreased. In the event the outstanding Common Units shall be combined (by reclassification or otherwise) into a lesser number of Common Units, the Conversion Prices in effect immediately prior to such combination shall, concurrently with the effectiveness of such combination, be proportionately increased.

(f) Adjustments for Subdivisions or Combinations of Preferred Units. In the event the outstanding Preferred Units or a series of Preferred Units shall be subdivided (by stock split, by payment of a stock dividend or otherwise), into a greater number of Preferred Units, the Annual Distribution Rate, Original Issue Price and Liquidation Preference of the affected series of Preferred Units in effect immediately prior to such subdivision shall, concurrently with the effectiveness of such subdivision, be proportionately decreased. In the event the outstanding Preferred Units or a series of Preferred Units shall be combined (by reclassification or otherwise) into a lesser number of Preferred Units, the Annual Distribution Rate, Original Issue Price and Liquidation Preference of the affected series of Preferred Units in effect immediately prior to such combination shall, concurrently with the effectiveness of such combination, be proportionately increased.

(g) Adjustments for Reclassification, Exchange and Substitution. Subject to Section 8.02 (“Liquidation Rights”), if the Common Units issuable upon conversion of the Preferred Units shall be changed into the same or a different number of Units of any other class or classes of Units, whether by capital reorganization, reclassification or otherwise (other than a subdivision or combination of Units provided for above), then, in any such event, in lieu of the number of Common Units which the holders would otherwise have been entitled to receive, each holder of such Preferred Units shall have the right thereafter to convert such Preferred Units into a number of such other class or classes of Units which a holder of the number of Common Units deliverable upon conversion of such series of Preferred Units immediately before that change would have been entitled to receive in such reorganization or reclassification, all subject to further adjustment as provided herein with respect to such other Units.

(h) Certificate as to Adjustments. Upon the occurrence of each adjustment or readjustment of the Conversion Price pursuant to this Section 4.03, the Company at its expense shall promptly compute such adjustment or readjustment in accordance with the terms hereof and furnish to each holder of Preferred Units a certificate setting forth such adjustment or readjustment and showing in detail the facts upon which such adjustment or readjustment is based. The Company shall, upon the written request at any time of any holder of Preferred Units, furnish or cause to be furnished to such holder a like certificate setting forth (i) such adjustments and readjustments, (ii) the Conversion Price at the time in effect and (iii) the number of Common Units and the amount, if any, of other property which at the time would be received upon the conversion of Preferred Units.

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(i) Waiver of Adjustment of Conversion Price. Notwithstanding anything herein to the contrary, any downward adjustment of the Conversion Price of any series of Preferred Units may be waived by the consent or vote of the holders of the majority of the outstanding Preferred Units of such series either before or after the issuance causing the adjustment. Any such waiver shall bind all future holders of such series of Preferred Units.

(j) Notices of Record Date. In the event that this Company shall propose at any time:

(i) to declare any Distribution upon its Common Units, whether in cash, property, stock or other securities, whether or not a regular cash dividend and whether or not out of earnings or earned surplus;

(ii) to effect any reclassification or recapitalization of its Common Units outstanding involving a change in the Common Units; or

(iii) to voluntarily liquidate or dissolve or to enter into any transaction or series of related transactions deemed to be a Liquidity Event;

then, in connection with each such event, this Company shall send to the holders of the Preferred Units at least twenty (20) days’ prior written notice of the date on which a record shall be taken for such Distribution (and specifying the date on which the holders of Common Units shall be entitled thereto and, if applicable, the amount and character of such Distribution) or for determining rights to vote in respect of the matters referred to in (ii) and (iii) above.

Such written notice shall be given by first class mail (or express courier), postage prepaid, addressed to the holders of Preferred Units at the address for each such holder as shown on the books of the Company and shall be deemed given on the date such notice is mailed.

The notice provisions set forth in this section may be shortened or waived prospectively or retrospectively by the consent or vote of the holders of a majority of Series A Preferred Units, voting as a separate class, and of a majority of Series B Preferred Units, voting as a separate class.

ARTICLE 5.

GOVERNANCE

SECTION 5.01 Board of Managers.

(a) The Company shall have a board of managers (the “Board of Managers”). The Members hereby designate the Board of Managers as the managers (within the meaning of the Delaware Act) of the Company, with exclusive rights and responsibilities to direct the business of the Company. The Board of Managers shall have the power to do any and all acts necessary or convenient to or for the furtherance of the purposes described herein, including all powers, statutory or otherwise, possessed by managers under the laws of the State of Delaware. Without limitation to the foregoing, the Board of Managers shall have the authority to fix the compensation of Managers.

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(b) The Board of Managers shall consist of five (5) members (each, a “Manager”). The initial Managers shall be elected by the Initial Members. So long as at least six million (6,000,000) Preferred Units (as adjusted for Recapitalizations) remain outstanding, the holders of Preferred Units, voting as a separate class, shall be entitled to elect five (5) members of the Board of Managers at each meeting or pursuant to each consent of the Members (the “Preferred Managers”). Any members of the Board of Managers not elected pursuant to the immediately preceding sentence shall be elected by the holders of Common Units and Preferred Units, voting together as a single class. A Manager may be removed by the holders of a majority of the Units then entitled to vote at an election of Managers that are then entitled to elect such Manager; provided, however, that notwithstanding the foregoing, a Preferred Manager shall be removed in accordance with the terms of the Voting Agreement. If a vacancy on the Board of Managers is to be filled by the Board of Managers, only Managers elected by the same class or classes of Members as those who would be entitled to vote to fill such vacancy shall vote to fill such vacancy; provided, however, that notwithstanding the foregoing, a Preferred Manager vacancy shall be filled in accordance with the terms of the Voting Agreement. A Manager shall hold office until his or her successor is designated or until his or her earlier death, resignation or removal.

SECTION 5.02 Meetings and Written Consents of Board of Managers.

(a) Any Manager may attend a meeting of the Board of Managers in person, by telephone or any other electronic communication device. At any meeting of the Board of Managers, the presence, in person or by proxy, of a majority of the Managers shall constitute a quorum. A Manager entitled to vote at any meeting of the Board of Managers may authorize another Person, including another Manager, to act in place of that Manager by proxy. The Board of Managers may act by unanimous written consent in lieu of a meeting in accordance with Section 18-404 of the Delaware Act.

(b) At any meeting of the Board of Managers, any action taken by the Board of Managers shall require the approval of a majority of the Managers present, in person or by proxy, at such meeting. Each Manager shall be entitled to one vote.

SECTION 5.03 Committees. The Board of Managers may designate by unanimous action, one or more committees, each committee to consist of one or more of the Managers of the Company. The Board of Managers may designate one or more Managers as alternate members of any committee, who may replace any absent or disqualified member at any meeting of the committee. In the absence or disqualification of a member of a committee, the member or members thereof present at any meeting and not disqualified from voting, whether or not such member or members constitute a quorum, may unanimously appoint another member of the Board of Managers to act at the meeting in the place of any such absent or disqualified member. Any such committee, to the extent provided in the resolution of the Board of Managers or in this Agreement, shall have and may exercise all the powers and authority of the Board of Managers in the management of the business and affairs of the Company; provided, however, that no such committee shall have the power or authority in reference to the following matters: (i) approving or adopting, or recommending to the Members, any action or matter expressly required by this Agreement to be submitted to Members for approval or (ii) adopting, amending or repealing this Agreement. To the extent that any committee does not include the Minority Preferred Designee (as defined in the Voting Agreement), then the Minority Preferred Designee shall be entitled to attend in a non-voting, observer capacity all meetings of such committee and to receive all notices and other communications (including, without limitation,

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Actions by Written Consent Without a Meeting) that are sent to members of such committee in their capacity as such. Meetings and actions of committees shall be governed by, and held and taken in accordance with, Section 5.02.

SECTION 5.04 Officers.

(a) The Board of Managers may from time to time appoint (and subsequently remove) individuals to act on behalf of the Company as “officers” or “agents” of the Company within the meaning of Section 18-407 of the Delaware Act to conduct the day-to-day management of the Company with such general or specific authority as the Board of Managers may specify. Such officers may include a Chief Executive Officer, a President, one or more Vice Presidents, a Chief Financial Officer, a Treasurer, one or more Assistant Treasurers, a Secretary and one or more Assistant Secretaries. Any number of offices may be held by the same person.

(b) The Board of Managers may appoint, or empower the Chief Executive Officer or, in the absence of a Chief Executive Officer, the President, to appoint, such other officers and agents as the business of the Company may require. Each of such officers and agents shall hold office for such period, have such authority, and perform such duties as are provided in this Agreement or as the Board of Managers may from time to time determine.

(c) Unless otherwise directed by the Board of Managers, the Chief Executive Officer or President or any other person authorized by the Board of Managers, the Chief Executive Officer or the President is authorized to vote, represent and exercise on behalf of the Company all rights incident to any and all shares of any other corporation or corporations standing in the name of the Company. The authority granted herein may be exercised either by such person directly or by any other person authorized to do so by proxy or power of attorney duly executed by such person having the authority.

(d) Except as otherwise provided in this Agreement, the officers of the Company shall have such powers and duties in the management of the Company as may be designated from time to time by the Board of Managers and, to the extent not so provided, as generally pertain to their respective offices in the context of a Delaware corporation, subject to the control of the Board of Managers.

SECTION 5.05 Series A Preferred Unit Protective Provisions.

(a) Prior to the Option Expiration Date and as long as at least twenty five million (25,000,000) Series A Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the outstanding Series A Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series A Preferred Units;

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(ii) approve any offering of Units or securities linked to Units, other than Profits Interest Units granted in accordance with this Agreement and the Equity Incentive Plan;

(iii) authorize or create (by reclassification, merger or otherwise) or issue or obligate itself to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security) having rights, preferences or privileges with respect to distributions, redemption or payments upon liquidation senior to or on a parity with the Series A Preferred Units;

(iv) effect any sale of substantially all of the assets of the Company or any of its subsidiaries, or any merger or acquisition, unless, in the case of such merger or acquisition, the Company would not be required to increase its Units by more than twenty percent (20%) or use more than twenty percent (20%) of its assets in such merger or acquisition;

(v) increase the size of the Board of Managers to a number greater than five (5) Managers;

(vi) repurchase Common Units, other than from Managers, officers, employees, consultants, placement agents or other service providers of the Company or its subsidiaries upon termination of their employment or services;

(vii) except as expressly provided herein, declare or pay any Distribution with respect to the Preferred Units or Common Units;

(viii) incur any indebtedness for borrowed money in excess of $10,000,000 other than Permitted Indebtedness;

(ix) authorize the conversion of the legal form of the Company to a corporation or to elect to cause the Company to be treated as a corporation for U.S. tax purposes;

(x) voluntarily liquidate or dissolve; or

(xi) amend this Section 5.05(a).

(b) Following the Option Expiration Date and during such time as (x) any Loan under the Bridge Loan Agreement shall be outstanding and (y) at least twenty five million (25,000,000) Series A Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the Series A Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action

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would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series A Preferred Units, provided, however, that the authorization or creation (by reclassification, merger or otherwise) or issuance or the incurrence of an obligation to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security), whether senior or junior to, or on a parity with, the Series A Preferred Units, in each case, which complies with the restrictions set forth in clause (ii) of this Section 5.05(b), shall not require such approval of the holders of Series A Preferred Units;

(ii) approve any offering of Units or securities linked to Units, other than (A) any Permitted Equity Offering or (B) Profits Interest Units granted in accordance with this Agreement and the Equity Incentive Plan;

(iii) authorize any sale of substantially all of the assets of the Company or any of its subsidiaries, or any merger or acquisition, unless, (A) in the case of such merger or acquisition, the Company would not be required to increase its outstanding stock by more than 20% or use more than 20% of its assets in such merger or acquisition, or (B) such sale, merger or acquisition would result in the full payment of amounts then owed by the Company under the Bridge Loan Agreement concurrently with the closing of such merger or acquisition;

(iv) repurchase Common Units, other than from Managers, officers, employees, consultants, placement agents or other service providers of the Company or its subsidiaries upon termination of their employment or services;

(v) except as expressly provided herein, declare or pay any Distribution with respect to the Preferred Units or Common Units;

(vi) incur any indebtedness in excess of $10,000,000 in the aggregate outstanding at any time (other than indebtedness under the Bridge Loan Agreement), other than the following types of indebtedness that may exceed such an amount: (A) unsecured indebtedness of the Company to Maxygen that is not senior to any indebtedness outstanding under the Bridge Loan Agreement; (B) Permitted Indebtedness; and (C) indebtedness which would result in the full payment of amounts then owed by the Company under the Bridge Loan Agreement concurrently with the closing of the transaction or series of transactions in which the Company incurs such indebtedness; or

(vii) amend this Section 5.05(b).

(c) Following the Option Expiration Date and during such time as (x) no Loan under the Bridge Loan Agreement shall be outstanding or (y) less than twenty five million (25,000,000) Series A Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the Series A Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action

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would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series A Preferred Units, provided, however, that the authorization or creation (by reclassification, merger or otherwise) or issuance or the incurrence of an obligation to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security), whether senior or junior to, or on a parity with, the Series A Preferred Units, shall not require such approval of the holders of Series A Preferred Units; or

(ii) amend this Section 5.05(c).

SECTION 5.06 Series B Preferred Unit Protective Provisions.

(a) Prior to the Option Expiration Date as long as at least five million (5,000,000) Series B Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the Series B Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series B Preferred Units;

(ii) approve any offering of Units or securities linked to Units, other than Profits Interest Units granted in accordance with this Agreement and the Equity Incentive Plan;

(iii) authorize or create (by reclassification, merger or otherwise) or issue or obligate itself to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security) having rights, preferences or privileges with respect to distributions, redemption or payments upon liquidation senior to or on a parity with the Series B Preferred Units;

(iv) authorize any sale of substantially all of the assets of the Company or any of its subsidiaries, or any merger or acquisition, unless, in the case of such merger or acquisition, the Company would not be required to increase its outstanding Units by more than twenty percent (20%) or use more than twenty percent (20%) of its assets in such merger or acquisition;

(v) increase the size of the Board of Managers to a number greater than five (5) Managers;

(vi) repurchase Common Units, other than from Managers, officers, employees, consultants, placement agents or other service providers of the Company or its subsidiaries upon termination of their employment or services;

(vii) except as expressly provided herein, declare or pay any Distribution with respect to the Preferred Units or Common Units;

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(viii) incur any indebtedness for borrowed money in excess of $10,000,000 other than Permitted Indebtedness;

(ix) authorize the conversion of the legal form of the Company to a corporation or to elect to cause the Company to be treated as a corporation for U.S. tax purposes;

(x) voluntarily liquidate or dissolve; or

(xi) amend this Section 5.06(a).

(b) Following the Option Expiration Date and during such time as (x) any Loan under the Bridge Loan Agreement shall be outstanding and (y) at least five million (5,000,000) Series B Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the outstanding Series B Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series B Preferred Units, provided, however, that the authorization or creation (by reclassification, merger or otherwise) or issuance or the incurrence of an obligation to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security), whether senior or junior to, or on a parity with, Series B Preferred Units, in each case, which complies with the restrictions ser forth in clause (ii) of this Section 5.06(b), shall not require such approval of the holders of Series B Preferred Units;

(ii) approve any offering of Units or securities linked to Units, other than (A) any Permitted Equity Offering or (B) Profits Interest Units granted in accordance with this Agreement and the Equity Incentive Plan;

(iii) authorize any sale of substantially all of the assets of the Company or any of its subsidiaries, or any merger or acquisition, unless, (A) in the case of such merger or acquisition, the Company would not be required to increase its outstanding Units by more than twenty percent (20%) or use more than twenty percent (20%) of its assets in such merger or acquisition, or (B) such sale, merger or acquisition would result in the full payment of amounts then owed by the Company under the Bridge Loan Agreement concurrently with the closing of such merger or acquisition;

(iv) repurchase Common Units, other than from Managers, officers, employees, directors, consultants, placement agents or other service providers of the Company or its subsidiaries upon termination of their employment or services;

(v) except as expressly provided herein, declare or pay any Distribution with respect to the Preferred Units or Common Units;

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(vi) incur any indebtedness in excess of $10,000,000 in the aggregate outstanding at any time (other than indebtedness under the Bridge Loan Agreement), other than the following types of indebtedness that may exceed such an amount: (A) unsecured indebtedness of the Company to Maxygen that is not senior to any indebtedness outstanding under the Bridge Loan Agreement; (B) Permitted Indebtedness; and (C) indebtedness which would result in the full payment of amounts then owed by the Company under the Bridge Loan Agreement concurrently with the closing of the transaction or series of transactions in which the Company incurs such indebtedness; or

(vii) amend this Section 5.06(b).

(c) Following the Option Expiration Date and during such time as (x) no Loan under the Bridge Loan Agreement shall be outstanding or (y) less than five million (5,000,000) Series B Preferred Units (as adjusted for Recapitalizations) shall be issued and outstanding, the Company shall not, without first obtaining the approval (by vote or written consent as provided by law) of the holders of more than fifty percent (50%) of the Series B Preferred Units:

(i) amend, alter or repeal any provision of this Agreement (including pursuant to a merger other than in connection with a bona fide sale of the Company) if such action would adversely alter the rights, preferences, privileges or powers of, or restrictions provided for the benefit of the Series B Preferred Units, provided, however, that the authorization or creation (by reclassification, merger or otherwise) or issuance or the incurrence of an obligation to issue any new class or series of equity security (including any security convertible into or exercisable for any equity security), whether senior or junior to, or on a parity with, Series B Preferred Units, shall not require such approval of the holders of Series B Preferred Units; or

(ii) amend this Section 5.06(c).

ARTICLE 6.

CAPITAL ACCOUNTS

SECTION 6.01 Capital Contributions.

(a) Initial Capital Accounts. Each Member shall have an initial Capital Account balance equal to the amount set forth as such Member’s Initial Capital Account Balance on Schedule A. Such initial Capital Account balances are a result of the following transactions: in the case of Maxygen, the contribution by Maxygen to the Company of certain assets, properties, rights, claims, liabilities and obligations on the terms and conditions set forth in the Asset Contribution Agreement followed by a cash investment by Maxygen in the Company; and, in the case of Bio, a cash investment by Maxygen in the Company. Except as specifically provided in this Agreement, no Person shall be permitted or required to make a Capital Contribution to the Company.

(b) Withdrawal and Return of Capital. Except as provided in Article VIII and Section 9.02, no Member shall be entitled to the return of such Member’s Capital Contribution, a Distribution in respect of such Member’s Capital Account balance, or any other Distribution in respect of such Member’s Unit.

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(c) Adjustment of Percentage Interests. Upon (i) the addition of a Member following the date hereof or (ii) the acceptance of Capital Contributions by the Company from a Member following contribution of such Member’s initial Capital Contribution, the Managing Member shall adjust the Percentage Interests of each Member, and shall accordingly update Schedule A hereto, so that the Percentage Interests of the Members take into account any such new Member or Capital Contributions.

SECTION 6.02 Interest on Capital. No Member shall be entitled to interest on such Member’s Capital Contribution, Capital Account balance, or share of unallocated Profits.

SECTION 6.03 Limitation of Liability; Return or Withholding of Certain Distributions. Except as otherwise required by applicable law, a Member shall have no obligation to restore a negative balance in such Member’s Capital Account and no personal liability for the debts and obligations of the Company. A Member shall have no liability to the Company or to any other Member in respect of a negative balance in such Member’s Capital Account during the term of the Company or at the conclusion of the Company’s winding up, and such negative balance shall not be considered a debt owed to the Company or to any other Person for any purpose whatsoever. A Member that receives a Distribution (a) in violation of this Agreement or (b) that is required to be returned to the Company under applicable law shall return such Distribution within thirty (30) days after demand therefor by any Member. Nothing in this Section 6.03 shall be applied to release any Member from (i) its obligation to make payments specifically required pursuant to this Agreement or (ii) its obligations pursuant to any relationship between the Company and such Member acting in a capacity other than as a Member (including, for example, as a borrower, employee or independent contractor).

ARTICLE 7.

PROFITS AND LOSSES

SECTION 7.01 Allocations of Profits and Losses of the Company . Except as otherwise provided in this Article 7, the items of Profits and Losses for each Fiscal Period shall be allocated as follows:

(a) Non-liquidity Events. Profits and Losses other than from a Liquidity Event shall be allocated among the Members in proportion to their Percentage Interests, assuming for purposes of this Section 7.01(a) as if no Common Units are outstanding.

(b) Liquidity Events. Profits and Losses from a Liquidity Event shall be allocated among the Members in proportion to their Percentage Interests after taking into account the Distribution Threshold for each Common Unit that is a Profits Interest Unit.

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SECTION 7.02 Allocation Adjustments to Comply with Section 704(b) of the Code.

(a) Limitation on Allocation of Losses. If an item of Losses otherwise allocable to a Member under Section 7.01 would cause such Member to have an Adjusted Capital Account Deficit at the end of any Fiscal Year (or increase the amount of such Member’s Adjusted Capital Account Deficit), the item shall not be allocated to such Member, but shall instead be specially allocated as follows:

(i) to the Members in proportion to their respective positive Capital Account balances, until the Capital Account balance of each Member has been reduced to (but not less than) zero; and

(ii) next, to the Members in proportion to their respective Percentage Interests.

(b) Qualified Income Offset. In the event any Member unexpectedly receives any adjustments, allocations or Distributions described in Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), (5) or (6), items of Company income and gain shall be specially allocated to each such Member in an amount and manner sufficient to eliminate, to the extent required by the Treasury Regulations, the Adjusted Capital Account Deficit of such Member as quickly as possible, provided that an allocation pursuant to this Section 7.02(b) shall be made only if and to the extent that such Member would have an Adjusted Capital Account Deficit after all other allocations provided for in this Article VII been tentatively made as if this Section 7.02(b) were not in this Agreement.

(c) Gross Income Allocation. In the event any Member has an Adjusted Capital Account Deficit at the end of any Fiscal Year, that Member shall be specially allocated items of Company income and gain in the amount of such excess as quickly as possible, provided that an allocation pursuant to this Section 7.02(c) shall be made only if and to the extent that the Member would have an Adjusted Capital Account Deficit in excess of such sum after all other allocations provided for in this Article VII have been made, as if Section 7.02(b) and this Section 7.02(c) were not in the Agreement.

(d) Member Nonrecourse Deductions. In accordance with the provisions of Treasury Regulation Section 1.704-2(i), each item of Member Nonrecourse Deduction shall be allocated among the Members in proportion to the economic risk of loss that the Members bear with respect to the nonrecourse liability of the Company to which such item of Member Nonrecourse Deduction is attributable.

(e) Minimum Gain Chargeback. This Section 7.02(e) hereby incorporates by reference the “minimum gain chargeback” provisions of Treasury Regulations Section 1.704-2. In general, upon a reduction of the Company’s Minimum Gain, the preceding sentence shall require that items of income and gain be allocated among the Members in a manner that reverses prior allocations of Member Nonrecourse Deductions as well as reductions in the Members’ Capital Account balances resulting from Distributions that, notwithstanding Section 7.04, are allocable to increases in the Company’s Minimum Gain. Subject to the provisions of Section 704 of the Code

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and the Treasury Regulations thereunder, if it is determined at any time in the reasonable discretion of the Managing Member in consultation with Bio prior to the Option Exercise Date that operation of such “minimum gain chargeback” provisions likely will not achieve such a reversal by the conclusion of the liquidation of the Company, such Members shall adjust the allocation provisions of this Article 7 as necessary to accomplish that result.

(f) Section 754 Adjustment. To the extent an adjustment to the adjusted tax basis of any Company asset pursuant to Code Section 734(b) or Code Section 743(b) is required, pursuant to Regulations Section 1.704-1(b)(2)(iv)(m), to be taken into account in determining Capital Accounts, the amount of such adjustment to the Capital Accounts shall be treated as an item of gain (if the adjustment increases the basis of the asset) or loss (if the adjustment decreases such basis) relating to the asset and such gain or loss shall be specially allocated to the Members in a manner consistent with the manner in which their Capital Accounts are required to be adjusted pursuant to such Treasury Regulations Section.

(g) Regulatory Allocations. The allocations set forth in Section 7.02(a) through Section 7.02(f) are intended to comply with certain regulatory requirements under the Code. The Members intend that, to the extent possible, all allocations made pursuant to such Sections will, over the term of the Company, be offset either with other allocations pursuant to Section 7.02(a) through Section 7.02(f) or with special allocations of other items of Company income, gain, loss or deduction pursuant to this Section 7.02(g) Accordingly, the Managing Member is hereby authorized and directed to make offsetting allocations of Company income, gain, loss or deduction under this Section 7.02(g) in whatever manner the Managing Member determines is appropriate so that, after such offsetting special allocations are made, the Capital Accounts of the Members are, to the extent possible, equal to the Capital Accounts each would have if the provisions of Section 7.02(a) through Section 7.02(f) were not contained in this Agreement and all Company income, gain, loss, and deduction were instead allocated in accordance with the provisions of Section 7.01.

SECTION 7.03 General Provisions Regarding Allocations and Capital Account Maintenance.

(a) Book – Tax Accounting Disparities. Solely for U.S. federal income tax purposes, if Company property is reflected in the Capital Accounts of the Members at a value that differs from the adjusted tax basis of such property (whether because such property was contributed or treated as contributed by a Member or because of a revaluation of the Members’ Capital Accounts under Treasury Regulations Section 1.704-1(b)), allocations of depreciation, amortization, income, gain or loss with respect to such property shall be made among the Members in a manner which takes such difference into account in accordance with Code Section 704(c) and the Treasury Regulations issued thereunder using the traditional allocation method set forth in Treasury Regulations Section 1.704-3(b); provided that, curative allocations of gain recognized on a disposition by the Company of assets, properties, rights and claims contributed by Maxygen pursuant to the Asset Contribution Agreement shall be made to the extent permitted in Treasury Regulations Section 1.704-3(c).

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(b) Allocations in Event of Transfer. If an interest in the Company is Transferred in accordance with this Agreement, allocations of Profits and Losses as between the transferor and transferee shall be made using any method selected by the Managing Member and permitted under Section 706 of the Code.

(c) Adjustments to Capital Accounts for Distributions of Property. If property distributed in kind is reflected in the Capital Accounts of the Members at a value that differs from the fair market value of the property at the time of Distribution, the difference shall be treated as Profits or Losses on the sale of the property and shall be allocated among the Members, as of the time immediately prior to such Distribution, in accordance with the provisions of this Article 7.

(d) Tax Credits and Similar Items. Any tax credits or similar items not allocable pursuant to Section 7.01, Section 7.02 and Section 7.03(a) through Section 7.03(c) shall be allocated to the Members in proportion to their respective Percentage Interests. Notwithstanding the preceding sentence, if Company expenditures that give rise to tax credits also give rise to Member Nonrecourse Deductions, the tax credits attributable to such expenditures shall be allocated in accordance with Treasury Regulations Section 1.704-1(b)(4)(ii).

(e) Reallocation of Certain Losses. To the extent that: (i) Losses that otherwise would have been allocated to a Member under this Section 7.03 were allocated to one or more other Members under Section 7.02(a) or any other provision of this Agreement that prohibits the allocation to a Member of Losses which would reduce such Member’s Capital Account (or Updated Capital Account) balance below a specified amount; (ii) such allocation has not been reversed pursuant to the subsequent operation of Section 7.02(a) or this Section 7.03(e); and (iii) the Member makes a Capital Contribution to the Company, the Capital Accounts of the Members shall be adjusted in connection with such return or Capital Contribution (to the extent of the value thereof) to effect a reallocation, in reverse order, of such Losses to the Member.

(f) Tax Allocations. Taking into account the requirements of this Article 7, items of Company income, gain, loss, deduction or credit recognized for U.S. federal income tax purposes shall be allocated among the Members for U.S. federal income tax purposes in a manner that is consistent with the requirements of the Code and the Treasury Regulations.

SECTION 7.04 Nonallocation of Distributions to Increases in Minimum Gain. To the extent permitted under Treasury Regulations Section 1.704-2(h), distributions to Members shall not be allocable to increases in the Company’s Minimum Gain. In general, and except as provided in such Treasury Regulation, the preceding sentence is intended to ensure that reductions in a Member’s Capital Account balance resulting from distributions of money or other property to that Member are not reversed by the minimum gain chargeback provisions of Section 7.02(e).

SECTION 7.05 Allocation of Liabilities. Solely for purposes of determining the Members’ respective shares of the nonrecourse liabilities of the Company within the meaning of Treasury Regulations Section 1.752-3(a)(3), each Member’s interest in Company Profits shall be equal to the ratio that such Member’s Percentage Interest bears to the aggregate Percentage Interests of all of the Members.

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SECTION 7.06 Modifications to Preserve Underlying Economic Objectives. In the event that (a) there is a change in the U.S. federal income tax law or (b) the Company borrows money or property, the Board of Managers, after consultation with the Company’s tax advisors, shall make the minimum modifications to the allocation provisions of this Agreement necessary to preserve the underlying economic objectives of the Members as reflected in this Agreement and, in the case of a borrowing, to properly allocate the tax items relating to such borrowing in accordance with the Code and the Treasury Regulations.

SECTION 7.07 Withholding Taxes.

(a) The Company shall withhold taxes from Distributions to, and allocations among, the Members to the extent required by law (as determined by the Managing Member in its reasonable discretion). Except as otherwise provided in this Section 7.07, any amount so withheld by the Company with regard to a Member shall be treated for purposes of this Agreement as an amount actually distributed to such Member pursuant to Article 8. An amount shall be considered withheld by the Company if, and at the time, remitted to a governmental agency, without regard to whether such remittance occurs at the same time as the distribution or allocation to which it relates; provided, however, that an amount actually withheld from a specific distribution, or designated by the Managing Member as withheld from a specific allocation, shall be treated as if distributed at the time such distribution or allocation occurs. Nothing in this Section 7.07(a) shall have any bearing on amounts withheld from a Member in respect of compensation paid or payable to such Member in such Member’s capacity as an employee of the Company or pursuant to a bona fide written employment agreement between such Member and the Company.

(b) If, pursuant to Section 7.07(a), an amount withheld with regard to a Member is treated for purposes of this Agreement as an amount distributed to such Member pursuant to Article 8, subsequent actual Distributions to such Member pursuant to Article 8 shall be reduced as necessary to, as quickly as possible, cause the aggregate Distributions to such Member over the term of the Company (including actual Distributions and Distributions deemed to have occurred pursuant to Section 7.07(a)) to equal the actual Distributions that would have been made to such Member if Section 7.07(a) were not part of this Agreement.

(c) Each Member hereby agrees to indemnify the Company and the other Members for any liability they may incur for failure to properly withhold taxes in respect of such Member; moreover, each Member hereby agrees that neither the Company nor any other Member shall be liable for any excess taxes withheld in respect of such Member’s Membership Interest and that, in the event of overwithholding otherwise permitted by this Agreement, a Member’s sole recourse shall be to apply for a refund from the appropriate governmental authority.

SECTION 7.08 Intent of Allocations. The parties intend that the foregoing allocation provisions of this Article 7 shall produce final Capital Account balances of the Members that will permit liquidating Distributions made in accordance with final Capital Account balances to be made in a manner identical to the order of priorities set forth in Section 8.02. To the extent that the allocation provisions of this Article 7 would fail to produce such final Capital Account balances, (a) such provisions shall be amended by the Board of Managers if and to the extent necessary to

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produce such result and (b) income and loss of the Company for prior open years (including items of gross income and deduction of the Company for such years) shall be reallocated by the Board of Managers among the Members to the extent it is not possible to achieve such result with allocations of items of income (including gross income) and deduction for the current year and future years, as approved by the Board of Managers. This Section 7.08 shall control notwithstanding any reallocation or adjustment of taxable income, taxable loss, or items thereof by the Internal Revenue Service or any other taxing authority. The Board of Managers shall have the power to amend this Agreement without the consent of the other Members, as it reasonably considers advisable, to make the allocations and adjustments described in this Section 7.08.

ARTICLE 8.

DISTRIBUTIONS; ASSETS SALES

SECTION 8.01 Distributions. The Board of Managers may declare Distributions to the Members holding Preferred Units or Common Units that are not Profits Interest Units other than upon the occurrence of a Liquidity Event in proportion to their respective Percentage Interests annually; provided that such Distributions may only be declared in an amount sufficient for each Member to pay any taxes owed with respect to the taxable income allocated to any Units held by such Member in accordance with Article 7 as reasonably determined by the Board of Managers.

SECTION 8.02 Liquidity Event Distributions.

(a) Upon the occurrence of a Liquidity Event and subject to Sections 18-607 and 18-804 of the Delaware Act, either voluntary or involuntary, the Members holding Preferred Units shall be entitled to receive, on a pari passu basis and prior and in preference to any Distribution of any of the assets of the Company to the holders of Common Units by reason of their ownership of such Common Units, an amount per Preferred Unit held by them equal to the sum of (x) the Liquidation Preference for such Preferred Unit and (y) all declared but unpaid Distributions (if any) on such Preferred Unit (including all accrued but unpaid Distributions on such Preferred Unit at the Annual Distribution Rate) or, with respect to any series of Preferred Units, such lesser amount as may be approved by the consent or vote of the holders of a majority of the outstanding Preferred Units of such series. If upon the occurrence of the Liquidity Event, the assets of the Company legally available for distribution to the holders of Preferred Units are insufficient to permit the payment to such holders of the full amounts specified in this Section 8.02(a), then all assets of the Company legally available for distribution to Members shall be distributed with equal priority and pro rata among each of the of Preferred Units in proportion to the full amounts the Members would otherwise be entitled to receive pursuant to this Section 8.02(a). With respect to each series of Preferred Units, the treatment of any transaction or series of related transactions as a Liquidity Event pursuant to clause (a) or (b) of definition of “Liquidity Event” may be waived by the consent or vote of the holders of a majority of such series of Preferred Units. After the payment to the holders of Preferred Units of the full preferential amounts specified above, the remaining assets of the Company legally available for distribution to the Members by the Company shall be distributed with equal priority and pro rata among the holders of the Preferred Units and Common Units in

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proportion to the number of Common Units held by them, with the Preferred Units being treated for this purpose as if they had been converted to Common Units at the then applicable Conversion Rate; provided, however, that notwithstanding the foregoing, Profits Interest Units shall be entitled to and receive distributions in connection with any Liquidity Event only if and to the extent provided for in, and subject to the terms of, the Equity Incentive Plan. For the avoidance of doubt, Distributions made in connection with any Liquidity Event that consists of or results in the liquidation and winding up of the Company shall be subject to Section 9.02.

(b) If any assets of the Company distributed to Members in connection with any Liquidity Event are other than cash, then the value of such assets shall be their fair market value as determined in good faith by the Board of Managers, except that any publicly-traded securities to be distributed to Members in a Liquidity Event shall be valued as follows:

(i) if the securities are then traded on a national securities exchange, then the value of the securities shall be deemed to be the average of the closing prices of the securities on such exchange over the ten (10) trading day period ending five (5) trading days prior to the Distribution;

(ii) if the securities are actively traded over-the-counter, then the value of the securities shall be deemed to be the average of the closing bid prices of the securities over the ten (10) trading day period ending five (5) trading days prior to the Distribution.

In the event of a merger or other acquisition of the Company by another entity, the Distribution date shall be deemed to be the date such transaction closes.

For the purposes of this Section 8.02(b), “trading day” shall mean any day which the exchange or system on which the securities to be distributed are traded is open and “closing prices” or “closing bid prices” shall be deemed to be: (i) for securities traded primarily on the New York Stock Exchange, the American Stock Exchange or a Nasdaq market, the last reported trade price or sale price, as the case may be, at 4:00 p.m., New York time, on that day and (ii) for securities listed or traded on other exchanges, markets and systems, the market price as of the end of the regular hours trading period that is generally accepted as such for such exchange, market or system. If, after the date hereof, the benchmark times generally accepted in the securities industry for determining the market price of a stock as of a given trading day shall change from those set forth above, the fair market value shall be determined as of such other generally accepted benchmark times.

ARTICLE 9.

DISSOLUTION; TAX MATTERS; CONVERSION TO CORPORATION

SECTION 9.01 Dissolution. The Company shall dissolve upon the first to occur of the following:

(a) subject to Section 5.05(a)(x) and Section 5.06(a)(x), the approval of the Members then holding a majority of the outstanding Common Units (with the Preferred Units being treated for this purpose as if they had been converted to Common Units at the then applicable Conversion Rate) to dissolve the Company;

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(b) at any time there are no Members unless the Company is continued without dissolution in accordance with the Delaware Act; and

(c) the entry of a decree of dissolution under Section 18-802 of the Delaware Act.

The Company shall terminate when all its assets, after payment of or due provision for all debts, liabilities and obligations of the Company, shall have been distributed to the Members in the manner provided for in Article 7 and the Certificate of Formation shall have been canceled in the manner required by the Delaware Act.

SECTION 9.02 Liquidation.

(a) Following dissolution pursuant to Section 9.01, all the business and affairs of the Company shall be liquidated and wound up. The Board of Managers shall act as liquidating trustee and wind up the affairs of the Company pursuant to this Agreement.

(b) The proceeds of the liquidation of the Company will be distributed:

(i) first, to creditors of the Company (including Members who are creditors), to the extent otherwise permitted by law in satisfaction of all the Company’s debts and liabilities (whether by payment or by making reasonable provision for payment thereof), and

(ii) second, to the Members in accordance with the principles of Section 8.02(a).

SECTION 9.03 Tax Matters.

(a) Tax Matters Partner. The Managing Member is hereby designated the “tax matters partner” of the Company within the meaning of Section 6231(a)(7) of the Code. Except to the extent specifically provided in the Code or the Treasury Regulations (or the laws of relevant non-U.S. federal taxing jurisdictions), the Managing Member shall have exclusive authority to act for or on behalf of the Company with regard to tax matters, including the authority to make (or decline to make) any available tax elections; provided that, notwithstanding the preceding clause, the Company shall make an election under Section 754 of the Code with respect to its first taxable year. Notwithstanding the foregoing and the authority generally granted to the tax matters partner by the provisions of the Code, the tax matters partner shall not, without the consent of Bio (such consent not to be unreasonably withheld or delayed) (i) enter into a settlement of a partnership administrative adjustment binding on Bio; (ii) agree to an extension of the period of limitations on the assessment of tax; or (iii) request an administrative adjustment within the meaning of Code Section 6227. At the request of Bio, the tax matters partner shall file and prosecute on behalf, and at the expense, of Bio, a petition for judicial review of a final partnership administrative adjustment or a petition for judicial review of an administrative adjustment request not fully allowed. In the case of a judicial review of

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a final partnership administrative adjustment or an administrative adjustment request not fully allowed, such petition shall be filed in such applicable court as Bio shall select, or if Bio shall fail to so elect, in the United States Tax Court.

(b) Partnership for Tax Purposes. Except to the extent otherwise required by applicable law (disregarding for this purpose any requirement that can be avoided through the filing of an election or similar administrative procedure), the Managing Member shall cause the Company to take the position that the Company is a “partnership” for U.S. federal, state and local income tax purposes and shall cause to be filed with the appropriate tax authorities any elections or other documents necessary to give due legal effect to such position. A Member shall not file (and each Member hereby represents that it has not filed) any income tax election or other document that is inconsistent with the Company’s position regarding its classification as a “partnership” for applicable federal, state and local income tax purposes. The Members expressly do not intend hereby to form a partnership except insofar as the Company may be treated as a partnership solely for tax purposes.

(c) Notice of Inconsistent Treatment of Company Item; Notice of Settlement. No Member shall file a notice with the U.S. Internal Revenue Service under Section 6222(b) of the Code in connection with such Member’s intention to treat an item on such Member’s U.S. federal income tax return in a manner which is inconsistent with the treatment of such item on the Company’s U.S. federal income tax return unless such Member has, at least thirty (30) days prior to the filing of such notice (or such shorter period as is approved by the Managing Member in its sole and absolute discretion), provided the Managing Member with a copy of the notice and thereafter in a timely manner provides such other information related thereto as the Managing Member shall reasonably request. Any Member entering into a settlement agreement with the U.S. Department of the Treasury or the U.S. Internal Revenue Service that concerns a Company item shall notify the Managing Member of such settlement agreement and its terms within sixty (60) days after the date thereof.

(d) Tax Return Information. Within ninety (90) days after the end of each Fiscal Year, the Company shall supply all information reasonably necessary to enable the Members to prepare their U.S. federal income tax returns including, without limitation, Schedules K-1, and (upon request therefor) to comply with other reporting requirements imposed by law.

SECTION 9.04 Conversion to a Corporation. Following the Option Expiration Date, the Board of Managers shall have the right to authorize the conversion of the legal form of the Company to a corporation in accordance with Section 18-216 of the Delaware Act without the need for any action or consent of any Member. Upon such conversion, each Unit will be converted into one share of common stock or preferred stock (which may be divided into one or more series or subseries) which shall have rights that are equivalent in all material respects to the rights of the respective Units and which shall be subject to no additional restrictions or limitations other than those applicable to such Units prior to such conversion, in each case as determined reasonably and in good faith by the Board of Managers. Notwithstanding anything to the contrary in the foregoing sentence, if the Board of Managers authorizes the conversion of the legal form of the Company to a corporation, at

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the option of Bio, the Members and the Board of Managers agree to use commercially reasonable good faith efforts to structure any transaction to incorporate the Company (or to take such other action as the Board of Managers may deem advisable) as a tax-deferred transaction for U.S. federal income tax purposes and will cooperate in good faith and in a commercially reasonable manner in attempting to achieve a resulting corporate structure that is tax efficient for the parties, for example, a structure in which Bio and/or Maxygen (or its shareholders) own direct interests in the newly-created corporation upon the completion of any transaction.

ARTICLE 10.

MISCELLANEOUS

SECTION 10.01 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent by electronic mail or otherwise delivered by hand, messenger or courier service addressed:

If to Maxygen or the Company
addressed to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	Email: corporatesecretary@maxygen.com
with copy to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: General Counsel
	Telephone: (650) 298-5300
	Email: corporatesecretary@maxygen.com
and a copy to:	Wilson Sonsini Goodrich & Rosati
	Professional Corporation
	650 Page Mill Road
	Palo Alto, CA 94304-1050
	USA
	Attention: Tony Jeffries
	Telephone: (650) 493-9300
	Email: tjeffries@wsgr.com

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If to the Bio,
addressed to:	Astellas Pharma Inc.
	3-11, Nihonbashi-Honcho 2-chome
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Business Development
	Telephone: (813) 3244-2500
	Email: masaki.doi@jp.astellas.com
with a copy to:	Astellas Pharma Inc.
	3-11, Nihonbashi-Honcho 2-chome
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Legal
	Telephone: (813) 3244-3231
	Email: kazunori.okimura@jp.astellas.com
with a copy to:	Morrison & Foerster LLP
	1290 Avenue of the Americas
	New York, NY 10104
	Attention: Michael O. Braun, Esq.
	Telephone: (212) 468-8000
	Email: mbraun@mofo.com

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given (i) if delivered by hand, messenger or courier service, when delivered (or if sent via a nationally-recognized overnight courier service, freight prepaid, specifying next-business-day delivery, one Business Day after deposit with the courier), (ii) if sent via registered or certified mail, at the earlier of its receipt or five days after the same has been deposited in a regularly-maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid, or (iii) if sent via electronic mail, when directed to the relevant electronic mail address, if sent during normal business hours of the recipient, or if not sent during normal business hours of the recipient, then on the recipient’s next Business Day.

(b) Whenever notice is required to be given, under the Delaware Act or this Agreement, to any Person with whom communication is unlawful, the giving of such notice to such Person shall not be required and there shall be no duty to apply to any governmental authority or agency for a license or permit to give such notice to such Person. Any action or meeting which shall be taken or held without notice to any such Person with whom communication is unlawful shall have the same force and effect as if such notice had been duly given.

(c) Whenever notice is required to be given under any provision of the Delaware Act or this Agreement, a written waiver, signed by the Person entitled to notice, or a waiver by electronic transmission by the Person entitled to notice, whether before or after the time of the event for which notice is to be given, shall be deemed equivalent to notice. Attendance of a Person at a

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meeting shall constitute a waiver of notice of such meeting, except when the Person attends a meeting for the express purpose of objecting at the beginning of the meeting, to the transaction of any business because the meeting is not lawfully called or convened. Neither the business to be transacted at, nor the purpose of, any meeting of the Members need be specified in any written waiver of notice or any waiver by electronic transmission unless so required by this Agreement.

(d) Each Member hereby consents to the delivery of any notice to Members given by the Company under this Agreement, the Delaware Act, or the Certificate of Formation by (i) electronic mail to the electronic mail address set forth above (or to any other electronic mail address for the Member in the Company’s records), (ii) posting on an electronic network together with separate notice to the Member of such specific posting, or (iii) any other form of electronic transmission (as defined in § 18-302 of the Delaware Act) directed to the Member. This consent shall be revocable by a Member by written notice to the Company. This consent shall be deemed revoked if (i) the Company is unable to deliver by electronic transmission two (2) consecutive notices given by the Company in accordance with this consent, and (ii) such inability becomes known to the secretary or assistant secretary of the Company or to the transfer agent, or other person responsible for the giving of notice; provided, however, the inadvertent failure to treat such inability as a revocation shall not invalidate any meeting or other action.

SECTION 10.02 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party upon any breach or default of any other party shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any kind or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party to this Agreement, shall be cumulative and not alternative.

SECTION 10.03 Successors and Assigns. This Agreement, and any and all rights, duties and obligations hereunder, shall not be assigned, transferred, delegated or sublicensed by any Member without the prior written consent of the other Members, provided that this Agreement may without requiring the consent of any other Member be assigned, transferred, delegated or sublicensed in connection with a transfer of the Units to (i) an entity that acquires all or substantially all of the business or assets of such Member, whether by merger, reorganization, acquisition, asset sale or otherwise, or (ii) a Related Entity of such Member, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement and, prior to the Option Expiration Date, the Preferred Unit Agreements. Any attempt by a Member without such permission to assign, transfer, delegate or sublicense any rights, duties or obligations that arise under this Agreement shall be void. Subject to the foregoing and except as otherwise provided herein, the provisions of this Agreement shall inure to the benefit of, and be binding upon, the successors, assigns, heirs, executors and administrators of the parties.

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SECTION 10.04 Severability. If any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Agreement, and such court will replace such illegal, void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Agreement shall be enforceable in accordance with its terms.

SECTION 10.05 Counterparts. This Agreement may be executed and delivered by facsimile (including by .pdf signature) and in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

SECTION 10.06 Entire Agreement. This Agreement and the exhibits and schedules hereto and the Transaction Agreements constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof and thereof. No party hereto shall be liable or bound to any other party in any manner with regard to the subjects hereof or thereof by any warranties, representations or covenants except as specifically set forth herein or therein.

SECTION 10.07 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of Delaware as applied to agreements entered into among Delaware residents to be performed entirely within Delaware, without regard to principles of conflicts of law that would result in the law of a jurisdiction other than the State of Delaware governing. In the event of a conflict between any provision of this Agreement and any non-mandatory provision of the Delaware Act, the provisions of this Agreement shall control and take precedence.

SECTION 10.08 Jurisdiction; Venue. With respect to any disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, any court in the State of Delaware having subject matter jurisdiction (or in the event of exclusive federal jurisdiction, the courts of the District of Delaware).

SECTION 10.09 Amendments. Subject to Section 5.05 and Section 5.06, this Agreement and any term hereof may be amended, waived, discharged or terminated only by a written instrument referencing this Agreement and signed by the Members holding a majority of the outstanding units voting together (with Profits Interest Units not voting); provided, however, that Members purchasing Units on or after the Option Expiration Date and Additional Members who acquire Units (including Profits Interest Units) in accordance with Section 3.01(b) may become parties to this Agreement by executing a counterpart of this Agreement (or, in the case of recipients of Profits Interest Units, the applicable Profits Interest Unit Agreement) without any amendment of this Agreement pursuant to this paragraph or any consent or approval of any other Member. Any such amendment, waiver, discharge or termination effected in accordance with this paragraph shall be binding upon each Member and each future holder of all such securities of such Member. Each Member acknowledges that by the operation of this paragraph, the Members will have the right and power to diminish or eliminate all rights of such Member under this Agreement.

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SECTION 10.10 Construction. The construction of this Agreement shall not take into consideration the Party who drafted or whose representative drafted any portion of this Agreement, and no canon of construction shall be applied that resolves ambiguities against the drafter of a document. Each Party acknowledges that: (a) it has read this Agreement; (b) it has been represented in the preparation, negotiation and execution of this Agreement by legal counsel of its own choice or has voluntarily declined to seek such counsel; and (c) it understands the terms and consequences of this Agreement and is fully aware of the legal and binding effect of this Agreement.

[Signature page follows]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first stated above.

PERSEID THERAPEUTICS LLC
By	/s/ Grant Yonehiro
Name:	Grant Yonehiro
Title:	CEO & President
ASTELLAS BIO INC.
By	/s/ Kazunori Okimura
Name:	Kazunori Okimura
Title:	Secretary
MAXYGEN, INC.
By	/s/ Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

[Signature page to Limited Liability Company Agreement of Perseid Therapeutics LLC)

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Schedule A

Members, Units and Initial Capital Account Balance

Name	Series A Preferred Units	Series B Preferred Units	Initial Capital Account Balance
Astellas Bio Inc.	—	10,000,000	$	10,000,000.00
Maxygen, Inc.	50,000,000	—	$	50,000,000.00

EX-2.1.4

Exhibit 2.1.4

SERIES A AND SERIES B PREFERRED UNIT PURCHASE AGREEMENT

by and among

Maxygen, Inc., a Delaware Corporation

Astellas Bio Inc., a Delaware Corporation

and Perseid Therapeutics LLC, a Delaware Limited Liability Company

Dated as of September 18, 2009

TABLE OF CONTENTS

		Page
ARTICLE 1	Purchase and Sale of Preferred Units	1
1.1	Sale and Issuance of Series A and Series B Preferred Units	1
1.2	Closing; Delivery	2
1.3	Use of Proceeds	2
ARTICLE 2	Representations, Warranties and Covenants of the Company	2
2.1	Organization and Operation	2
2.2	Capitalization	2
2.3	Authority	3
2.4	Valid Issuance of Units	3
2.5	Governmental Approvals	4
2.6	Company Documents	4
ARTICLE 3	Representations, Warranties and Covenants of the Purchasers	4
3.1	Incorporation by Reference	4
3.2	Purchase Entirely for Own Account	4
3.3	Investment Experience; Speculative Nature of Investment	4
3.4	Disclosure of Information	5
3.5	Restricted Securities	5
3.6	No Public Market	5
3.7	Reliance by the Company	5
3.8	Legends	5
3.9	Accredited Investor	6
3.10	No General Solicitation	6
3.11	Tax Advisors	6
ARTICLE 4	Closing Matters	6
ARTICLE 5	Miscellaneous	6
5.1	Survival of Representations, Warranties and Covenants	6
5.2	Indemnification; Sole Remedy; Dispute Resolution	7
5.3	Successors and Assigns	7
5.4	Governing Law	7
5.5	Counterparts	7

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TABLE OF CONTENTS

(continued)

		Page
5.6	Titles and Subtitles	7
5.7	Notices	8
5.8	No Finder’s Fees	9
5.9	Amendments and Waivers	10
5.10	Severability	10
5.11	Delays or Omissions	10
5.12	Entire Agreement	10
5.13	Interpretation	10

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SERIES A AND SERIES B PREFERRED UNIT PURCHASE AGREEMENT

THIS SERIES A AND SERIES B PREFERRED UNIT PURCHASE AGREEMENT is made as of the 18 day of September, 2009 by and among Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), on the one hand, and Maxygen, Inc., a Delaware corporation (“Maxygen”), and Astellas Bio Inc., a Delaware corporation (“Bio,” and together with Maxygen, the “Purchasers”), on the other hand. All capitalized terms used and not defined herein shall have such meanings as set forth in the Master Joint Venture Agreement among Maxygen, Bio, and Astellas Pharma Inc., a Japanese corporation, dated as of June 30, 2009 (the “Joint Venture Agreement”).

RECITALS

WHEREAS, the Purchasers are parties to the Joint Venture Agreement, and it is a condition to the closing of the transactions contemplated by such Joint Venture Agreement that the Company and the Purchasers execute and deliver this Agreement.

WHEREAS, the purchase and sale of the Units pursuant hereto shall be effectuated, first, by the contribution of certain Maxygen assets to the Company in exchange for equity in the Company and, immediately following the contribution of such assets to the Company, on Bio’s and Maxygen’s contribution of cash to the Company in exchange for equity in the Company.

NOW THEREFORE, the parties hereby agree as follows:

ARTICLE 1

PURCHASE AND SALE OF PREFERRED UNITS

1.1 Sale and Issuance of Series A and Series B Preferred Units.

(a) Subject to the terms and conditions of this Agreement, Maxygen agrees to purchase at the Closing (as defined below), and the Company agrees to sell and issue to Maxygen at the Closing, TEN MILLION (10,000,000) Series A Preferred Units (the “Series A Preferred Units”), at a purchase price of $1.00 per unit for an aggregate purchase price of TEN MILLION U.S. Dollars ($10,000,000), and FORTY MILLION (40,000,000) Series A Preferred Units in exchange for the Contributed Assets in a transaction intended to qualify as a tax-free exchange under Section 351 of the Code. The Series A Preferred Units issued to Maxygen pursuant to this Agreement shall be referred to as the “Series A Units.”

(b) Subject to the terms and conditions of this Agreement, Bio agrees to purchase at the Closing, and the Company agrees to sell and issue to Bio at the Closing, TEN MILLION (10,000,000) Series B Preferred Units (the “Series B Preferred Units”), at a purchase price of $1.00 per unit for an aggregate purchase price of TEN MILLION U.S. Dollars ($10,000,000). The Series B Preferred Units issued to Bio pursuant to this Agreement shall be referred to as the “Series B Units,” and, along with the Series A Units, as the “Units.”

1.2 Closing; Delivery.

(a) The closing of the transactions contemplated by this Agreement (the “Unit Purchase”) shall take place at the Closing as specified in Section 3.1 of the Joint Venture Agreement.

(b) At the Closing, the Company shall deliver to each Purchaser a certificate representing the Units being purchased by such Purchaser at such Closing against payment of the purchase price therefor by check payable to the Company or by wire transfer to a bank account designated by the Company (for the Units to be purchased by cash) or by transfer of the Contributed Assets pursuant to the Asset Contribution Agreement (for the Units to be purchased by contribution of the Contributed Assets), all as set forth in Section 1.1.

1.3 Use of Proceeds. The Company will use the proceeds from the sale of the Units for general corporate purposes.

ARTICLE 2

REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY

The Company hereby represents, warrants and covenants to each Purchaser that, except as set forth on the Disclosure Schedule attached as Exhibit A to this Agreement, which exceptions shall be deemed to be part of the representations, warranties and covenants made hereunder, the following representations are true and complete as of the date of the Closing, except as otherwise indicated.

2.1 Organization and Operation. The Company is a limited liability company duly formed, validly existing and in good standing under the laws of the State of Delaware, the jurisdiction of its formation. The Company has not conducted any business operations prior to the date hereof.

2.2 Capitalization. The authorized capital of the Company (the “Company Units”) consists, immediately prior to the Closing, of:

(a) Seventy-five million (75,000,000) common units (the “Common Units”), none of which are issued and outstanding. All of the outstanding Common Units have been duly authorized, are fully paid and non-assessable and have been issued in compliance with all applicable federal and state securities laws.

(b) Sixty million (60,000,000) preferred units (the “Preferred Units”), of which fifty million (50,000,000) units have been designated Series A Preferred Units and ten million (10,000,000) units have been designated Series B Preferred Units, none of which are issued and outstanding immediately prior to Closing. The rights, privileges and preferences of the Preferred Units are as stated in the LLC Agreement and as provided by the Limited Liability Company Act of the State of Delaware (the “LLCA”). Immediately following the Closing, the only issued and outstanding Company Units will be all of the Preferred Units.

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(c) The Company has reserved fifteen million (15,000,000) Common Units for issuance to officers, managers, employees and consultants of the Company pursuant to the Equity Incentive Plan duly adopted by the Board of Managers and approved by the Company’s members. All such reserved Common Units remain available for issuance to officers, managers, employees and consultants pursuant to the Equity Incentive Plan. The Company has furnished to the Purchasers complete and accurate copies of the Equity Incentive Plan and forms of agreements to be used thereunder.

(d) Except for (i) the conversion privileges of the Units to be issued under this Agreement and (ii) the rights provided in the LLC Agreement and the Transaction Agreements, there are no outstanding options, warrants, rights (including conversion or preemptive rights and rights of first refusal or similar rights) or agreements, orally or in writing, to purchase or acquire from the Company any Common Units, Series A Preferred Units or Series B Preferred Units, or any securities convertible into or exchangeable for Common Units, Series A Preferred Units or Series B Preferred Units.

(e) Except as set forth in Section 2.2 of the Disclosure Schedule, none of the Company’s unit purchase agreements or unit award documents contains or will contain a provision for acceleration of vesting (or lapse of a repurchase right) or other changes in the vesting provisions or other terms of such agreement or understanding upon the occurrence of any event or combination of events. Except as set forth in the LLC Agreement or the Equity Incentive Plan, the Company has no obligation (contingent or otherwise) to purchase or redeem any of its membership units.

2.3 Authority. The Company has all necessary power and authority to execute and deliver this Agreement, to perform its obligations hereunder and thereunder and to consummate the Unit Purchase. The execution and delivery of this Agreement and the consummation by the Company of the Unit Purchase have been duly and validly authorized by all requisite action, and no other proceedings on the part of the Company are necessary to authorize this Agreement or to consummate the Unit Purchase. At the Closing, this Agreement will (a) be duly and validly executed and delivered by the Company and (b) constitute the legal, valid and binding obligations of the Company, enforceable against the Company in accordance with its terms, except as may be limited by bankruptcy, insolvency, reorganization, moratorium and other similar laws and equitable principles related to or limiting creditors’ rights generally, by the availability of equitable remedies and defenses, and to the extent the indemnification provisions contained in the Investors’ Rights Agreement may further be limited by applicable laws and principles of public policy.

2.4 Valid Issuance of Units. The Units, when issued, sold and delivered in accordance with the terms and for the consideration set forth in this Agreement, will be validly issued, fully paid and non-assessable and free of restrictions on transfer other than restrictions on transfer under the Transaction Agreements, applicable Legal Requirements and Encumbrances created by or imposed by a Purchaser. Assuming the accuracy of the representations of the Purchasers in Article 3 of this Agreement and subject to the filings described in Section 2.5 below, the Units will be issued in compliance with all applicable Legal Requirements. The Common Units issuable upon conversion of the Units have been duly reserved for issuance, and upon issuance in accordance with the terms of the LLC Agreement, will be validly issued, fully

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paid and non-assessable and free of restrictions on transfer other than restrictions on transfer under the Transaction Agreements, applicable Legal Requirements and Encumbrances created by or imposed by a Purchaser. Based in part upon the representations of the Purchasers in Article 3 of this Agreement, and subject to Section 2.5 below, the Common Units issuable upon conversion of the Units will be issued in compliance with all applicable Legal Requirements.

2.5 Governmental Approvals. Assuming the accuracy of the representations made by the Purchasers in Article 3 of this Agreement, no Governmental Approval is required on the part of the Company in connection with the consummation of the Unit Purchase, except for (a) the filing of the Certificate, which will have been filed as of the Closing, and (b) filings pursuant to applicable federal and state securities laws, which have been or will be made in a timely manner.

2.6 Company Documents. The Certificate and the LLC Agreement are in the form provided to the Purchasers. The copy of the minute books of the Company provided to the Purchasers contains minutes of all meetings of managers and members and all actions by written consent without a meeting by the managers and members since the date of formation and accurately reflects in all material respects all actions by the managers (and any committee of managers) and members with respect to all transactions referred to in such minutes.

ARTICLE 3

REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE PURCHASERS

Each Purchaser hereby represents, warrants and covenants to the Company, severally and not jointly, and with respect only to such Purchaser, that:

3.1 Incorporation by Reference. The representations, warranties and covenants set forth in Section 4.1 of the Joint Venture Agreement (with respect to Maxygen) and Section 4.2 of the Joint Venture Agreement (with respect to Bio) are hereby incorporated by reference as if fully set forth herein.

3.2 Purchase Entirely for Own Account. The Purchaser hereby confirms that the Units to be acquired by the Purchaser will be acquired for investment for the Purchaser’s own account, not as a nominee or agent, and not with a view to the resale or distribution of any part thereof, and that the Purchaser has no present intention of selling, granting any participation in, or otherwise distributing the same. The Purchaser does not presently have any contract, undertaking, agreement or arrangement of any nature with any Person to sell, transfer or grant participations to such Person or to any third Person, with respect to any of the Units. The Purchaser has not been formed for the specific purpose of acquiring the Units.

3.3 Investment Experience; Speculative Nature of Investment. The Purchaser is able to fend for itself, can bear the economic risk of owning the Units, and has such knowledge and experience in financial or business matters that it is capable of evaluating the merits and risks of owning the Units. The Purchaser understands and acknowledges that the Company has no financial and operating history and that an investment in the Company is highly speculative and involves substantial risks. The Purchaser is able, without impairing its financial condition, to hold the Units for an indefinite period of time and to suffer a complete loss of such investment in the Company.

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3.4 Disclosure of Information. The Purchaser has had an opportunity to discuss the Company’s business, management, financial affairs and the terms and conditions of the offering of the Units with the Company’s management and has had an opportunity to review the Company’s facilities. The foregoing, however, does not limit or modify the representations, warranties or covenants of the Company in Article 2 of this Agreement or the right of the Purchasers to rely thereon.

3.5 Restricted Securities. The Purchaser understands that the Units and the Common Units issuable upon conversion of the Units (the “Conversion Units”) have not been, and will not be, registered under the Securities Act, by reason of a specific exemption from the registration provisions of the Securities Act which depends upon, among other things, the bona fide nature of the investment intent and the accuracy of the Purchaser’s representations as expressed herein. The Purchaser understands that the Units and the Conversion Units are “restricted securities” under applicable U.S. federal and state securities laws and that, pursuant to these laws, the Purchaser must hold the Units and the Conversion Units indefinitely unless they are registered with the Securities and Exchange Commission and qualified by state authorities, or an exemption from such registration and qualification requirements is available. The Purchaser acknowledges that the Company has no obligation to register or qualify the Units, or the Conversion Units, for resale except as set forth in the Investors’ Rights Agreement. The Purchaser further acknowledges that if an exemption from registration or qualification is available, it may be conditioned on various requirements, including, but not limited to, the time and manner of sale, the holding period for the Units, and on requirements relating to the Company which are outside of the Purchaser’s control, and which the Company is under no obligation and may not be able to satisfy.

3.6 No Public Market. The Purchaser understands that no public market now exists for the Units or the Conversion Units, and that the Company has made no assurances that a public market will ever exist for the Units or the Conversion Units.

3.7 Reliance by the Company. The Purchaser understands that the representations, warranties and covenants set forth in this Article 3 constitute a material inducement to the Company to enter into this Agreement.

3.8 Legends. The Purchaser understands that the Units and any securities issued in respect of or exchange for the Units, will bear the following legend:

THE UNITS REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. THESE UNITS MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED EXCEPT AS PERMITTED UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS PURSUANT TO REGISTRATION OR AN EXEMPTION THEREFROM. THE ISSUER OF THESE UNITS MAY REQUIRE AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE ISSUER

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THAT SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION OTHERWISE COMPLIES WITH THE ACT AND ANY APPLICABLE STATE SECURITIES LAWS.

THE UNITS REPRESENTED HEREBY ARE SUBJECT TO (1) RESTRICTIONS ON TRANSFERABILITY AND RESALE, INCLUDING (A) THOSE SET FORTH IN AN INVESTORS’ RIGHTS AGREEMENT AND (B) CERTAIN RIGHTS OF CO-SALE, AS SET FORTH IN A CO-SALE AGREEMENT, AND (2) VOTING RESTRICTIONS AS SET FORTH IN A VOTING AGREEMENT. SAID AGREEMENTS ARE AMONG THE COMPANY AND THE ORIGINAL HOLDERS OF THESE UNITS, COPIES OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE COMPANY. BY ACCEPTING ANY INTEREST IN SUCH UNITS THE PERSON HOLDING SUCH INTEREST SHALL BE DEEMED TO AGREE TO AND SHALL BECOME BOUND BY ALL THE PROVISIONS OF SAID AGREEMENTS.

3.9 Accredited Investor. The Purchaser is an accredited investor as defined in Rule 501(a) of Regulation D promulgated under the Securities Act.

3.10 No General Solicitation. Neither the Purchaser, nor any of its officers, directors, employees, agents, stockholders or partners has either directly or indirectly, including through a broker or finder, (a) engaged in any general solicitation, or (b) published any advertisement in connection with the offer and sale of the Units.

3.11 Tax Advisors. The Purchaser has reviewed with its own tax advisors the Tax consequences of the Unit Purchase. With respect to such matters, the Purchaser is relying solely on such advisors and not on any statements or representations of the Company or any of its agents, written or oral. The Purchaser understands that it (and not the Company) shall be responsible for its own Tax liability that may arise as a result of the Unit Purchase.

ARTICLE 4

CLOSING MATTERS

The obligations of the Company to issue and sell, and of each Purchaser to purchase, Units at the Closing are subject to the fulfillment or waiver, on or before the Closing, of their respective conditions set forth in Article 6 of the Joint Venture Agreement.

ARTICLE 5

MISCELLANEOUS

5.1 Survival of Representations, Warranties and Covenants. Unless otherwise set forth in this Agreement, the representations, warranties and covenants of the Company and the Purchasers contained in or made pursuant to this Agreement shall survive the execution and delivery of this Agreement and the Closing until the earlier of (a) the three year anniversary of the date of the Closing or (b) the consummation of the transactions to be undertaken pursuant to

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the exercise of the Buy-Out Option. The survival of such representations, warranties and covenants shall in no way be affected by any investigation or Knowledge of the subject matter thereof made by or on behalf of the Purchasers or the Company.

5.2 Indemnification; Sole Remedy; Dispute Resolution. The Company and the Purchasers acknowledge and agree that their respective liabilities and obligations for breaches of the representations, warranties and covenants contained in this Agreement are governed by and subject to the terms and conditions of Article 9 of the Joint Venture Agreement. Further, the parties expressly acknowledge and agree that the remedy for breaches of representations, warranties and covenants under the Joint Venture Agreement are addressed solely in Article 9 of the Joint Venture Agreement, and any incorporation by reference of such representations, warranties and covenants in this Agreement shall not give rise to claims under this Agreement. For the avoidance of doubt, nothing in this Agreement nor any other Transaction Agreement is intended to nor shall be deemed to grant any party more than a single monetary damages remedy or recovery, in any given instance, for any other party’s breach of an individual representation or warranty with respect to any specific given event, fact or circumstance, even though such representation or warranty may be present in more than one Transaction Agreement or claimed by its incorporation by reference to be confirmed in more than one Transaction Agreement. Any dispute arising out of or in connection with this Agreement shall be submitted for resolution in accordance with Article 10 of the Joint Venture Agreement. The parties shall be entitled to injunctive relief or specific performance to the extent provided for in Section 10.4 of the Joint Venture Agreement.

5.3 Successors and Assigns. Except as provided in this Section 5.3, this Agreement shall not be assignable or otherwise transferred, in whole or in part, by any party to any Third Party without the written consent of any other party hereto, provided that this Agreement may without requiring the consent of any other party be assigned, transferred, delegated or sublicensed to (a) an entity that acquires all or substantially all of the business or assets of such party, whether by merger, reorganization, acquisition, asset sale or otherwise, or (b) a Related Entity of such party, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement, the Asset Contribution Agreement and the Joint Venture Agreement. Except as expressly provided in this Section 5.3, any attempted assignment or transfer of this Agreement shall be null and void. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the parties.

5.4 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of Delaware as applied to agreements entered into among Delaware residents to be performed entirely within Delaware, without regard to principles of conflicts of law.

5.5 Counterparts. This Agreement may be executed and delivered by PDF signature and in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

5.6 Titles and Subtitles. The titles and subtitles used in this Agreement are used for convenience only and are not to be considered in construing or interpreting this Agreement. All references in this Agreement to sections, paragraphs and exhibits shall, unless otherwise provided, refer to sections and paragraphs hereof and exhibits attached hereto.

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5.7 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent by electronic mail or otherwise delivered by hand, messenger or courier service addressed:

If to Maxygen or the Company

addressed to:	Maxygen, Inc./Perseid Therapeutics LLC
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: Chief Business Officer
	Telephone: (650) 298-5300
	E-mail: corporatesecretary@maxygen.com
with copy to:	Maxygen, Inc.
	515 Galveston Drive
	Redwood City, California 94063
	USA
	Attention: General Counsel
	Telephone: (650) 298-5300
	E-mail: corporatesecretary@maxygen.com
and a copy to:	Wilson Sonsini Goodrich & Rosati
	Professional Corporation
	650 Page Mill Road
	Palo Alto, CA 94304-1050
	USA
	Attention: Tony Jeffries, Esq.
	Telephone: (650) 493-9300
	E-mail: tjeffries@wsgr.com
If to Bio, addressed to:	Astellas Bio Inc.
	2-3-11, Nihonbashi-Honcho
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Business Development
	Telephone: (813) 3244-2500
	E-mail: masaki.doi@jp.astellas.com

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with a copy to:	Astellas Pharma Inc.
	2-3-11, Nihonbashi-Honcho
	Chuo-ku, Tokyo 103-8411
	Japan
	Attention: Vice President, Legal
	Telephone: (813) 3244-3231
	E-mail: kazunori.okimura@jp.astellas.com
with a copy to:	Morrison & Foerster LLP
	1290 Avenue of the Americas
	New York, NY 10104
	USA
	Attention: Michael O. Braun, Esq.
	Telephone: (212) 468-8000
	E-mail: mbraun@mofo.com

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given (a) if delivered by hand, messenger or courier service, when delivered (or if sent via a nationally-recognized overnight courier service, freight prepaid, specifying next-business-day delivery, two Business Days after deposit with the courier), (b) if sent via registered or certified mail, at the earlier of its receipt or five days after the same has been deposited in a regularly-maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid, or (c) if sent via electronic mail, when directed to the relevant electronic mail address, if sent during normal business hours of the recipient, or if not sent during normal business hours of the recipient, then on the recipient’s next Business Day and in either case later confirmed in writing.

Each Purchaser consents to the delivery of any notice to members given by the Company under the LLCA, the Certificate or the LLC Agreement by (x) electronic mail to the electronic mail address set forth above (or to any other electronic mail address for the Purchaser in the Company’s records), (y) posting on an electronic network together with separate notice to the Purchaser of such specific posting or (z) any other form of electronic transmission (as defined in LLCA §18-302) directed to the Purchaser. This consent may be revoked by a Purchaser by written notice to the Company and may be deemed revoked in the circumstances specified in Section 10.01(d) of the LLC Agreement.

5.8 No Finder’s Fees. Each party represents that it neither is nor will be obligated for any finder’s fee or commission in connection with the Unit Purchase. Each Purchaser agrees to indemnify and to hold harmless the Company from any liability for any commission or compensation in the nature of a finder’s or broker’s fee arising out of the Unit Purchase (and the costs and expenses of defending against such liability or asserted liability) for which such Purchaser or any of its officers, employees, or representatives is responsible. The Company agrees to indemnify and hold harmless each Purchaser from any liability for any commission or compensation in the nature of a finder’s or broker’s fee arising out of the Unit Purchase (and the costs and expenses of defending against such liability or asserted liability) for which the Company or any of its officers, employees or representatives is responsible.

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5.9 Amendments and Waivers. Any term of this Agreement may be amended, terminated or waived only with the written consent of the Company and each Purchaser. Any amendment or waiver effected in accordance with this Section 5.9 shall be binding upon each Purchaser and each transferee of the Units (or the Common Units issuable upon conversion thereof), each future holder of all such securities and the Company.

5.10 Severability. The invalidity or unenforceability of any provision hereof shall in no way affect the validity or enforceability of any other provision.

5.11 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party under this Agreement upon any breach or default of any other party under this Agreement shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring; nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any kind or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party, shall be cumulative and not alternative.

5.12 Entire Agreement. This Agreement (including any exhibits hereto), the Certificate, the LLC Agreement and the other Transaction Agreements constitute the full and entire understanding and agreement between the parties hereto with respect to the subject matter hereof and thereof, and any other written or oral agreement relating to the subject matter hereof and thereof existing between the parties is expressly canceled.

5.13 Interpretation. Unless otherwise indicated herein, with respect to any reference made in this Agreement to a Section (or Article, Subsection, Paragraph, Subparagraph or Clause), Exhibit or Schedule, such reference shall be to a section (or article, subsection, paragraph, subparagraph or clause) of, or an exhibit or schedule to, this Agreement. The table of contents and any article, section, subsection, paragraph or subparagraph headings contained in this Agreement and the recitals at the beginning of this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed, as the context indicates, to be followed by the words “but (is/are) not limited to.” Words used herein, regardless of the number and gender specifically used, shall be deemed and construed to include any other number, singular or plural, and any other gender, masculine, feminine or neuter, as the context indicates is appropriate. Where specific language is used to clarify or illustrate by example a general statement contained herein, such specific language shall not be deemed to modify, limit or restrict the construction of the general statement which is being clarified or illustrated. Unless otherwise specified, any reference to a time or date shall be with reference to the time or date, as the case may be, in Wilmington, Delaware.

[Signature page follows]

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IN WITNESS WHEREOF, the parties have executed this Series A and Series B Preferred Unit Purchase Agreement as of the date first written above.

PERSEID THERAPEUTICS LLC:
By:	/s/    Grant Yonehiro
Name:	Grant Yonehiro
Title:	Chief Executive Officer and President

Signature Page to Unit Purchase Agreement

IN WITNESS WHEREOF, the parties have executed this Series A and Series B Preferred Unit Purchase Agreement as of the date first written above.

MAXYGEN, INC.:
By:	/s/    Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

Signature Page to Unit Purchase Agreement

IN WITNESS WHEREOF, the parties have executed this Series A and Series B Preferred Unit Purchase Agreement as of the date first written above.

ASTELLAS BIO INC.:
By:	/s/    Kazunori Okimura
Name:	Kazunori Okimura
Title:	Secretary

Signature Page to Unit Purchase Agreement

EX-2.1.5

EXHIBIT 2.1.5

PERSEID THERAPEUTICS LLC

INVESTORS’ RIGHTS AGREEMENT

September 18, 2009

TABLE OF CONTENTS

	Page
SECTION 1 DEFINITIONS	1
1.1      Certain Definitions	1
SECTION 2 REGISTRATION RIGHTS	5
2.1      Requested Registration	5
2.2      Company Registration	7
2.3      Registration on Form S-3	9
2.4      Expenses of Registration	10
2.5      Registration Procedures	10
2.6      Indemnification	12
2.7      Information by Holder	14
2.8      Restrictions on Transfer	14
2.9      Rule 144 Reporting	15
2.10    Market Stand-Off Agreement	16
2.11    Delay of Registration	16
2.12    Transfer or Assignment of Registration Rights	16
2.13    Limitations on Subsequent Registration Rights	17
2.14    Termination of Registration Rights	17
SECTION 3 COVENANTS OF THE COMPANY	17
3.1      Basic Financial Information and Inspection Rights	17
3.2      Confidentiality	19
3.3      Termination of Covenants	19
SECTION 4 RIGHT OF FIRST REFUSAL	19
4.1      Right of First Refusal to Investors	19
SECTION 5 COVENANTS OF THE INVESTORS	20
5.1      Buy-Out Option	20
SECTION 6 MISCELLANEOUS	23
6.1      Amendment	23
6.2      Notices	24
6.3      Governing Law	25
6.4      Successors and Assigns	25
6.5      [Reserved]	25
6.6      Entire Agreement	25
6.7      Delays or Omissions	25
6.8      Severability	26
6.9      Titles and Subtitles	26

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TABLE OF CONTENTS

(Continued)

	Page
6.10    Counterparts	26
6.11    Jurisdiction; Venue	26
6.12    Further Assurances	26
6.13    Specific Performance	26
6.14    Termination upon Change of Control	26
6.15    Conflict	27
6.16    Attorneys’ Fees	27
6.17    Aggregation of Company Securities	27
6.18    Jury Trial	27

The registrant agrees to furnish to the Securities and Exchange Commission upon request a copy of any omitted schedule or exhibit.

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PERSEID THERAPEUTICS LLC

INVESTORS’ RIGHTS AGREEMENT

This Investors’ Rights Agreement (this “Agreement”) is dated as of September 18, 2009, and is between Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), and the persons and entities listed on Exhibit A (each, an “Investor” and collectively, the “Investors”). Astellas Pharma Inc. (“Astellas”), for purposes of Sections 5.1(h) and 5.1(i) only, and Astellas US Holding, Inc. (“Astellas US”), for the purposes of Section 5.1(g) only, shall also be parties herein. All capitalized terms used and not defined herein shall have such meanings as set forth in the Master Joint Venture Agreement by and between Maxygen, Inc. (“Maxygen”), Astellas, and Astellas Bio Inc. (“Bio”) dated as of June 30, 2009 (the “Joint Venture Agreement”).

RECITALS

The Investors and the Company are parties to the Series A and Series B Preferred Unit Purchase Agreement of even date herewith (the “Purchase Agreement”), and it is a condition to the closing of the sale of the Series A Preferred Units and Series B Preferred Units to the Investors that the Investors and the Company execute and deliver this Agreement.

The parties therefore agree as follows:

SECTION 1 DEFINITIONS

1.1 Certain Definitions. As used in this Agreement, the following terms shall have the meanings set forth below:

(a) “Buy-Out Option” shall have the meaning set forth in Section 5.1(a).

(b) “Buy-Out Units” shall have the meaning set forth in Section 5.1(a).

(c) “Certificate” shall mean the Company’s Certificate of formation as filed September 8, 2009 and as amended from time to time.

(d) “Commission” shall mean the Securities and Exchange Commission or any other federal agency at the time administering the Securities Act.

(e) “Common Units” shall mean the common units of the Company.

(f) “Company Indemnified Party” shall have the meaning set forth in Section 2.6(b).

(g) “Company Securities” shall mean Units or Registrable Securities.

(h) “Company” shall mean CPC, provided that following the Entity Conversion, “Company” shall mean the Conversion Entity.

(i) “Contributed Assets” shall have the meaning set forth in Section 2.1 of the Asset Contribution Agreement.

(j) “Conversion Entity” shall mean the corporation resulting from the Entity Conversion.

(k) “Conversion Stock” shall mean the Common Stock of the Conversion Entity issued in exchange for the membership interests of CPC upon the Entity Conversion.

(l) “Conversion Units” shall mean the Common Units issued upon conversion of the Preferred Units.

(m) “DGCL” shall mean the General Corporation Law of the State of Delaware.

(n) “DLLCA” shall mean the Limited Liability Company Act of the State of Delaware.

(o) “Entity Conversion” shall mean the conversion of CPC from a limited liability company to a corporation pursuant to Section 9.04 of the LLC Agreement.

(p) “Equity Plan” shall mean the Company’s 2009 Equity Incentive Plan.

(q) “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, or any similar successor federal statute and the rules and regulations thereunder, all as the same shall be in effect from time to time.

(r) “Exercise Price” shall have the meaning set forth in Section 5.1(a).

(s) “Governmental Entity” shall mean any U.S. federal, state or local or any foreign government or any court of competent jurisdiction, administrative or regulatory agency or commission or other governmental authority or agency, domestic or foreign.

(t) “Holder Indemnified Party” shall have the meaning set forth in Section 2.6(a).

(u) “Holder” shall mean any Investor who holds Registrable Securities and any holder of Registrable Securities to whom the registration rights conferred by this Agreement have been duly and validly transferred in accordance with Section 2.12 of this Agreement.

(v) “Indemnified Party” shall have the meaning set forth in Section 2.6(c).

(w) “Indemnifying Party” shall have the meaning set forth in Section 2.6(c).

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(x) “Initial Public Offering” shall mean the closing of the Conversion Entity’s first firm commitment underwritten public offering of its Common Stock registered under the Securities Act.

(y) “Initiating Holders” shall mean any Holder or Holders who in the aggregate hold a majority of the outstanding Registrable Securities.

(z) “Investors” shall have the meaning set forth in the Preamble.

(aa) “Loan Agreement” shall have the meaning set forth in Section 5.1(g).

(bb) “Loan Conditions” shall have the meaning set forth in Section 5.1(g).

(cc) “Loan Option” shall have the meaning set forth in Section 5.1(g).

(dd) “Maximum Loan Amount” shall have the meaning set forth in the Loan Agreement.

(ee) “New Securities” shall have the meaning set forth in Section 4.1(a).

(ff) “Option Closing” shall have the meaning set forth in Section 5.1(d).

(gg) “Option Expiration Date” shall have the meaning set forth in Section 5.1(a).

(hh) “Option Notice” shall have the meaning set forth in Section 5.1(a).

(ii) “Other Products Option” shall mean the Option defined in the Other Products Collaboration Agreement.

(jj) “Preferred Unit” shall mean the Series A Preferred Units and Series B Preferred Units of the Company.

(kk) “Purchase Agreement” shall have the meaning set forth in the Recitals.

(ll) “Qualified Public Offering” shall mean a firm commitment underwritten initial public offering by the Company pursuant to an effective registration statement filed under the Securities Act, covering the offer and sale of the Common Units, provided that the pre-offering valuation of the Company is at least $200,000,000 and the aggregate gross proceeds to the Company are more than $50,000,000.

(mm) “Registrable Securities” shall mean (i) shares of Common Stock issued or issuable pursuant to the conversion of the Units upon the Entity Conversion and (ii) any Common Stock issued as a dividend or other distribution with respect to or in exchange for or in replacement of the shares referenced in (i) above; provided, however, that Registrable Securities shall not include any securities described in clause (i) or (ii) above which have previously been registered or which

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have been sold to the public either pursuant to a registration statement or Rule 144, or which have been sold in a private transaction in which the transferor’s rights under this Agreement are not validly assigned in accordance with this Agreement.

(nn) The terms “register,” “registered” and “registration” shall refer to a registration effected by preparing and filing a registration statement in compliance with the Securities Act and applicable rules and regulations thereunder, and the declaration or ordering of the effectiveness of such registration statement.

(oo) “Registration Expenses” shall mean all expenses incurred in effecting any registration pursuant to this Agreement, which shall be paid in any event by the Company, including, without limitation, all registration and qualification fees, printing expenses, escrow fees, fees and disbursements of counsel for the Company, blue sky fees and expenses, and expenses of any regular or special audits incident to or required by any such registration, but shall not include Selling Expenses and the compensation of regular employees of the Company.

(pp) “Related Entity” means, with respect to any party hereto, (i) any corporation, trust, limited liability company, association or other entity in which such party holds an 80% or greater equity interest, (ii) any parent corporation, trust, limited liability company or association, or other parent entity, of such party or (iii) any liquidating trust or similar entity established for the benefit of such party’s equityholders.

(qq) “Restricted Securities” shall mean any Registrable Securities required to bear the first paragraph of the legend described in Section 2.8(c).

(rr) “Rule 144” shall mean Rule 144 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission.

(ss) “Rule 145” shall mean Rule 145 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission

(tt) “Rule 415” shall mean Rule 415 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission.

(uu) “Securities Act” shall mean the Securities Act of 1933, as amended, or any similar successor federal statute and the rules and regulations thereunder, all as the same shall be in effect from time to time.

(vv) “Securityholder” shall mean a holder of Units or Registrable Securities.

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(ww) “Selling Expenses” shall mean all underwriting discounts, filing fees, selling commissions and stock transfer taxes applicable to the sale of Registrable Securities and fees and disbursements of counsel for any Holder.

(xx) “Series A Preferred Units” shall mean the Series A Preferred Units issued pursuant to the Purchase Agreement.

(yy) “Series B Preferred Units” shall mean the Series B Preferred Units issued pursuant to the Purchase Agreement.

(zz) “Units” shall mean the Series A Preferred Units and Series B Preferred Units.

(aaa) “Transfer” shall have such meaning as set forth in Section 1.1 of the Co-Sale Agreement dated September 18, 2009 by and among the Company and the Investors.

(bbb) “Withdrawn Registration” shall mean a forfeited demand or S-3 registration under Section 2.1 or Section 2.3, respectively, in accordance with the terms and conditions of Section 2.4.

SECTION 2 REGISTRATION RIGHTS

2.1 Requested Registration.

(a) Request for Registration. Subject to the conditions set forth in this Section 2.1, if the Company shall receive from Initiating Holders a written request signed by such Initiating Holders that the Company effect any registration with respect to all or a part of the Registrable Securities (such request shall state the number of Registrable Securities to be disposed of and the intended methods of disposition of such securities by such Initiating Holders), the Company will:

(i) within ten (10) days give written notice of the proposed registration to all other Holders, who shall then have the right to request inclusion in such registration of all or a part of their Registrable Securities; and

(ii) as soon as practicable, file and use its commercially reasonable efforts to effect such registration (including, without limitation, filing post-effective amendments, appropriate qualifications under applicable blue sky or other state securities laws, and appropriate compliance with the Securities Act) and to permit or facilitate the sale and distribution of all or such portion of such Registrable Securities as are specified in such request, together with all or such portion of the Registrable Securities of any Holder or Holders joining in such request as are specified in a written request received by the Company within twenty (20) days after such written notice from the Company is mailed or delivered.

(b) Limitations on Requested Registration. The Company shall not be obligated to effect, or to take any action to effect, any such registration pursuant to this Section 2.1:

(i) Prior to the earlier of (A) the later to occur of the Entity Conversion and three (3) year anniversary of the date of this Agreement or (B) six (6) months following the Company’s Initial Public Offering;

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(ii) In any particular jurisdiction in which the Company would be required to execute a general consent to service of process in effecting such registration, qualification, or compliance, unless the Company is already subject to service in such jurisdiction and except as may be required by the Securities Act;

(iii) After the Company has initiated two (2) such registrations pursuant to this Section 2.1 (counting for these purposes only (x) registrations which have been declared or ordered effective and pursuant to which securities have been sold, and (y) Withdrawn Registrations);

(iv) During the period starting with the date sixty (60) days prior to the Company’s good faith estimate of the date of filing of, and ending on a date one hundred eighty (180) days after the effective date of, a Company-initiated registration (or ending on the subsequent date on which all market stand-off agreements applicable to the offering have terminated); provided that the Company is actively employing in good faith commercially reasonable efforts to cause such registration statement to become effective;

(v) If the Initiating Holders propose to dispose of Registrable Securities that may be registered on Form S-3 pursuant to a request made under Section 2.3;

(vi) If the Initiating Holders do not request that such offering be firmly underwritten by underwriters selected by the Initiating Holders (subject to the consent of the Company); or

(vii) If the Company and the Initiating Holders are unable to obtain the commitment of the underwriter described in clause (b)(iv) above to firmly underwrite the offer.

(c) Deferral. If (i) in the good faith judgment of the board of directors of the Company, the filing of a registration statement covering the Registrable Securities would be detrimental to the Company and the board of directors of the Company concludes, as a result, that it is in the best interests of the Company to defer the filing of such registration statement at such time, and (ii) the Company shall furnish to such Holders a certificate signed by the President of the Company stating that in the good faith judgment of the board of directors of the Company, it would be detrimental to the Company for such registration statement to be filed in the near future and that it is, therefore, in the best interests of the Company to defer the filing of such registration statement, then (in addition to the limitations set forth in Section 2.1(b)(iv) above) the Company shall have the right to defer such filing for a period of not more than ninety (90) days after receipt of the request of the Initiating Holders, and, provided further, that the Company shall not defer its obligation in this manner more than twice in any twelve-month period.

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(d) Other Securities. The registration statement filed pursuant to the request of the Initiating Holders may include securities of the Company being sold for the account of the Company.

(e) Underwriting. The right of any Holder to include all or any portion of its Registrable Securities in a registration pursuant to this Section 2.1 shall be conditioned upon such Holder’s participation in an underwriting and the inclusion of such Holder’s Registrable Securities to the extent provided herein. The Company shall (together with all Holders proposing to distribute their securities through such underwriting) enter into an underwriting agreement in customary form with the representative of the underwriter or underwriters selected for such underwriting by the Company, which underwriters are reasonably acceptable to a majority in interest of the Initiating Holders.

Notwithstanding any other provision of this Section 2.1, if the underwriters advise the Initiating Holders in writing that marketing factors require a limitation on the number of Registrable Securities to be underwritten, the number of Registrable Securities that may be so included shall be allocated among all Holders requesting to include Registrable Securities in such registration statement based on the pro rata percentage of Registrable Securities that each such Holder has requested be included in such registration statement. In no event shall the number of Registrable Securities underwritten in such registration be limited unless and until all Registrable Securities held by persons other than Holders, including the Company, are completely excluded from such offering.

If a person who has requested inclusion in such registration as provided above does not agree to the terms of any such underwriting, such person shall be excluded therefrom by written notice from the Company, the underwriter or the Initiating Holders. The securities so excluded shall also be withdrawn from registration. Any Registrable Securities or other securities excluded or withdrawn from such underwriting shall also be withdrawn from such registration. If Registrable Securities are so withdrawn from the registration and if the number of Registrable Securities to be included in such registration was previously reduced as a result of marketing factors pursuant to this Section 2.1(e), then the Company shall offer to all Holders who have retained rights to include securities in the registration the right to include additional Registrable Securities in the registration in an aggregate amount equal to the number of Registrable Securities so withdrawn, with such Registrable Securities to be allocated among such Holders requesting additional inclusion, as set forth above.

2.2 Company Registration.

(a) Company Registration. If the Company shall determine to register any of its securities either for its own account or the account of a security holder or holders, other than a registration pursuant to Section 2.1 or 2.3, a registration relating solely to employee benefit plans, a registration relating to the offer and sale of debt securities, a registration relating to a corporate reorganization or other Rule 145 transaction, or a registration on any registration form that does not permit secondary sales, the Company will:

(i) promptly give written notice of the proposed registration to all Holders; and

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(ii) use its commercially reasonable efforts to include in such registration (and any related qualification under blue sky laws or other compliance), except as set forth in Section 2.2(b) below, and in any underwriting involved therein, all of such Registrable Securities as are specified in a written request or requests made by any Holder or Holders received by the Company within ten (10) days after such written notice from the Company is mailed or delivered. Such written request may specify all or a part of a Holder’s Registrable Securities.

(b) Underwriting. If the registration of which the Company gives notice is for a registered public offering involving an underwriting, the Company shall so advise the Holders as a part of the written notice given pursuant to Section 2.2(a)(i). In such event, the right of any Holder to registration pursuant to this Section 2.2 shall be conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable Securities in the underwriting to the extent provided herein. All Holders proposing to distribute their securities through such underwriting shall (together with the Company and the other holders of securities of the Company with registration rights to participate therein distributing their securities through such underwriting) enter into an underwriting agreement in customary form with the representative of the underwriter or underwriters selected by the Company.

Notwithstanding any other provision of this Section 2.2, if the underwriters advise the Company in writing that marketing factors require a limitation on the number of securities to be underwritten, the underwriters may (subject to the limitations set forth below) limit the number of Registrable Securities to be included in the registration and underwriting. The Company shall so advise all holders of securities requesting registration, and the number of securities that are entitled to be included in the registration and underwriting shall be allocated, as follows: (i) first, to the Company for securities being sold for its own account, and (ii) second, to the Holders requesting to include Registrable Securities in such registration statement based on their pro rata share of Registrable Securities to be included in the registration, assuming conversion. Notwithstanding the foregoing, no such reduction shall reduce the value of the Registrable Securities of the Holders included in such registration below twenty-five percent (25%) of the total value of securities included in such registration, unless such offering is a Qualified Public Offering and such registration does not include securities of any other selling stockholders (excluding Registrable Securities registered for the account of the Company), in which event any or all of the Registrable Securities of the Holders may be excluded.

If a person who has requested inclusion in such registration as provided above does not agree to the terms of any such underwriting, such person shall also be excluded therefrom by written notice from the Company or the underwriter. The Registrable Securities or other securities so excluded shall also be withdrawn from such registration. Any Registrable Securities or other securities excluded or withdrawn from such underwriting shall be withdrawn from such registration. If Registrable Securities are so withdrawn from the registration and if the number of Registrable Securities to be included in such registration was previously reduced as a result of marketing factors

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pursuant to Section 2.2(b), the Company shall then offer to all persons who have retained the right to include securities in the registration the right to include additional securities in the registration in an aggregate amount equal to the number of Registrable Securities so withdrawn, with such Registrable Securities to be allocated among the persons requesting additional inclusion, in the manner set forth above.

(c) Right to Terminate Registration. The Company shall have the right to terminate or withdraw any registration initiated by it under this Section 2.2 prior to the effectiveness of such registration whether or not any Holder has elected to include securities in such registration.

2.3 Registration on Form S-3.

(a) Request for Form S-3 Registration. After its initial public offering, the Company shall use its commercially reasonable efforts to qualify for registration on Form S-3 or any comparable or successor form or forms. After the Company has qualified for the use of Form S-3, in addition to the rights contained in the foregoing provisions of this SECTION 2 and subject to the conditions set forth in this Section 2.3, if the Company shall receive from a Holder or Holders of Registrable Securities a written request that the Company effect any registration on Form S-3 or any similar short form registration statement with respect to all or part of such Registrable Securities (such request shall state the number of Registrable Securities to be disposed of and the intended methods of disposition of such Registrable Securities by such Holder or Holders), the Company will take all such action with respect to such Registrable Securities as required by Section 2.1(a)(i) and 2.1(a)(ii).

(b) Limitations on Form S-3 Registration. The Company shall not be obligated to effect, or take any action to effect, any such registration pursuant to this Section 2.3:

(i) In the circumstances described in either Sections 2.1(b)(i), 2.1(b)(ii) or 2.1(b)(iv); or

(ii) After the Company has initiated two (2) such registrations pursuant to this Section 2.3 (counting for these purposes only (x) registrations which have been declared or ordered effective and pursuant to which securities have been sold, and (y) Withdrawn Registrations).

(c) Deferral. The provisions of Section 2.1(c) shall apply to any registration pursuant to this Section 2.3.

(d) Underwriting. If the Holders of Registrable Securities requesting registration under this Section 2.3 intend to distribute the Registrable Securities covered by their request by means of an underwriting, the provisions of Section 2.1(d) shall apply to such registration. Notwithstanding anything contained herein to the contrary, registrations effected pursuant to this Section 2.3 shall not be counted as requests for registration or registrations effected pursuant to Section 2.1.

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2.4 Expenses of Registration. All Registration Expenses incurred in connection with registrations pursuant to Sections 2.1, 2.2 and 2.3 shall be borne by the Company; provided, however, that the Company shall not be required to pay for any expenses of any registration proceeding begun pursuant to Sections 2.1 and 2.3 if the registration request is subsequently withdrawn at the request of the Holders of a majority of the Registrable Securities to be registered or because a sufficient number of Holders shall have withdrawn so that the minimum offering conditions set forth in Sections 2.1 are no longer satisfied (in which case all participating Holders shall bear such expenses pro rata among each other based on the number of Registrable Securities requested to be so registered), unless the Holders of a majority of the Registrable Securities agree to forfeit their right to one demand registration pursuant to Section 2.1 in the event that the withdrawn registration was initiated pursuant to Section 2.1 or Section 2.3 in the event that the withdrawn registration was initiated pursuant to Section 2.3; provided, however, in the event that a withdrawal by the Holders is based upon material adverse information relating to the Company that is different from the information known or available (upon request from the Company or otherwise) to the Holders requesting registration at the time of their request for registration under Section 2.1 or Section 2.3, as the case may be, such registration shall not be treated as a counted registration for purposes of Section 2.1 or Section 2.3, as the case may be, even though the Holders do not bear the Registration Expenses for such registration. All Selling Expenses relating to securities registered on behalf of the Holders shall be borne by the holders of securities included in such registration pro rata among each other on the basis of the number of Registrable Securities so registered.

2.5 Registration Procedures. In the case of each registration effected by the Company pursuant to this SECTION 2, the Company will keep each Holder advised in writing as to the initiation of each registration and as to the completion thereof. At its expense, the Company will use its commercially reasonable efforts to:

(a) Keep such registration effective for a period ending on the earlier of the date which is sixty (60) days from the effective date of the registration statement or such time as the Holder or Holders have completed the distribution described in the registration statement relating thereto;

(b) Prepare and file with the Commission such amendments and supplements to such registration statement and the prospectus used in connection with such registration statement as may be necessary to comply with the provisions of the Securities Act with respect to the disposition of all securities covered by such registration statement for the period set forth in subsection (a) above;

(c) Furnish such number of prospectuses, including any preliminary prospectuses, and other documents incident thereto, including any amendment of or supplement to the prospectus, as a Holder from time to time may reasonably request;

(d) Use its reasonable best efforts to register and qualify the securities covered by such registration statement under such other securities or Blue Sky laws of such jurisdiction as shall be reasonably requested by the Holders; provided, that the Company shall not be required in connection therewith or as a condition thereto to qualify to do business or to file a general consent to service of process in any such states or jurisdictions;

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(e) Notify each seller of Registrable Securities covered by such registration statement at any time when a prospectus relating thereto is required to be delivered under the Securities Act of the happening of any event as a result of which the prospectus included in such registration statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein not misleading or incomplete in light of the circumstances then existing, and following such notification promptly prepare and furnish to such seller a reasonable number of copies of a supplement to or an amendment of such prospectus as may be necessary so that, as thereafter delivered to the purchasers of such Registrable Securities, such prospectus shall not include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading or incomplete in light of the circumstances then existing;

(f) If (i) a registration made pursuant to a registration statement filed under Rule 415 is required to be kept effective in accordance with this Agreement after the third anniversary of the initial effective date of the shelf registration statement and (ii) the registration rights of the applicable Holders have not terminated, file a new registration statement with respect to any unsold Registrable Securities subject to the original request for registration prior to the end of the three (3) year period after the initial effective date of the shelf registration statement, and keep such registration statement effective in accordance with the requirements otherwise applicable under this Agreement;

(g) Use its commercially reasonable efforts to furnish, on the date that such Registrable Securities are delivered to the underwriters for sale, if such securities are being sold through underwriters, (i) an opinion, dated as of such date, of the counsel representing the Company for the purposes of such registration, in form and substance as is customarily given to underwriters in an underwritten public offering, addressed to the underwriters, if any, and reasonably satisfactory to a majority in interest of the Holders requesting registration of Registrable Securities and (ii) a “comfort” letter dated as of such date, from the independent certified public accountants of the Company, in form and substance as is customarily given by independent certified public accountants to underwriters in an underwritten public offering, addressed to the underwriters;

(h) Provide a transfer agent and registrar for all Registrable Securities registered pursuant to such registration statement and a CUSIP number for all such Registrable Securities, in each case not later than the effective date of such registration;

(i) Otherwise use its commercially reasonable efforts to comply with all applicable rules and regulations of the Commission, and make available to its security holders, as soon as reasonably practicable, an earnings statement covering the period of at least twelve (12) months, but not more than eighteen (18) months, beginning with the first month after the effective date of the Registration Statement, which earnings statement shall satisfy the provisions of Section 11(a) of the Securities Act;

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(j) Cause all such Registrable Securities registered pursuant hereunder to be listed on each securities exchange on which similar securities issued by the Company are then listed;

(k) Notify each Holder, promptly after the Company receives notice thereof, of the time when such registration statement has been declared effective or a supplement to any prospectus forming a part of such registration statement has been filed; and

(l) In connection with any underwritten offering pursuant to a registration statement filed pursuant to Section 2.1, enter into an underwriting agreement in form reasonably necessary to effect the offer and sale of Registrable Securities, provided such underwriting agreement contains reasonable and customary provisions, and provided further, that each Holder participating in such underwriting shall also enter into and perform its obligations under such an agreement.

2.6 Indemnification.

(a) To the extent permitted by law, the Company will indemnify and hold harmless each Holder, each of its officers, directors and partners, legal counsel and accountants and each person controlling such Holder within the meaning of Section 15 of the Securities Act, with respect to which registration, qualification or compliance has been effected pursuant to this SECTION 2, and each underwriter, if any, and each person who controls within the meaning of Section 15 of the Securities Act any underwriter (each, a “Holder Indemnified Party”), against all expenses, claims, losses, damages and liabilities (or actions, proceedings or settlements in respect thereof) arising out of or based on: (i) any untrue statement (or alleged untrue statement) of a material fact contained or incorporated by reference in any registration statement, any prospectus included in the registration statement, any issuer free writing prospectus (as defined in Rule 433 of the Securities Act), any issuer information (as defined in Rule 433 of the Securities Act) filed or required to be filed pursuant to Rule 433(d) under the Securities Act or any other document incident to any such registration, qualification or compliance prepared by or on behalf of the Company or used or referred to by the Company, (ii) any omission (or alleged omission) to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, or (iii) any violation (or alleged violation) by the Company of the Securities Act, any state securities laws or any rule or regulation thereunder applicable to the Company and relating to action or inaction required of the Company in connection with any offering covered by such registration, qualification or compliance, and the Company will reimburse each such Holder Indemnified Party, for any legal and any other expenses reasonably incurred in connection with investigating and defending or settling any such claim, loss, damage, liability or action; provided that the Company will not be liable in any such case to the extent that any such claim, loss, damage, liability, or action arises out of or is based on any untrue statement or omission that is based on and conforms with written information furnished to the Company and stated to be specifically for use in any registration statement by such Holder Indemnified Party; and provided, further that, the indemnity agreement contained in this Section 2.6(a) shall not apply to amounts paid in settlement of any such loss, claim, damage, liability or action if such settlement is effected without the consent of the Company (which consent shall not be unreasonably withheld).

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(b) To the extent permitted by law, each Holder, severally and not jointly, will, if Registrable Securities held by such Holder are included in the securities as to which such registration, qualification or compliance is being effected, indemnify and hold harmless the Company, each of its directors, officers, partners, legal counsel and accountants and each underwriter, if any, of the Company’s securities covered by such a registration statement, each person who controls such underwriter within the meaning of Section 15 of the Securities Act, each other such Holder, and each of their officers, directors and partners, and each person controlling each other such Holder (each, a “Company Indemnified Party”), against all claims, losses, damages and liabilities (or actions in respect thereof) arising out of or based on: (i) any untrue statement (or alleged untrue statement) of a material fact contained or incorporated by reference in any prospectus, offering circular or other document (including any related registration statement, notification, or the like) incident to any such registration, qualification or compliance, or (ii) any omission (or alleged omission) to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse the Company Indemnified Party for any legal or any other expenses reasonably incurred in connection with investigating or defending any such claim, loss, damage, liability or action, in each case to the extent, but only to the extent, that such untrue statement (or alleged untrue statement) or omission (or alleged omission) made in such registration statement, prospectus, offering circular or other document is based on and conforms with written information provided by such Holder and stated to be specifically for use therein; provided, however, that the obligations of such Holder hereunder shall not apply to amounts paid in settlement of any such claims, losses, damages or liabilities (or actions in respect thereof) if such settlement is effected without the consent of such Holder (which consent shall not be unreasonably withheld); and provided that in no event shall any indemnity under this Section 2.6 exceed the net proceeds from the offering received by such Holder, except in the case of fraud or willful misconduct by such Holder.

(c) Any Holder Indemnified Party or Company Indemnified Party entitled to indemnification under this Section 2.6 (each, an “Indemnified Party”) shall give notice to the party required to provide indemnification (the “Indemnifying Party”) promptly after such Indemnified Party has actual knowledge of any claim as to which indemnity may be sought, and shall permit the Indemnifying Party to assume the defense of such claim or any litigation resulting therefrom; provided that counsel for the Indemnifying Party, who shall conduct the defense of such claim or any litigation resulting therefrom, shall be approved by the Indemnified Party (whose approval shall not be unreasonably withheld), and the Indemnified Party may participate in such defense at such party’s expense; and provided further that the failure of any Indemnified Party to give notice as provided herein shall not relieve the Indemnifying Party of its obligations under this Section 2.6, to the extent such failure is not materially prejudicial. No Indemnifying Party, in the defense of any such claim or litigation, shall, except with the consent of each Indemnified Party, consent to entry of any judgment or enter into any settlement that does not include as an unconditional term thereof the giving by the claimant or plaintiff to such Indemnified Party of a release from all liability in respect to such claim or litigation. Each Indemnified Party shall furnish such information regarding itself or the claim in question as an Indemnifying Party may reasonably request in writing and as shall be reasonably required in connection with defense of such claim and litigation resulting therefrom.

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(d) If the indemnification provided for in this Section 2.6 is held by a court of competent jurisdiction to be unavailable to an Indemnified Party with respect to any loss, liability, claim, damage, or expense referred to herein, then the Indemnifying Party, in lieu of indemnifying such Indemnified Party hereunder, shall contribute to the amount paid or payable by such Indemnified Party as a result of such loss, liability, claim, damage, or expense in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party on the one hand and of the Indemnified Party on the other in connection with the statements or omissions that resulted in such loss, liability, claim, damage, or expense as well as any other relevant equitable considerations. The relative fault of the Indemnifying Party and of the Indemnified Party shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission to state a material fact relates to information supplied by the Indemnifying Party or by the Indemnified Party and the parties’ relative intent, knowledge, access to information, and opportunity to correct or prevent such statement or omission. No person or entity will be required under this Section 2.6(d) to contribute any amount in excess of the net proceeds from the offering received by such person or entity, except in the case of fraud or willful misconduct by such person or entity. No person or entity guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) will be entitled to contribution from any person or entity who was not guilty of such fraudulent misrepresentation.

(e) Notwithstanding the foregoing, to the extent that the provisions on indemnification and contribution contained in the underwriting agreement entered into in connection with the underwritten public offering are in conflict with the foregoing provisions, the provisions in the underwriting agreement shall control.

2.7 Information by Holder. Each Holder of Registrable Securities shall furnish to the Company such information regarding such Holder and the distribution proposed by such Holder as the Company may reasonably request in writing and as shall be reasonably required in connection with any registration, qualification, or compliance referred to in this SECTION 2.

2.8 Restrictions on Transfer.

(a) The holder of each certificate representing Company Securities by acceptance thereof agrees to comply in all respects with the provisions of this Section 2.8. Each Securityholder agrees not to make any sale, assignment, transfer, pledge or other disposition of all or any portion of such Company Securities, or any beneficial interest therein, unless and until the transferee thereof has agreed in writing for the benefit of the Company to take and hold such Company Securities subject to, and to be bound by, the terms and conditions set forth in this Agreement, including, without limitation, this Section 2.8 and Section 2.10, and:

(i) There is then in effect a registration statement under the Securities Act covering such proposed disposition and the disposition is made in accordance with the registration statement; or

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(ii) The Securityholder shall have given prior written notice to the Company of the Securityholder’s intention to make such disposition and shall have furnished the Company with a detailed description of the manner and circumstances of the proposed disposition, and, if requested by the Company, the Securityholder shall have furnished the Company with evidence reasonably satisfactory to the Company that such disposition will not require registration of such Company Securities under the Securities Act, including, if requested by the Company, an opinion of counsel reasonably satisfactory to the Company, whereupon the holder of such Company Securities shall be entitled to transfer such Company Securities in accordance with the terms of the notice delivered by the Securityholder to the Company. It is agreed that the Company will not require opinions of counsel for transactions made pursuant to Rule 144 except in unusual circumstances.

(b) Notwithstanding the provisions of Section 2.8(a), no such registration statement or opinion of counsel shall be necessary for (i) a transfer not involving a change in beneficial ownership, (ii) transactions involving the distribution without consideration of Company Securities by any Securityholder to (x) a Related Entity of the Securityholder,or (y) any of the Securityholder’s partners, members or other equity owners, or retired partners, retired members or other equity owners, or to the estate of any of the Securityholder’s partners, members or other equity owners or retired partners, retired members or other equity owners, or (iii) a transfer pursuant to the exercise of the Buy-Out Option; provided, in each case, that the Securityholder shall give written notice to the Company of the Securityholder’s intention to effect such disposition and shall have furnished the Company with a detailed description of the manner and circumstances of the proposed disposition.

(c) Each certificate representing Company Securities shall (unless otherwise permitted by the provisions of this Agreement) be stamped or otherwise imprinted with a legend substantially similar to the legend set forth in Section 3.8 of the Purchase Agreement. The Securityholders consent to the Company making a notation on its records and giving instructions to any transfer agent of the Company Securities in order to implement the restrictions on transfer established in this Section 2.8.

(d) The first paragraph of the legend referring to federal and state securities laws set forth in Section 3.8 of the Purchase Agreement and the stock transfer instructions and record notations with respect to the Company Securities shall be removed and the Company shall issue a certificate without such paragraph to the Securityholder if (i) those securities are registered under the Securities Act, or (ii) the Holder provides the Company with an opinion of counsel reasonably acceptable to the Company to the effect that a sale or transfer of those securities may be made without registration or qualification.

2.9 Rule 144 Reporting. With a view to making available the benefits of certain rules and regulations of the Commission that may permit the sale of the Restricted Securities to the public without registration, the Company agrees to use its commercially reasonable efforts to:

(a) Make and keep adequate current public information with respect to the Company available in accordance with Rule 144 under the Securities Act, at all times from and after ninety (90) days following the effective date of the first registration under the Securities Act filed by the Company for an offering of its securities to the general public;

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(b) File with the Commission in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act at any time after it has become subject to such reporting requirements; and

(c) So long as a Holder owns any Restricted Securities, furnish to the Holder forthwith upon written request a written statement by the Company as to its compliance with the reporting requirements of Rule 144 (at any time from and after ninety (90) days following the effective date of the first registration statement filed by the Company for an offering of its securities to the general public), and of the Securities Act and the Exchange Act (at any time after it has become subject to such reporting requirements), a copy of the most recent annual or quarterly report of the Company, and such other reports and documents so filed as a Holder may reasonably request in availing itself of any rule or regulation of the Commission allowing a Holder to sell any such securities without registration.

2.10 Market Stand-Off Agreement. No Holder shall sell or otherwise transfer, make any short sale of, grant any option for the purchase of, or enter into any hedging or similar transaction with the same economic effect as a sale, of any Registrable Securities (or other securities) of the Company held by such Holder (other than those included in the registration) during the one hundred eighty (180) day period following the effective date of the registration statement for the Company’s Initial Public Offering filed under the Securities Act (or such other period as may be requested by the Company or an underwriter to accommodate regulatory restrictions on (i) the publication or other distribution of research reports and (ii) analyst recommendations and opinions, including, but not limited to, the restrictions contained in NASD Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto). The obligations described in this Section 2.10 shall not apply to a registration relating solely to employee benefit plans on Form S-l or Form S-8 or similar forms that may be promulgated in the future, or a registration relating solely to a transaction on Form S-4 or similar forms that may be promulgated in the future. The Company may impose stop-transfer instructions and may stamp each such certificate with the second legend set forth in Section 2.8(c) with respect to the Company Securities (or other securities) subject to the foregoing restriction until the end of such one hundred eighty (180) day (or other) period. Each Holder agrees to execute a market standoff agreement with said underwriters in customary form consistent with the provisions of this Section 2.10.

2.11 Delay of Registration. No Holder shall have any right to take any action to restrain, enjoin, or otherwise delay any registration as the result of any controversy that might arise with respect to the interpretation or implementation of this SECTION 2.

2.12 Transfer or Assignment of Registration Rights. The rights to cause the Company to register securities granted to a Securityholder by the Company under this SECTION 2 may be

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transferred or assigned by a Securityholder only to a transferee or assignee of not less than 5,000,000 Company Securities (as presently constituted and subject to subsequent adjustments for stock splits, stock dividends, reverse stock splits, and the like); provided that (i) such transfer or assignment of Company Securities is effected in accordance with the terms of Section 2.8, the Co-Sale Agreement and applicable securities laws, (ii) the Company is given written notice prior to said transfer or assignment, stating the name and address of the transferee or assignee and identifying the securities with respect to which such registration rights are intended to be transferred or assigned and (iii) the transferee or assignee of such rights assumes in writing the obligations of such Securityholder under this Agreement, including without limitation the obligations set forth in Section 2.10.

2.13 Limitations on Subsequent Registration Rights. The Company shall not, without the prior written consent of each Investor who holds not less than 5,000,000 Company Securities, or in the event that no Investor holds at least 5,000,000 Company Securities, Securityholders holding a majority of the Company Securities, (i) prior to the Option Expiration Date, enter into any agreement with any holder or prospective holder of any securities of the Company giving such holder or prospective holder any registration rights the terms of which are pari passu with or senior to the registration rights granted to the Securityholders hereunder or (ii) on or after the Option Expiration Date (as defined below), enter into any agreement with any holder or prospective holder of any securities of the Company giving such holder or prospective holder any registration rights the terms of which are senior to the registration rights granted to the Securityholders hereunder (however, for the avoidance of doubt, on or following the Option Expiration Date, the Company may give any such holder or prospective holder registration rights which are pari passu with the registration rights granted to the Securityholders hereunder without being required to obtain the prior consent of any Investor pursuant to this Section 2.13, including by making any such holder or prospective holder a party to this Agreement in accordance with Section 6.1).

2.14 Termination of Registration Rights. The right of any Holder to request registration or inclusion in any registration pursuant to Sections 2.1, 2.2 or 2.3 shall terminate on the earlier of (i) such date, on or after the closing of the Company’s first registered public offering of Common Stock, on which all Registrable Securities held or entitled to be held upon conversion by such Holder may immediately be sold under Rule 144 during any ninety (90) day period, and (ii) three (3) years after the closing of the Company’s Initial Public Offering.

SECTION 3 COVENANTS OF THE COMPANY

The Company hereby covenants and agrees, as follows:

3.1 Basic Financial Information and Inspection Rights.

(a) Basic Financial Information. The Company will furnish the following reports to each Securityholder who owns at least 5,000,000 Company Securities (as presently constituted and subject to subsequent adjustments for stock splits, stock dividends, reverse stock splits, and the like); provided, however, that no Securityholder shall by reason of this Section 3.1 have access to any trade secrets or classified information of the Company:

(i) As soon as practicable after the end of each fiscal year of the Company, and in any event within one hundred twenty (120) days after the end of each fiscal year of the Company, an audited consolidated balance sheet of the Company and its subsidiaries, if any, as at the end of such fiscal year, and audited consolidated statements of income and cash flows of the Company and its subsidiaries, if any, for such year, prepared in accordance with U.S. generally accepted accounting principles consistently applied, accompanied by an unqualified report of independent certified public accountants regarding such balance sheet and statements selected by the Company, provided, however, that in lieu of the balance sheet and statements of income and cash flows and a report of independent certified public accountants required to be furnished under this Section 3.1(a)(i), the Company may furnish the audited consolidated financial statements and accompanying report of independent certified public accountants of Maxygen, which audited consolidated financial statements and report of independent certified public accountants shall include or cover, as the case may be, the financial results of the Company.

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(ii) As soon as practicable after the end of the first, second and third quarterly accounting periods in each fiscal year of the Company, and in any event within forty-five (45) days after the end of the first, second, and third quarterly accounting periods in each fiscal year of the Company, an unaudited consolidated balance sheet of the Company and its subsidiaries, if any, as of the end of each such quarterly period, and unaudited consolidated statements of income and cash flows of the Company and its subsidiaries, if any, for such period, prepared in accordance with U.S. generally accepted accounting principles consistently applied, subject to changes resulting from normal year-end audit adjustments, and certified by the Chief Financial Officer of the Company.

(iii) As soon as practicable after the end of each calendar month, and in any event within thirty (30) days after the end of each calendar month, an unaudited consolidated balance sheet of the Company and its subsidiaries, if any, as of the end of each such monthly period, and unaudited consolidated statements of income and cash flows of the Company and its subsidiaries, if any, for such period, prepared in accordance with U.S. generally accepted accounting principles consistently applied, subject to changes resulting from normal year-end audit adjustments, and certified by the Chief Financial Officer of the Company.

(iv) At least thirty (30) days prior to the beginning of each fiscal year an annual business plan, including a budget, for such fiscal year.

(b) Inspection Rights. The Company will afford to each Investor and such Investor’s accountants and counsel, reasonable access during normal business hours to all of the Company’s respective properties, books and records to the extent permitted by applicable law. Each Investor shall have such other access to management and information as is necessary for it to comply with applicable laws and regulations and reporting obligations. The Company shall not be required to disclose details of contracts with, work performed for, or trade secrets of specific customers and other business partners where to do so would violate confidentiality obligations to those parties; provided that the Company will use its commercially reasonable efforts to provide exceptions in all confidentiality agreements to permit such disclosure to the Investors subject to the Investors entering

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into such reasonable confidentiality and non-use agreements with respect to such information as the Company or such other parties may request. Such Investors may exercise their rights under this Section 3.1(b) only for purposes reasonably related to their interests under this Agreement and other Transaction Agreements. The rights granted pursuant to this Section 3.1(b) may not be assigned or otherwise conveyed by such Investors or by any subsequent transferee of any such rights without the prior written consent of the Company.

3.2 Confidentiality. Any information disclosed pursuant to this SECTION 3 shall be Confidential Information and subject to the requirements of Section 8.7 of the Joint Venture Agreement. Notwithstanding the foregoing, no Investor shall by reason of any Transaction Agreement (including, without limitation, this Agreement) have access to any trade secrets or classified information of the Company. The Company shall not be required to comply with any information rights contained in any Transaction Agreement (including, without limitation, this Agreement) in respect of any Investor whom the Company reasonably determines to be a competitor or an officer, employee, director or holder of more than a ten percent (10%) ownership interest of a competitor of the Company. The Investors agree that, in the event that any person other than an Investor becomes party to this Agreement, the Investors will take all appropriate actions to require such person to confidentiality requirements substantially consistent with those set forth in this Section 3.2 and Section 8.7 of the Joint Venture Agreement.

3.3 Termination of Covenants. The covenants set forth in this SECTION 3 shall terminate and be of no further force and effect after the closing of the Company’s Initial Public Offering.

SECTION 4 RIGHT OF FIRST REFUSAL

4.1 Right of First Refusal to Investors. The Company hereby grants to each Investor during such time as such Investor owns at least 5,000,000 Company Securities and/or Conversion Units the right of first refusal to purchase its pro rata share of New Securities (as defined in this Section 4.1(a)) which the Company may, from time to time, propose to sell and issue after the date of this Agreement. An Investor’s pro rata share, for purposes of this right of first refusal, is equal to the ratio of (a) the number of Common Units (or, following the Entity Conversion, Conversion Stock) owned by such Investor immediately prior to the issuance of New Securities (assuming full conversion of the Units and full conversion or exercise of all outstanding convertible securities, rights, options and warrants held by said Investor) to (b) the total number of Common Units (or, following the Entity Conversion, Conversion Stock) outstanding immediately prior to the issuance of New Securities (assuming full conversion of the Units and full conversion or exercise of all outstanding convertible securities, rights, options and warrants). For the avoidance of doubt, the right of first refusal provided for in this Section 4.1 shall survive and be unaffected by the occurrence of the Option Expiration Date.

(a) “New Securities” shall mean any security (including Common Units and/or Preferred Units) of the Company whether now authorized or not, and rights, convertible securities, options or warrants to purchase such securities including any capital stock, or Units and securities of

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any type whatsoever that are, or may become, exercisable or convertible into capital stock; provided that the term “New Securities” does not include any security of the Company that is excluded from the definition of “Additional Common Units” in Section 4.03(d)(i) of the LLC Agreement (or, after the Entity Conversion, any Conversion Stock corresponding to the securities excluded from the definition of “Additional Common Units”) as well as any Common Units (including Profits Interest Units, as defined in the LLC Agreement) or Conversion Stock and options, warrants or other rights to purchase Common Units or Conversion Stock issued or issuable to officers, employees, directors, consultants, placement agents or other service providers of the Company (or any subsidiary) pursuant to grants, restricted unit purchase agreements, option plans, purchase plans, agreements or other employee stock incentive programs or similar arrangements approved by the Company’s board of managers to the extent not so excluded by Section 4.03(d)(i) of the LLC Agreement.

(b) In the event the Company proposes to undertake an issuance of New Securities, it shall give each Investor written notice of its intention, describing the type of New Securities, their price and the general terms upon which the Company proposes to issue the same. Each Investor shall have fifteen (15) days after any such notice is mailed or delivered (the “Election Period”) to agree to purchase such Holder’s pro rata share of such New Securities for the price and upon the terms specified in the notice by giving written notice to the Company, in substantially the form attached as Exhibit B, and stating therein the quantity of New Securities to be purchased.

(c) In the event the Investors fail to exercise fully the right of first refusal within the Election Period, the Company shall have ninety (90) days thereafter to sell or enter into an agreement (pursuant to which the sale of New Securities covered thereby shall be closed, if at all, within ninety (90) days from the date of said agreement) to sell that portion of the New Securities with respect to which the Investors’ right of first refusal option set forth in this Section 4.1 was not exercised, at a price and upon terms no more favorable to the purchasers thereof than specified in the Company’s notice to Investors delivered pursuant to Section 4.1(b). In the event the Company has not sold such New Securities within such ninety (90) day period following the Election Period, or such ninety (90) day period following the date of said agreement, the Company shall not thereafter issue or sell any New Securities, without first again offering such securities to the Investors in the manner provided in this Section 4.1.

(d) The right of first refusal granted under this Agreement shall expire upon, and shall not be applicable to, the Company’s Initial Public Offering.

SECTION 5 COVENANTS OF THE INVESTORS

5.1 Buy-Out Option.

(a) Bio and Maxygen hereby agree and acknowledge that, on the terms and conditions set forth in this Section 5.1, Bio has the right to purchase all, but not part, of the Series A Units and Conversion Units (or, following the Entity Conversion, any Conversion Stock) held by Maxygen at any time prior to the Option Expiration Date (the “Buy-Out Units,” and the right to purchase such Buy-Out Units, the “Buy-Out Option”) and, upon exercise of such Buy-Out Option

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by Bio, Maxygen shall sell to Bio all such Buy-Out Units, notwithstanding any provision of this Agreement or any of the Transaction Agreements to the contrary. Such Buy-Out Option may be exercised by Bio, in its sole and absolute discretion at any time and from time to time, until September 18, 2012 (the “Option Expiration Date”), by giving written notice to Maxygen, pursuant to the form attached hereto as Exhibit C (the “Option Notice”). The exercise price for the Buy-Out Units (the “Exercise Price”) is set forth on Schedule 5.1 hereof. The Option Notice shall specify the Exercise Price Bio shall pay to Maxygen, with the date that Bio exercises the Buy-Out Option being the relevant date for determining the Exercise Price to be paid in accordance with Schedule 5.1 hereto. Each of Bio and Maxygen covenants that it shall not Transfer any Units or Conversion Units held by Bio or Maxygen, as the case may be, at any time prior to the Option Expiration Date, except as in accordance with this Section 5.1 or in a Permitted Transfer. “Permitted Transfer” means any Transfer (either by operation of law or otherwise) made by either of Bio or Maxygen to (i) an entity that acquires all or substantially all of the business or assets of Bio or Maxygen, as the case may be, whether by merger, reorganization, acquisition, asset sale or otherwise, or (ii) a Related Entity of Bio or Maxygen, as the case may be, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement (including this Section 5.1).

(b) Upon the delivery of the Option Notice by Bio to Maxygen on or before the Option Expiration Date, the Buy-Out Option shall be deemed exercised and the parties hereto agree to work in good faith and use their reasonable best efforts to consummate the Option Closing as quickly as possible. If the Option Closing does not occur within 90 days of the delivery of the Option Notice by Bio to Maxygen, then the Buy-Out Option shall be forfeited and may not be exercised again; provided that the Buy-Out Option shall not be forfeited pursuant to the foregoing if (i) (A) Maxygen has failed to comply in any material respect with any of its obligations set forth in this paragraph (b) or paragraphs (c) or (d) below or in the agreement with respect to the sale and purchase of such Units referred to in paragraph (d) below respectively and (B) Bio has not failed to comply in any material respect with its obligations set forth in this paragraph (b) or in the agreement with respect to the sale and purchase of such Units referred to in paragraph (d) below or (ii) the Option Closing has not occurred within such period as a result of (A) the failure to obtain any consent, approval or authorization of any Governmental Entity required to consummate the Buy-Out Option or (B) any Governmental Entity having issued an Order or taken any other action enjoining, restraining or otherwise prohibiting the consummation of the Buy-Out Option.

(c) In the event that Bio informs Maxygen or the Company that the exercise of the Buy-Out Option requires the submission of a Hart-Scott-Rodino Act (the “HSR Act”) notification (or an antitrust notification in any other jurisdiction), as promptly as possible after the date of such notice but in any event no later than ten (10) days thereafter, each of Maxygen and Bio shall file with the Federal Trade Commission (the “FTC”) and the Antitrust Division of the United States Department of Justice (the “Antitrust Division”) a pre-merger notification in accordance with the HSR Act with respect to the purchase of all of Maxygen’s equity in the Company by Bio pursuant to the agreement defined in paragraph (d) below and shall submit an antitrust notification in any other jurisdiction as Bio and Maxygen reasonably believe is required with respect to Bio’s exercise of such option. Each of Maxygen and Bio shall furnish promptly to the FTC and the Antitrust Division any additional information requested by either of them pursuant to the HSR Act in connection with such filings. Each of Maxygen and Bio shall pay its own HSR Act filing fees or other filing fees, if any.

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(d) The closing of the purchase of the Buy-Out Units pursuant to Bio’s exercise of the Buy-Out Option shall be effected through a purchase agreement containing terms and conditions which are mutually agreeable to Bio and Maxygen; provided, that notwithstanding the foregoing, (i) such agreement shall contain representations and warranties (which representations and warranties, other than those representations and warranties relating to title and authority, shall not survive closing) and covenants of Maxygen relating to the Buy-Out Units and other matters which are substantially similar to those which it is making in the Asset Contribution Agreement with respect to the Contributed Assets subject to such modifications as may be appropriate to reflect the circumstances at the time and the form and nature of the transaction, and (ii) the Exercise Price shall be that established pursuant to Section 5.1(a). Bio and Maxygen shall negotiate such purchase agreement in good faith. At the closing of the Buy-Out Option (the “Option Closing”), Maxygen shall deliver a certificate or certificates representing all of the Buy-Out Units, duly endorsed in blank, or accompanied by assignments separate from the certificate or certificates representing such Buy-Out Units and made out in blank, with signatures guaranteed, together with evidence reasonably satisfactory to Bio of the payment of all applicable transfer Taxes. Each of Bio and Maxygen covenants that at no time prior to the earlier to occur of the Option Closing or the Buy-Out Expiration Date will any Units or Conversion Units held by Bio or Maxygen, as the case may be, be Transferred (except, with respect to Maxygen, to Bio or its Affiliate pursuant to this Section 5.1, or with respect to Bio or Maxygen in a Permitted Transfer or subjected to any liens, claims or encumbrances (except for those created by the Transaction Agreements or under applicable law)). At the Option Closing, Bio shall pay Maxygen the Exercise Price by wire transfer of same day funds.

(e) The Investors acknowledge and agree that the purchase of Maxygen’s ownership interest in the Company pursuant to the Buy-Out Option shall be treated for federal and applicable state and local income or franchise Tax purposes as a transaction described in Situation 1 of Revenue Ruling 99-6, 1999-1 C.B. 432, pursuant to which: (i) the Company will terminate under Section 708(b)(1)(A) of the Code when Bio purchases Maxygen’s entire interest in the Company and any vested Profits Interest Units, (ii) Maxygen and the holders of vested Profits Interest Units will be treated as selling their entire interest in the Company in accordance with Section 741 of the Code, and (iii) the Company will be deemed to make a liquidating distribution of all of its assets to Bio, Maxygen and the holders of vested Profits Interest Units, following which Bio will be treated as acquiring the assets deemed distributed to Maxygen and the holders of vested Profits Interest Units, so that, pursuant to Section 1012 of the Code, Bio’s tax basis in the Company’s assets attributable to Maxygen’s interest in the Company shall be the purchase price for their interests in the Company as determined pursuant to Section 5.1 hereof.

(f) Concurrently with or immediately after the Option Closing, Bio shall purchase for cash all vested Profits Interest Units held by the Company’s then-current and former Service Providers (as defined in the Equity Plan) and shall make adequate provisions for, and upon the subsequent vesting of, purchase, any unvested Profits Interest Units, in each case pursuant to the Equity Plan.

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(g) The Company and Bio hereby agree and acknowledge that if, at the Option Expiration Date, (i) the Buy-Out Option has not been exercised, (ii) the Company does not have in cash and cash equivalents less debt an amount greater than Twenty Million U.S. Dollars ($20,000,000), (iii) Astellas retains its license rights to products from the 4 Program under the Astellas Agreement (as such terms are defined in Article 1 of the Asset Contribution Agreement), and (iv) Bio has not exercised the Other Products Option (clauses (i) through (iv) collectively referred to as the “Loan Conditions”), the Company shall have the right (the “Loan Option”) to obtain from Astellas US or its assignee revolving loans up to the Maximum Loan Amount, upon the same terms and conditions set forth in the form of loan agreement attached as Exhibit D hereto (the “Loan Agreement”). The Company shall exercise the Loan Option by providing written notice to Astellas US or its assignee, such notice to be delivered no later than the later of (a) thirty (30) days of the Option Expiration Date, or (b) if the Buy-Out Option has been exercised but the Option Closing has not occurred, the 120th day after the delivery of the Option Notice by Bio to Maxygen (the “Loan Exercise Period”), along with a copy of the Loan Agreement executed by the Company. In the event the Loan Option has not been exercised within the Loan Exercise Period, neither Bio, Astellas US nor their respective assignees shall have an obligation to make any loans to the Company pursuant to this subparagraph. Following the valid exercise of the Loan Option, Astellas US shall promptly execute and deliver the Loan Agreement to the Company and its failure to so execute and deliver the Loan Agreement shall not relieve Astellas US of its obligations hereunder.

(h) Bio and Maxygen hereby agree and acknowledge that Bio’s rights under this Section 5.1 may be assigned to an Affiliate of Bio at any time prior to the Option Expiration Date. For the avoidance of doubt, Bio and Astellas shall remain fully and directly responsible for any and all of Bio’s obligations under this Section 5.1 regardless of whether Bio has assigned any or all of its rights to any of its Affiliates.

(i) If the Company effects the Entity Conversion, Bio and Astellas agree to promptly reimburse the Company (or its successor corporation) for costs and expenses (including reasonable attorneys’ fees) incurred by the Company to effect the Entity Conversion.

SECTION 6 MISCELLANEOUS

6.1 Amendment. Except as expressly provided herein, neither this Agreement nor any term hereof may be amended, waived, discharged or terminated other than by a written instrument referencing this Agreement and signed by the Company and each Investor; provided, however, that Securityholders purchasing equity securities (including any securities convertible into or exercisable for any equity securities) of the Company on or after the Option Expiration Date may become parties to this Agreement by executing a counterpart of this Agreement without any amendment of this Agreement pursuant to this paragraph or any consent or approval of any other Securityholder. Any such amendment, waiver, discharge or termination effected in accordance with this paragraph shall be binding upon each Securityholder and each future holder of all such securities of Securityholder. Each Securityholder acknowledges that by the operation of this paragraph, the Investors will have the right and power to diminish or eliminate all rights of such Securityholder under this Agreement.

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6.2 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent by electronic mail or otherwise delivered by hand, messenger or courier service addressed:

(a) if to Maxygen, Inc., to the address or electronic mail address of Maxygen, Inc. set forth in Exhibit A, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: David J. Segre and Tony Jeffries;

(b) if to Bio to the address or electronic mail address of Bio set forth in Exhibit A, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Morrison & Foerster LLP, 1290 Avenue of the Americas, New York, New York 10104, Attention: Michael Braun;

(c) if to any Investor or Securityholder not provided for in paragraphs (a) or (b), above, to such address or electronic mail address as shown in the Company’s records, or, until any such Investor or Securityholder so furnishes an address to the Company, then to the address of the last holder of such equity for which the Company has contact information in its records; or

(d) if to the Company, to the attention of the Chief Executive Officer or Chief Financial Officer of the Company at 515 Galveston Drive, Redwood City, CA 94063, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: David J. Segre and Tony Jeffries.

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given (i) if delivered by hand, messenger or courier service, when delivered (or if sent via a nationally-recognized overnight courier service, freight prepaid, specifying next-business-day delivery, two (2) Business Days after deposit with the courier), (ii) if sent via registered or certified mail, at the earlier of its receipt or five (5) days after the same has been deposited in a regularly-maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid, or (iii) if sent via electronic mail, when directed to the relevant electronic mail address, if sent during normal business hours of the recipient, or if not sent during normal business hours of the recipient, then on the recipient’s next Business Day in either case confirmed in writing.

Each Investor and Securityholder consents to the delivery of any notice to members given by the Company under the Delaware Limited Liability Company Act or the Certificate or the LLC Agreement by (i) electronic mail to the electronic mail address set forth above (or to any other electronic mail address for the Investor or Securityholder in the Company’s records), (ii) posting on an electronic network together with separate notice to the Investor or Securityholder of such specific

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posting or (iii) any other form of electronic transmission (as defined in §18-302 of the Delaware Limited Liability Company Act) directed to the Investor or Securityholder. This consent may be revoked by an Investor or Securityholder by written notice to the Company and may be deemed revoked in the circumstances specified in the LLC Agreement.

6.3 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of Delaware as applied to agreements entered into among Delaware residents to be performed entirely within Delaware, without regard to principles of conflicts of law that would result in the law of a jurisdiction other than the State of Delaware governing.

6.4 Successors and Assigns. Except as provided in this Section 6.4, this Agreement shall not be assignable or otherwise transferred, in whole or in part, by the Company or any Investor to any Third Party without the written consent of the other parties hereto, provided that this Agreement may without requiring the consent of the other parties be assigned, transferred, delegated or sublicensed in connection with the transfer of Units to (a) an entity that acquires all or substantially all of the business or assets of such party, whether by merger, reorganization, acquisition, asset sale or otherwise, or (b) any Related Entity of such party, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement and, prior to the Option Expiration Date, the Voting Agreement, the Co-Sale Agreement and the LLC Agreement. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the parties. Except as expressly provided in this Section 6.4, any attempted assignment or transfer of this Agreement shall be null and void.

6.5 [Reserved].

6.6 Entire Agreement. This Agreement and the exhibits hereto and the Transaction Agreements constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof and thereof. No party hereto shall be liable or bound to any other party in any manner with regard to the subjects hereof or thereof by any warranties, representations or covenants except as specifically set forth herein or therein.

6.7 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party to this Agreement upon any breach or default of any other party under this Agreement shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any kind or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party to this Agreement, shall be cumulative and not alternative.

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6.8 Severability. If any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Agreement, and such court will replace such illegal, void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Agreement shall be enforceable in accordance with its terms.

6.9 Titles and Subtitles. The titles and subtitles used in this Agreement are used for convenience only and are not to be considered in construing or interpreting this Agreement. All references in this Agreement to sections, paragraphs and exhibits shall, unless otherwise provided, refer to sections and paragraphs hereof and exhibits attached hereto.

6.10 Counterparts. This Agreement may be executed and delivered by PDF signature and in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

6.11 Jurisdiction; Venue. With respect to any disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, any court in the State of Delaware having subject matter jurisdiction (or in the event of exclusive federal jurisdiction, the courts of the District of Delaware).

6.12 Further Assurances. Each party hereto agrees to execute and deliver, by the proper exercise of its corporate, limited liability company, partnership or other powers, all such other and additional instruments and documents and do all such other acts and things as may be necessary to more fully effectuate this Agreement.

6.13 Specific Performance. It is agreed and understood that monetary damages would not adequately compensate an injured party for the breach of this Agreement by any party, that this Agreement shall be specifically enforceable, and that any breach or threatened breach of this Agreement shall be the proper subject of a temporary or permanent injunction or restraining order. Further, each party waives any claim or defense that there is an adequate remedy at law for such breach or threatened breach.

6.14 Termination upon Change of Control. Notwithstanding anything to the contrary herein, this Agreement (excluding any then existing obligations) shall terminate upon (a) the acquisition of the Company by another entity by means of any transaction or series of related transactions to which the Company is party (including, without limitation, any security acquisition, reorganization, merger or consolidation but excluding any bona fide sale of stock for capital raising purposes) other than a transaction or series of transactions in which the holders of the voting securities of the Company outstanding immediately prior to such transaction continue to retain (either by such voting securities remaining outstanding or by such voting securities being converted into voting securities of the surviving entity), as a result of equity in the Company held by such holders prior to such transaction, at least fifty percent (50%) of the total voting power represented by

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the voting securities of the Corporation or such surviving entity outstanding immediately after such transaction or series of transactions; (b) a sale, lease, exclusive license or other conveyance of all or substantially all of the assets of the Company; or (c) the consummation of the transaction resulting from the exercise of the Buy-Out Option.

6.15 Conflict. In the event of any conflict between the terms of this Agreement and the LLC Agreement, the terms of the LLC Agreement, as the case may be, will control. In the event of any conflict between the Company’s books and records and this Agreement or any notice delivered hereunder, the Company’s books and records will control absent fraud or error.

6.16 Attorneys’ Fees. In the event that any suit or action is instituted to enforce any provision in this Agreement, the prevailing party in such dispute shall be entitled to recover from the losing party such reasonable fees and expenses of attorneys and accountants, which shall include, without limitation, all fees, costs and expenses of appeals.

6.17 Aggregation of Company Securities. All securities held or acquired by affiliated entities or persons shall be aggregated together for purposes of determining the availability of any rights under this Agreement. For the avoidance of doubt, none of the Company, Maxygen or Bio shall be considered to be “affiliated entities” of one another for the purposes of this Agreement.

6.18 Jury Trial. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING (WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATED TO THIS AGREEMENT. This paragraph shall not restrict a party from exercising remedies under the Uniform Commercial Code or from exercising pre-judgment remedies under applicable law.

(signature page follows)

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The parties are signing this Investors’ Rights Agreement as of the date stated in the introductory clause.

PERSEID THERAPEUTICS LLC
a Delaware limited liability company
By:	/s/ Grant Yonehiro
Name:	Grant Yonehiro
Title:	CEO & President

[SIGNATURE PAGE TO THE INVESTORS’ RIGHTS AGREEMENT]

The parties are signing this Investors’ Rights Agreement as of the date stated in the introductory clause.

INVESTOR
Astellas Bio Inc.
By:	/s/ Kazunori Okimura
Name:	Kazunori Okimura
Title:	Secretary

[SIGNATURE PAGE TO THE INVESTORS’ RIGHTS AGREEMENT]

The parties are signing this Investors’ Rights Agreement as of the date stated in the introductory clause.

INVESTOR
Maxygen, Inc.
By:	/s/ Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

[SIGNATURE PAGE TO THE INVESTORS’ RIGHTS AGREEMENT]

The parties are signing this Investors’ Rights Agreement as of the date stated in the introductory clause.

Astellas Pharma Inc.
(Solely for the purposes of Sections 5.1(h) and 5.1(i))
By:	/s/ Masafumi Nogimori
Name:	Masafumi Nogimori
Title:	Representative Director, President & CEO

[SIGNATURE PAGE TO THE INVESTORS’ RIGHTS AGREEMENT]

The parties are signing this Investors’ Rights Agreement as of the date stated in the introductory clause.

Astellas US Holding, Inc.
(Solely for the purposes of Section 5.1(g))
By:	/s/ Linda F. Friedman
Name:	Linda F. Friedman
Title:	Secretary

[SIGNATURE PAGE TO THE INVESTORS’ RIGHTS AGREEMENT]

EXHIBIT A

INVESTORS

Astellas Bio Inc.

Three Parkway

North Deerfield, IL 60015-2458

Email: masaki.doi@jp.astellas.com and kazunori.okimura@jp.astellas.com

Maxygen, Inc.

515 Galveston Drive

Redwood City, CA 94063

Email: corporatesecretary@maxygen.com

EXHIBIT B

NOTICE AND WAIVER/ELECTION OF

RIGHT OF FIRST REFUSAL

I do hereby waive or exercise, as indicated below, my rights of first refusal under the Investors’ Rights Agreement dated as of September 18, 2009 (the “Agreement”):

Waiver of 15 days’ notice period in which to exercise right of first refusal: (please check only one)

(    ) WAIVE in full, on behalf of all Holders, the 15-day notice period provided to exercise my right of first refusal granted under the Agreement.

(    ) DO NOT WAIVE the notice period described above.

Issuance and Sale of New Securities: (please check only one):

(    ) WAIVE in full the right of first refusal granted under the Agreement with respect to the issuance of the New Securities.

(    ) ELECT TO PARTICIPATE in $            (please provide amount) in New Securities proposed to be issued by             , a Delaware corporation, representing LESS than my pro rata portion of the aggregate of $             in New Securities being offered in the financing.

(    ) ELECT TO PARTICIPATE in $             in New Securities proposed to be issued by             , a Delaware corporation, representing my FULL pro rata portion of the aggregate of $            in New Securities being offered in the financing.

(    ) ELECT TO PARTICIPATE in my full pro rata portion of the aggregate of $             in New Securities being made available in the financing AND, to the extent available, the greater of (x) an additional $             (please provide amount) or (y) my pro rata portion of any remaining investment amount available in the event other Investors do not exercise their full rights of first refusal with respect to the $             in New Securities being offered in the financing.

Date:
	(Print investor name)
	(Signature)
	(Print name of signatory, if signing for an entity)
	(Print title of signatory, if signing for an entity)

This is neither a commitment to purchase nor a commitment to issue the New Securities described above. Such issuance can only be made by way of definitive documentation related to such issuance. The company will supply you with such definitive documentation upon request or if you indicate that you would like to exercise your first offer rights in whole or in part.

EXHIBIT C

FORM OF OPTION NOTICE

[Date]

By Overnight Delivery

Maxygen, Inc.

515 Galveston Drive

Redwood City, CA 94063

Attention: Chief Executive Officer

Re: Notice of Exercise of Buy-Out Option

Dear Sir or Madam:

Reference is made to the Investors’ Rights Agreement dated as of September 18, 2009 (the “Investors’ Rights Agreement”) by and among Maxygen, Inc. (“Maxygen”), Perseid Therapeutics LLC (the “Company”) and Astellas Bio Inc. (“Bio”). Capitalized terms used herein, unless otherwise defined herein, shall have the respective meanings assigned to them in the Investors’ Rights Agreement.

This letter serves as the written notice of Bio under Section 5.1(a) of the Investors’ Rights Agreement of Bio’s election to purchase the Buy-Out Units at the Exercise Price of $[            ], as determined in accordance with Schedule 5.1 of the Investors’ Rights Agreement. We look forward to working with you to expeditiously close the purchase of the Buy-Out Units in accordance with Section 5.1(b) of the Investors’ Rights Agreement.

Very Truly Yours,

Astellas Bio Inc.

By:

Name:

Title:

EXHIBIT D

LOAN AGREEMENT

[Intentionally omitted]

The registrant agrees to furnish to the Securities and Exchange Commission upon request a copy of any omitted schedule or exhibit.

SCHEDULE 5.1

OPTION EXERCISE PRICE

	Option Notice dated on or before December 18th		Option Notice dated on or before March 18th		Option Notice dated on or before June 18th		Option Notice dated on or before September 18th
Year 1	$	53 million	$	57 million	$	61 million	$	65 million
Year 2	$	70 million	$	76 million	$	81 million	$	88 million
Year 3	$	95 million	$	104 million	$	113 million	$	123 million

EX-2.1.6

Exhibit 2.1.6

PERSEID THERAPEUTICS LLC

CO-SALE AGREEMENT

September 18, 2009

TABLE OF CONTENTS

		Page
SECTION 1 DEFINITIONS		1
1.1	Certain Definitions	1
SECTION 2 RESTRICTIONS ON TRANSFER		3
2.1	General	3
2.2	Notice of Proposed Transfer	3
SECTION 3 RIGHT OF CO-SALE		3
3.1	Exercise by the Remaining Investor	3
3.2	Closing; Consummation of the Co-Sale	4
3.3	Exclusion from Co-Sale Right	4
3.4	Multiple Series, Class or Type of Units	4
3.5	Seller’s Right To Transfer	4
SECTION 4 CONDITIONS TO VALID TRANSFER		5
4.1	Generally	5
4.2	Put Right	5
SECTION 5 RESTRICTIVE LEGEND AND STOP TRANSFER ORDERS		5
5.1	Legend	5
5.2	Stop Transfer Instructions	6
SECTION 6 TERMINATION		6
6.1	Termination	6
SECTION 7 MISCELLANEOUS		6
7.1	Notices	6
7.2	Successors and Assigns	7
7.3	Severability	7
7.4	Amendment	7
7.5	Governing Law	7
7.6	Counterparts	7
7.7	Further Assurances	8
7.8	Conflict	8
7.9	Attorney’s Fees	8
7.10	Titles and Subtitles	8
7.11	Entire Agreement	8

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TABLE OF CONTENTS

(Continued)

		Page
7.12	Specific Performance	8
7.13	Delays or Omissions	8
7.14	Jurisdiction; Venue	8
7.15	Aggregation of Units	9
7.16	Jury Trial	9

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PERSEID THERAPEUTICS LLC

CO-SALE AGREEMENT

This Co-Sale Agreement (this “Agreement”) is dated as of September 18, 2009, and is between Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), Maxygen, Inc., a Delaware corporation (“Maxygen”), and Astellas Bio Inc., a Delaware corporation (“Bio”) (each of Bio and Maxygen an “Investor,” and collectively, the “Investors”). All capitalized terms used and not defined herein shall have such meanings as set forth in the Master Joint Venture Agreement by and between Maxygen, Astellas Pharma Inc. and Bio dated as of June 30, 2009 (the “Master Joint Venture Agreement”).

RECITALS

The Investors are parties to the Series A and Series B Preferred Unit Purchase Agreement of even date herewith, between the Company and the Investors (the “Purchase Agreement”), and it is a condition to the closing of the sale of the Series A Preferred Units and Series B Preferred Units to the Investors that the Investors and the Company execute and deliver this Agreement.

The parties therefore agree as follows:

SECTION 1

DEFINITIONS

1.1 Certain Definitions. For purposes of this Agreement, the following terms have the following meanings:

(a) “Buy-Out Option” has such meaning as set forth in Section 5.1 of the Investors’ Rights Agreement.

(b) “Common Units” means the common units of the Company.

(c) “Change of Control” means (a) the acquisition of the Company by another entity by means of any transaction or series of related transactions to which the Company is party (including, without limitation, any stock acquisition, reorganization, merger or consolidation) other than a transaction or series of transactions in which the holders of the voting securities of the Company outstanding immediately prior to such transaction continue to retain (either by such voting securities remaining outstanding or by such voting securities being converted into voting securities of the surviving entity), as a result of units in the Company held by such holders prior to such transaction, at least fifty percent (50%) of the total voting power represented by the voting securities of the Company or such surviving entity outstanding immediately after such transaction or series of transactions, excluding any bona fide sale of units for capital raising purposes, or (b) the sale, lease, exclusive license or other conveyance of all or substantially all of the assets of the Company.

(d) “Convertible Securities” means all then outstanding options, warrants, rights, convertible notes, preferred units or other securities of the Company, directly or indirectly convertible into, or exercisable for, Common Units.

(e) “Days” means calendar days; provided that if any day on which a period specified in this Agreement would otherwise terminate falls on a weekend or a federal holiday, the term “day” shall mean the next Business Day.

(f) “Preferred Units” means the Series A Preferred Units and Series B Preferred Units of the Company.

(g) “Remaining Investor” means an Investor that is not proposing to Transfer Seller Units.

(h) “Rights of Co-Sale” means the right of co-sale in Section 3 provided to the Remaining Investor.

(i) “Seller” means an Investor proposing to Transfer Seller Units.

(j) “Seller Units” means all Common Units, Preferred Units and Convertible Securities of the Company owned as of the date hereof or hereafter acquired by an Investor, as adjusted for any unit splits, unit dividends, combinations, subdivisions, recapitalizations and the like.

(k) “Series A Preferred Units” means all of the Series A Preferred Units issued pursuant to the Purchase Agreement.

(l) “Series B Preferred Units” means all of the Series B Preferred Units issued pursuant to the Purchase Agreement.

(m) “Transfer,” “Transferring,” “Transferred,” or words of similar import, mean and include any sale, assignment, encumbrance, hypothecation, pledge, conveyance in trust, gift, transfer by bequest, devise or descent, or other transfer or disposition of any kind, including but not limited to transfers to receivers, levying creditors, trustees or receivers in bankruptcy proceedings or general assignees for the benefit of creditors, whether voluntary or by operation of law, directly or indirectly, except:

(i) any bona fide pledge made pursuant to a bona fide loan transaction that creates a mere security interest, if the pledgee executes a counterpart copy of this Agreement and becomes bound thereby as a Seller in the event that and to the extent that such pledgee ever acquires ownership of such Units; and

(ii) any transfer (either by operation of law or otherwise) made by either of Bio or Maxygen to (i) an entity that acquires all or substantially all of the business or assets of Bio or Maxygen (including, in the case of Maxygen all or substantially all of the assets of Maxygen other than the Buy-Out Units), as the case may be, whether by merger, reorganization, acquisition, asset sale or otherwise, or (ii) an Affiliate of Bio or Maxygen, as the case may be (including, for the avoidance of doubt and without limitation, a liquidating trust or similar entity), in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement and, prior to the Option Expiration Date (as defined in Section 5.1(a) of the Investors’ Rights Agreement), the Investors’ Rights Agreement, the Voting Agreement and the LLC Agreement.

If a Seller plans to make any of the above excepted transfers, then, prior to transferring its Seller Units, the Seller shall deliver to the Company a written notice stating: (A) Seller’s bona fide intention to make an excepted transfer of its Seller Units; (B) the name, address and phone number of each proposed transferee; (C) the aggregate number of Seller Units to be transferred to each proposed transferee; and (D) the section in this agreement upon which Seller is relying in making an excepted transfer.

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SECTION 2

RESTRICTIONS ON TRANSFER

2.1 General. Prior to the Option Expiration Date, no Party may Transfer their Units or Conversion Units (except as in accordance with Section 5.1 of the Investors’ Rights Agreement or in a Permitted Transfer (as defined in the Investors’ Rights Agreement)) pursuant to Sections 5.1 and 6.4 of the Investors’ Rights Agreement. On or after the Option Expiration Date (as defined the Investors’ Rights Agreement), before a Seller may Transfer any Seller Units, Seller must comply with the provisions of Section 2.2 and Section 3 hereof. Each Investor represents and warrants that it is the sole legal and beneficial owner of its Seller Units and, subject to any restrictions imposed under the Company’s certificate of formation, as filed on September 8, 2009, and as amended from time to time (the “Certificate”) or the Company’s limited liability company agreement, as amended from time to time (the “LLC Agreement”), or under any restricted units purchase agreement with the Company, that no other person or entity has any interest (other than a community property interest) in such units. Each of Bio and Maxygen acknowledges and agrees that it is subject to certain restrictions on the Transfer of its Seller Units prior to the Option Expiration Date pursuant to Section 5 of the Investors’ Rights Agreement and that such restrictions are in lieu of the restrictions on transfer set forth in this Agreement, and that none of the restrictions on transfer set forth in this Agreement shall apply, with respect to any Transfer of Seller Units prior to the Option Expiration Date.

2.2 Notice of Proposed Transfer. On or after the Option Expiration Date, prior to Seller Transferring any of its Seller Units, Seller shall deliver to the Company and the Remaining Investor a written notice (the “Transfer Notice”) in substantially the form attached hereto as Exhibit B, stating: (i) Seller’s bona fide intention to Transfer such Seller Units; (ii) the name, address and phone number of each proposed purchaser or other transferee (each, a “Proposed Transferee”); (iii) the aggregate number of Seller Units proposed to be Transferred to each Proposed Transferee (the “Offered Units”); (iv) the bona fide cash price or, in reasonable detail, other consideration for which Seller proposes to Transfer the Offered Units (the “Offered Price”); and (v) the Remaining Investor’s right to exercise its Right of Co-Sale with respect to the Offered Units. Attached to such Transfer Notice shall be a copy of the purchase agreement (the “Transfer Agreement”) pursuant to which the Seller intends to Transfer its Seller Units. If the Transfer Agreement is not available at the time that the Transfer Notice is sent to the Company and the Remaining Investor, then the Seller agrees to provide the Transfer Agreement to the Company and the Remaining Investor promptly once a reasonably final draft thereof is available and in any event not less than five (5) days prior to the conclusion of the Initial Exercise Period.

SECTION 3

RIGHT OF CO-SALE

3.1 Exercise by the Remaining Investor.

(a) Subject to the limitations of this Section 3, the Remaining Investor shall have the right to participate in such sale of the Offered Units on the same terms and conditions as specified in the Transfer Agreement and the Transfer Notice, to the extent described in Section 3.1(b). To exercise its rights hereunder, the Remaining Investor (the “Selling Investor”) must have provided a written notice to Seller within the twenty (20) days (the “Initial Exercise Period”) after the last date on which the Transfer Notice is, pursuant to Section 7.1, deemed to have been delivered to the Company and the Remaining Investor, indicating the number of units it holds that it wishes to sell pursuant to this Section 3.1.

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(b) The Selling Investor will be entitled to sell up to its pro rata share of the Offered Units, which shall be equal to the product obtained by multiplying (x) the number of Offered Units by (y) a fraction, (i) the numerator of which shall be the number of Common Units (assuming full conversion or exercise of all Preferred Units and Convertible Securities into Common Units) held on the date of the Transfer Notice by such Selling Investor and (ii) the denominator of which shall be the number of Common Units (assuming full conversion or exercise of all Preferred Units and Convertible Securities into Common Units) held on the date of the Transfer Notice by Seller and the Selling Investors (“Pro Rata Co-Sale Share”).

(c) Within ten (10) days after the expiration of the Initial Exercise Period, Seller will give written notice to the Company and the Selling Investor specifying the number of Offered Units to be sold by the Selling Investor exercising its Right of Co-Sale (the “Co-Sale Confirmation Notice”). The Co-Sale Confirmation Notice shall also specify the number of Offered Units not being sold by the Selling Investor, if any, pursuant to Section 3.

3.2 Closing; Consummation of the Co-Sale. Subject to compliance with applicable state and federal securities laws, the sale of the Offered Units by the Selling Investor shall occur on the date of the Transfer of the Offered Units by Seller, which date shall be within ten (10) days after the delivery of the Co-Sale Confirmation Notice (the “Co-Sale Closing”). If the Selling Investor exercised the Right of Co-Sale in accordance with this Section 3, then such Selling Investor shall deliver to Seller at or before the Co-Sale Closing one or more certificates, properly endorsed for Transfer, representing the number of Offered Units to which the Selling Investor is entitled to sell pursuant to this Section 3. At the Co-Sale Closing, Seller shall cause such certificates or other instruments to be Transferred and delivered to the Transferee pursuant to the terms and conditions specified in the Transfer Agreement and the Transfer Notice, and Seller will remit, or will cause to be remitted, to the Selling Investor, at the Co-Sale Closing, that portion of the proceeds of the Transfer to which the Selling Investor is entitled by reason of the Selling Investor’s participation in such Transfer pursuant to the Right of Co-Sale.

3.3 Exclusion from Co-Sale Right. This Right of Co-Sale shall not apply with respect to Common Units (including units issued or issuable upon conversion of Preferred Units) sold or to be sold by the Selling Investor pursuant to the Put Right set forth in Section 4.2.

3.4 Multiple Series, Class or Type of Units. If the Offered Units consist of more than one series, class or type of security, Seller has the right to Transfer hereunder each such series, class or type; provided that if the Selling Investor does not hold any of such series, class or type and the Proposed Transferee is not willing, at the Co-Sale Closing, to purchase some other series, class or type of security from such Selling Investor, or is unwilling to purchase any security from such Selling Investor at the Co-Sale Closing, then such Selling Investor will have the put right (the “Put Right”) set forth in Section 4.2.

3.5 Seller’s Right To Transfer. If any of the Offered Units remain available after the exercise of all Rights of Co-Sale, then the Seller shall be free to Transfer, subject to Section 4, any such remaining units to the Proposed Transferee at the Offered Price or a higher price in accordance with the terms set forth in the Transfer Notice; provided, however, that if the Offered Units are not so Transferred during the sixty (60) day period following the deemed delivery of the Transfer Notice, then Seller may not Transfer any of such remaining Offered Units without complying again in full with the provisions of this Agreement.

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SECTION 4

CONDITIONS TO VALID TRANSFER

4.1 Generally. Any attempt by Seller to Transfer any Seller Units in violation of any provision of this Agreement will be void. No securities shall be transferred by Seller unless (i) such Transfer is made in compliance with all of the terms of this Agreement and all applicable federal and state securities laws and (ii) prior to such Transfer, the transferee or transferees sign a counterpart to this Agreement pursuant to which it or they agree to be bound by the terms of this Agreement, the Investors’ Rights Agreement, the Voting Agreement, and the LLC Agreement. The Company will not be required to (i) transfer on its books any units that have been Transferred in violation of any provisions of this Agreement or (ii) to treat as owner of such units, or accord the right to vote or pay dividends to any purchaser, donee or other transferee to whom such units may have been so Transferred.

4.2 Put Right. If a Seller Transfers any Seller Units in contravention of the Right of Co-Sale under this Agreement (a “Prohibited Transfer”), or if the Proposed Transferee of Offered Units desires to purchase a class, series or type of units offered by Seller but not held by a Selling Investor, or the Proposed Transferee is unwilling to purchase any securities from a Selling Investor, such Selling Investor may, by delivery of written notice to such Seller (a “Put Notice”) within ten (10) days after the later of (i) the Co-Sale Closing and (ii) the date on which such Selling Investor becomes aware of the Prohibited Transfer or the terms thereof, require such Seller to purchase from such Selling Investor on the date of the Co-Sale Closing that number of Preferred Units (on an as-converted basis) or Common Units (subject to Section 4.2(b)) that is equal to the number of Offered Units such Selling Investor would have been entitled to Transfer to the purchaser (the “Put Units”). Such sale shall be made on the following terms and conditions:

(a) The price per unit at which the Put Units are to be sold to Seller shall be equal to the price per unit that the Selling Investor would have received at the Co-Sale Closing of such Prohibited Transfer if such Selling Investor had sold such Put Units at the Co-Sale Closing. Such purchase price of the Put Units shall be paid in cash or such other consideration as Seller received in the Prohibited Transfer or at the Co-Sale Closing.

(b) The Put Units to be sold to Seller shall be of the same class or type as Transferred in the Prohibited Transfer or at the Co-Sale Closing if such Selling Investor then owns securities of such class or type to the extent of such securities owned by such Selling Investor. If such Selling Investor does not own any or owns a lesser number of such class or type, the Put Units shall be Common Units (or Preferred Units convertible into Common Units at the option of the holder thereof) to the extent of the difference.

(c) The closing of such sale to Seller will occur within ten (10) days after the date of such Selling Investor’s Put Notice to such Seller. At such closing, the Selling Investor shall deliver to Seller the certificate or certificates representing the Put Units to be sold, each certificate to be properly endorsed for transfer, and immediately upon receipt thereof, such Seller shall pay the aggregate purchase price therefor, and the amount of reimbursable fees and expenses, as specified in Section 4.2(a).

SECTION 5

RESTRICTIVE LEGEND AND STOP TRANSFER ORDERS

5.1 Legend. Each Investor understands and agrees that the Company will cause the legend set forth in Section 3.8 of the Purchase Agreement, or a legend substantially equivalent thereto, to be placed upon any certificate(s) or other documents or instruments evidencing ownership of Seller Units by such Investor.

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5.2 Stop Transfer Instructions. In order to ensure compliance with the restrictions referred to herein, each Seller agrees that the Company may issue appropriate “stop transfer” certificates or instructions in the event of a Transfer in violation of any provision of this Agreement and that it may make appropriate notations to the same effect in its records.

SECTION 6

TERMINATION

6.1 Termination. This Agreement shall terminate upon the earliest to occur of (i) the filing of a registration statement with respect to a Qualified Public Offering (as defined in the Investors’ Rights Agreement), (ii) the date on which this Agreement is terminated by a writing executed by each of the Investors, (iii) the dissolution or winding-up of the Company, or (iv) immediately prior to the effective date of a Change of Control. A “Qualified Public Offering” means a bona fide, firm commitment underwritten public offering by the Company pursuant to an effective registration statement filed under the Securities Act of 1933, as amended, covering the offer and sale of the Conversion Stock (as defined in the Investors’ Rights Agreement), provided that the pre-offering valuation of the Company is at least $200,000,000 and the aggregate gross proceeds to the Company are not less than $50,000,000.

SECTION 7

MISCELLANEOUS

7.1 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent by electronic mail or otherwise delivered by hand, messenger or courier service addressed:

(a) if to Maxygen, to the address or electronic mail address of Maxygen as set forth in Exhibit A, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: Tony Jeffries;

(b) if to Bio, to the address or electronic mail address of Bio as set forth in Exhibit A, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Morrison & Foerster LLP, 1290 Avenue of the Americas, New York, New York 10104, Attention: Michael Braun; or

(c) if to the Company, to the attention of the Chief Executive Officer or Chief Financial Officer of the Company at 515 Galveston Drive, Redwood City, CA 94063, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: Tony Jeffries.

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given (i) if delivered by hand, messenger or courier service, when delivered (or if sent via a nationally-recognized overnight courier service, freight prepaid, specifying next-business-day delivery, two (2) Business Days after deposit with the courier), (ii) if sent via registered or certified mail, at the earlier of its receipt or five (5) days after the same has been deposited in a regularly-maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid, or (iii) if sent via electronic mail, when directed to the relevant electronic mail address, if sent during normal business hours of the recipient, or if not sent during normal business hours of the recipient, then on the recipient’s next Business Day and in either case later confirmed in writing.

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Each Investor consents to the delivery of any notice to members given by the Company under the Delaware Limited Liability Company Act or the Certificate or the LLC Agreement by (i) electronic mail to the electronic mail address set forth above (or to any other electronic mail address for the Investor in the Company’s records), (ii) posting on an electronic network together with separate notice to the Investor of such specific posting or (iii) any other form of electronic transmission (as defined in §18-302 of the Delaware Limited Liability Company Act) directed to the Investor. This consent may be revoked by an Investor by written notice to the Company and may be deemed revoked in the circumstances specified in the LLC Agreement.

7.2 Successors and Assigns. Except as provided in this Section 7.2, this Agreement shall not be assignable or otherwise transferred, in whole or in part, by the Company or any Investor to any third party without the written consent of the other parties hereto, provided that this Agreement may without requiring the consent of the other parties be assigned, transferred, delegated or sublicensed in connection with the transfer of Units to (a) an entity that acquires all or substantially all of the business or assets of such party, whether by merger, reorganization, acquisition, asset sale or otherwise, or (b) any Related Entity (as defined in the Investors’ Rights Agreement) of such party, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement and, prior to the Option Expiration Date (as defined in the Investors’ Rights Agreement), the Investors’ Rights Agreement, the Voting Agreement and the LLC Agreement. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the parties. Except as expressly provided in this Section 7.2, any attempted assignment or transfer of this Agreement shall be null and void.

7.3 Severability. If any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Agreement, and such court will replace such illegal, void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Agreement shall be enforceable in accordance with its terms.

7.4 Amendment. Except as expressly provided herein, neither this Agreement nor any term hereof may be amended, waived, discharged or terminated other than by a written instrument referencing this Agreement and signed by the Company and each Investor; provided, however, that any Person purchasing equity securities (including any securities convertible into or exercisable for any equity securities) of the Company on or after the Option Expiration Date may become parties to this Agreement by executing a counterpart of this Agreement without any amendment of this Agreement pursuant to this paragraph or any consent or approval of any other Investor. Any such amendment, waiver, discharge or termination effected in accordance with this paragraph shall be binding upon each future holder of Preferred Units with rights under this Agreement.

7.5 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of Delaware as applied to agreements entered into among Delaware residents to be performed entirely within Delaware, without regard to principles of conflicts of law.

7.6 Counterparts. This Agreement may be executed and delivered by PDF signature and in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

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7.7 Further Assurances. Each party hereto agrees to execute and deliver, by the proper exercise of its corporate, limited liability company, partnership or other powers, all such other and additional instruments and documents and do all such other acts and things as may be necessary to more fully effectuate this Agreement.

7.8 Conflict. In the event of any conflict between the terms of this Agreement and the Certificate or Bylaws, the terms of the Certificate or Bylaws, as the case may be, will control. In the event of any conflict between the Company’s books and records and this Agreement or any notice delivered hereunder, the Company’s books and records will control absent fraud or error.

7.9 Attorney’s Fees. In the event that any suit or action is instituted to enforce any provision in this Agreement, the prevailing party in such dispute shall be entitled to recover from the losing party such reasonable fees and expenses of attorneys and accountants, which shall include, without limitation, all fees, costs and expenses of appeals.

7.10 Titles and Subtitles. The titles and subtitles used in this Agreement are used for convenience only and are not to be considered in construing or interpreting this Agreement. All references in this Agreement to sections, paragraphs and exhibits shall, unless otherwise provided, refer to sections and paragraphs hereof and exhibits and schedules attached hereto.

7.11 Entire Agreement. This Agreement and the exhibits hereto and the Transaction Agreements constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof and thereof. No party hereto shall be liable or bound to any other party in any manner with regard to the subjects hereof or thereof by any warranties, representations or covenants except as specifically set forth herein or therein.

7.12 Specific Performance. It is agreed and understood that monetary damages would not adequately compensate an injured party for the breach of this Agreement by any party, that this Agreement shall be specifically enforceable, and that any breach or threatened breach of this Agreement shall be the proper subject of a temporary or permanent injunction or restraining order. Further, each party waives any claim or defense that there is an adequate remedy at law for such breach or threatened breach.

7.13 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party to this Agreement upon any breach or default of any other party under this Agreement shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any kind or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party to this Agreement, shall be cumulative and not alternative.

7.14 Jurisdiction; Venue. With respect to any disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, any court in the State of Delaware having subject matter jurisdiction (or in the event of exclusive federal jurisdiction, the courts of the District of Delaware).

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7.15 Aggregation of Units. All of the Company’s units held or acquired by affiliated entities or persons of an Investor shall be aggregated together for purposes of determining the availability of any rights under this Agreement which are triggered by the beneficial ownership of a threshold number of the Company’s units. For the avoidance of doubt, none of the Company, Maxygen or Bio shall be considered to be “affiliated entities” of one another for the purposes of this Agreement.

7.16 Jury Trial. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING (WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATED TO THIS AGREEMENT. This paragraph shall not restrict a party from exercising remedies under the Uniform Commercial Code or from exercising pre-judgment remedies under applicable law.

(signature page follows)

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The parties are signing this Co-Sale Agreement as of the date stated in the introductory clause.

PERSEID THERAPEUTICS LLC a Delaware limited liability company
By:	/s/    Grant Yonehiro
Name:	Grant Yonehiro
Title:	Chief Executive Officer and President

[SIGNATURE PAGE TO THE CO-SALE AGREEMENT]

The parties are signing this Co-Sale Agreement as of the date stated in the introductory clause.

INVESTOR
Astellas Bio Inc.
By:	/s/    Kazunori Okimura
Name:	Kazunori Okimura
Title:	Secretary

[SIGNATURE PAGE TO THE CO-SALE AGREEMENT]

The parties are signing this Co-Sale Agreement as of the date stated in the introductory clause.

INVESTOR
Maxygen, Inc.
By:	/s/    Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

[SIGNATURE PAGE TO THE CO-SALE AGREEMENT]

EXHIBIT A

INVESTORS

Series A Preferred

Name and Address

Maxygen, Inc.

515 Galveston Drive

Redwood City, CA 94063

USA

Email: corporatesecretary@maxygen.com

Series B Preferred

Name and Address

Astellas Bio Inc.

Three Parkway

North Deerfield, IL 60015-2458

Email: masaki.doi@jp.astellas.com and kazunori.okimura@jp.astellas.com

EXHIBIT B

FORM OF

NOTICE OF UNIT TRANSFER

Notice of Transfer

I intend to transfer the Company’s units as indicated below (the “Offered Units”).

Notice of Rights

Pursuant to the Co-Sale Agreement, dated as of September 18, 2009 (the “Agreement”), I write to inform you of your Right of Co-Sale (as defined in the Agreement) with respect to the Offered Units. If you choose to do so, you may exercise this right with respect to the Offered Units by returning this notice to me, at the address below, with a copy to [                            ]. If you decline your right to do so, you do not need to return anything. Your failure to return this notice on a timely basis will indicate that you have declined to exercise your Right of Co-Sale with respect to the Offered Units.

Election

I exercise my Right of Co-Sale	¨
I wish to sell              units.

Description of Transfer

1. Type and aggregate number of units to be transferred:

2. Type of transfer (please check one):

¨ Sale

¨ Other. Describe:

3. Proposed transferees:

Name and address		Type, amount and price of units
1.	[insert name of proposed transferee] [insert address of proposed transferee] [insert phone number of proposed transferee]	[enter amount, type and price of units]
2.	[insert name of proposed transferee] [insert address of proposed transferee] [insert phone number of proposed transferee]	[enter amount, type and price of units]

4. Consideration:

• Total cash consideration:

• Total fair market value of non-cash consideration (if any) as of the date of the notice:

• Describe any non-cash consideration in reasonable detail:

[Specify applicable return dates for the notice]. There will be no extension of this deadline.

[Enter seller’s name and address]

[Enter the company’s address and contact person]

[Attach Transfer Agreement]

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EX-2.1.7

Exhibit 2.1.7

PERSEID THERAPEUTICS LLC

VOTING AGREEMENT

September 18, 2009

TABLE OF CONTENTS

		Page
SECTION 1 VOTING		1
1.1	General	1
SECTION 2 ELECTION OF MANAGERS		1
2.1	Voting	1
2.2	Designation of Managers	2
2.3	Current Designees	2
2.4	Changes in Designees	2
2.5	Size of the Board of Managers	3
2.6	No Liability for Election of Recommended Manager	3
SECTION 3 DRAG-ALONG RIGHTS		3
3.1	Drag-Along Rights	3
SECTION 4 TERMINATION		4
4.1	Termination	4
SECTION 5 ADDITIONAL UNITS		4
5.1	Additional Units	4
SECTION 6 RESTRICTIVE LEGEND		4
6.1	Restrictive Legend	4
SECTION 7 MISCELLANEOUS		4
7.1	Certain Definitions	4
7.2	Notices	5
7.3	Governing Law	5
7.4	Successors and Assigns	5
7.5	Entire Agreement	6
7.6	Titles and Subtitles	6
7.7	Further Assurances	6
7.8	No Grant of Proxy	6
7.9	Not a Voting Trust	6
7.10	Specific Performance	6
7.11	Amendment	6
7.12	Jurisdiction; Venue	7
7.13	Attorneys’ Fees	7

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TABLE OF CONTENTS

(Continued)

		Page
7.14	Aggregation of Units	7
7.15	Severability	7
7.16	Counterparts	7
7.17	Delays or Omissions	7
7.18	Conflict	7
7.19	Jury Trial	7

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PERSEID THERAPEUTICS LLC

VOTING AGREEMENT

This Voting Agreement (this “Agreement”) is made as of September 18, 2009 by and among Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), Maxygen, Inc., a Delaware corporation (“Maxygen”), and Astellas Bio Inc., a Delaware corporation (“Bio”) (each of Bio and Maxygen an “Investor,” and collectively the “Investors”), and the persons and entities listed on Exhibit A, as amended from time to time (each a “Common Unitholder,” and collectively the “Common Unitholders”). The Investors and the Common Unitholders are also referred to herein collectively as the “Voting Parties.” All capitalized terms used and not defined herein shall have such meanings as set forth in the Master Joint Venture Agreement by and among Maxygen, Astellas Pharma Inc., and Bio dated as of June 30, 2009 (the “Joint Venture Agreement”).

RECITALS

The Company proposes to sell Series A Preferred Units and Series B Preferred Units (together, “Preferred Units”) to the Investors pursuant to the Series A and Series B Preferred Unit Purchase Agreement (the “Purchase Agreement”) of even date herewith (the “Financing”). The Company’s common units (the “Common Units”) together with the Preferred Units are referred to as the “Units.”

The Company’s LLC Agreement provides that (i) the board of managers of the Company shall consist of five members; and (ii) the holders of the Company’s Preferred Units shall be entitled to elect five managers (the “Preferred Managers”) so long as at least 6,000,000 Preferred Units (as adjusted for units dividends, units splits, combinations of units, reorganizations, recapitalizations, reclassifications or other similar events) remain outstanding.

As a condition to the Financing, the Voting Parties have agreed to enter into this Agreement.

The parties therefore agree as follows:

SECTION 1

VOTING

1.1 General. During the term of this Agreement, the Voting Parties each agree to vote all Units having voting rights under the LLC Agreement (“Voting Company Units”) now or hereafter owned by them, whether beneficially or otherwise, or as to which they have voting power in accordance with the provisions of this Agreement.

SECTION 2

ELECTION OF MANAGERS

2.1 Voting. During the term of this Agreement and so long as at least 6,000,000 Preferred Units (as adjusted for units dividends, units splits, combinations of units, reorganizations, recapitalizations, reclassifications or other similar events) remain outstanding, each Voting Party agrees to vote all Units in such manner as may be necessary to elect (and maintain in office) as members of the Company’s board of managers the following individuals:

(a) the four Majority Preferred Designees (as defined below) as four of the Preferred Managers; and

(b) the Minority Preferred Designee (as defined below) as one of the Preferred Managers.

2.2 Designation of Managers. The Preferred Managers (each a “Designee”) shall be selected as follows:

(a) The four “Majority Preferred Designees” shall be chosen by Maxygen; provided that, during such time as Bio holds more than fifty percent 50% of the outstanding Units (assuming conversion of all outstanding Preferred Units) (the “Outstanding Equity”) then the four Majority Preferred Designees shall be chosen by Bio.

(b) The one “Minority Preferred Designee” shall be chosen by Bio; provided that, during such time as Bio is entitled to choose the Majority Preferred Designees pursuant to Section 2.2(a) above, then, the one Minority Preferred Designee shall be chosen by Maxygen.

(c) Notwithstanding the foregoing, at any such time that neither Maxygen nor Bio holds greater than 50% of the Outstanding Equity, the number of Designees to be chosen by each of Maxygen and Bio shall be determined on a ratable basis, based on the number of Units of Outstanding Equity held by each such Investor, with any Designees not chosen by either Maxygen or Bio to be chosen by a majority vote of all the Outstanding Equity. For example, if Maxygen holds 45% of the Outstanding Equity and Bio holds 40% of the Outstanding Equity, then each of Maxygen and Bio shall be entitled to choose two Designees and the remaining Designee shall be chosen by a majority vote of all the Outstanding Equity.

2.3 Current Designees. For the purpose of this Agreement, the initial managers of the Company shall be the following Designees:

(a) the Majority Preferred Designees shall be Grant Yonehiro, Isaac Stein, Jim Sulat and Gordon Ringold; and

(b) the Minority Preferred Designee shall be Naoki Okamura.

2.4 Changes in Designees. From time to time during the term of this Agreement, Voting Parties who hold sufficient Units to select a Designee pursuant to this Agreement may, in their sole discretion:

(a) notify the Company in writing of an intention to remove from the Company’s board of managers any incumbent Designee who occupies a board seat for which such Voting Parties are entitled to designate the Designee; or

(b) notify the Company in writing of an intention to select a new Designee for election to a board seat for which such Voting Parties are entitled to designate the Designee (whether to replace a prior Designee or to fill a vacancy in such board seat).

In the event of such an initiation of a removal or selection of a Designee under this section, the Company shall take such reasonable actions as are necessary to facilitate such removals or elections, including, without limitation, soliciting the votes of the appropriate unitholders, and the Voting Parties shall vote their Voting Company Units to cause: (a) the removal from the Company’s board of managers of the Designee or Designees so designated for removal; and (b) the election to the Company’s board of managers of any new Designee or Designees so designated.

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2.5 Size of the Board of Managers. During the term of this Agreement, each Voting Party agrees to vote all Voting Company Units owned by it to maintain the authorized number of members of the board of managers of the Company at five managers.

2.6 No Liability for Election of Recommended Manager. None of the parties and no officer, director, stockholder, partner, employee or agent of any party makes any representation or warranty as to the fitness or competence of the nominee of any party hereunder to serve on the board of managers by virtue of such party’s execution of this Agreement or by the act of such party in voting for such nominee pursuant to this Agreement.

SECTION 3

DRAG-ALONG RIGHTS

3.1 Drag-Along Rights. From and after the expiration of the Buy-Out Option, if the Company’s Board and a majority-in-interest of the outstanding Units (determined on an as-converted basis) approve a Change of Control Transaction (as defined below in Section 4.1), each of the Voting Parties agrees (i) to vote all Voting Company Units held by such Voting Party in favor of such Change of Control Transaction, and (ii) to sell or exchange all Units then held by such Voting Party pursuant to the terms and conditions of such Change of Control Transaction, subject to the following conditions:

(a) no Voting Party shall be required to make any individual representation, covenant or warranty in connection with the Change of Control Transaction, other than as to such Voting Party’s ownership and authority to sell, free of liens, claims and encumbrances, the Units proposed to be sold by such Voting Party;

(b) the consideration payable with respect to each unit in each class or series as a result of such Change of Control Transaction shall be the same (except for cash payments in lieu of fractional units) as for each other unit in such class or series;

(c) each class of Units will be entitled to receive the same form of consideration (and be subject to the same indemnity and escrow provisions) as a result of such Change of Control Transaction, provided, that in no event shall Bio provide an indemnity or accept liability in connection with any such Change of Control Transaction that exceeds fifteen percent (15)% of the consideration actually received by it in such transaction, except that in the case of indemnity or liability with respect to representations and warranties made by a Voting Party with respect to its ownership and authority to sell the units proposed to be sold by such Voting Party, such indemnity and liability shall not exceed the total amount of consideration actually received by it in such Change of Control Transaction; and

(d) the payment with respect to each Unit is an amount at least equal to the amount payable in accordance with the LLC Agreement, if such Change of Control Transaction were deemed a Liquidity Event (as defined in the LLC Agreement).

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SECTION 4

TERMINATION

4.1 Termination. This Agreement shall terminate upon the earliest of (i) the conversion of all Preferred Units into Common Units; (ii) a Change of Control Transaction; (iii) (A) with respect to Sections 2.1 through 2.6, the later of the expiration of the Buy-Out Option or, if such option is not exercised and Bio extends credit to the Company pursuant to the Loan Agreement (as described in the Investors’ Rights Agreement), such time when no amount is owed by the Company under such Loan Agreement and (B) with respect to Section 3.1, consummation of the transaction resulting from the exercise Buy-Out Option; or (iv) the agreement of each of the Investors. “Change of Control Transaction” means either (a) the acquisition of the Company by another entity by means of any transaction or series of related transactions to which the Company is party (including, without limitation, any unit acquisition, reorganization, merger or consolidation) that results in the voting securities of the Company outstanding immediately prior thereto failing to represent immediately after such transaction or series of transactions (either by remaining outstanding or by being converted into voting securities of the surviving entity or the entity that controls such surviving entity) a majority of the total voting power represented by the outstanding voting securities of the Company, such surviving entity or the entity that controls such surviving entity, excluding, in each case, any bona fide sale of units for capital raising purposes; or (b) a sale, lease, exclusive license or other conveyance of all or substantially all of the assets of the Company.

SECTION 5

ADDITIONAL UNITS

5.1 Additional Units. In the event that subsequent to the date of this Agreement any units or other securities (other than pursuant to a Change of Control Transaction) are issued on, or in exchange for, any of the Units by reason of any units dividend, units split, consolidation of units, reclassification or consolidation involving the Company, such units or securities shall be deemed to be Units for purposes of this Agreement.

SECTION 6

RESTRICTIVE LEGEND

6.1 Restrictive Legend. Each certificate representing any of the Units subject to this Agreement shall be marked by the Company with the legend appearing in Section 3.8 of the Purchase Agreement.

SECTION 7

MISCELLANEOUS

7.1 Certain Definitions. Units “held” by a Voting Party shall mean any units directly or indirectly owned (of record or beneficially) by such Voting Party or as to which such Voting Party has voting power. “Vote” shall include any exercise of voting rights whether at an annual or special meeting or by written consent or in any other manner permitted by applicable law. A “majority-in-interest” of either the Common Unitholders or the Investors shall mean the holders of a majority of the Common Units (determined on an as-converted basis) then held by such group.

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7.2 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent electronic mail or otherwise delivered by hand, messenger or courier service addressed:

(a) if to Maxygen, to the address or electronic mail address of Maxygen as set forth in Exhibit B, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: David J. Segre and Tony Jeffries;

(b) if to Bio, to the address or electronic mail address of Bio as set forth in Exhibit B, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Morrison & Foerster LLP, 1290 Avenue of the Americas, New York, New York 10104, Attention: Michael Braun;

(c) if to any Voting Party not provided for in paragraphs (a) or (b), above, to such address or electronic mail address as shown in the Company’s records, or, until any such Voting Party so furnishes an address to the Company, then to the address of the last holder of such units for which the Company has contact information in its records; or

(d) if to the Company, to the attention of the Chief Executive Officer or Chief Financial Officer of the Company at 515 Galveston Drive, Redwood City, CA 94063, as may be updated in accordance with the provisions hereof, with a copy (which shall not constitute notice) to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill Road, Palo Alto, California 94304, Attention: David J. Segre and Tony Jeffries.

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given (i) if delivered by hand, messenger or courier service, when delivered (or if sent via a nationally-recognized overnight courier service, freight prepaid, specifying next-business-day delivery, two (2) Business Days after deposit with the courier), (ii) if sent via registered or certified mail, at the earlier of its receipt or five (5) days after the same has been deposited in a regularly-maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid, or (iii) if sent via electronic mail, when directed to the relevant electronic mail address, if sent during normal business hours of the recipient, or if not sent during normal business hours of the recipient, then on the recipient’s next Business Day and in either case later confirmed in writing.

Each Voting Party consents to the delivery of any notice to members given by the Company under the Delaware Limited Liability Company Act or the Certificate or the LLC Agreement by (i) electronic mail to the electronic mail address set forth above (or to any other electronic mail address for the Voting Party in the Company’s records), (ii) posting on an electronic network together with separate notice to the Voting Party of such specific posting or (iii) any other form of electronic transmission (as defined in §18-302 of the Delaware Limited Liability Company Act) directed to the Voting Party. This consent may be revoked by a Voting Party by written notice to the Company and may be deemed revoked in the circumstances specified in the LLC Agreement.

7.3 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of Delaware as applied to agreements entered into among Delaware residents to be performed entirely within Delaware, without regard to principles of conflicts of law.

7.4 Successors and Assigns. Except as provided in this Section 7.4, this Agreement shall not be assignable or otherwise transferred, in whole or in part, by the Company or any Voting Party to any third

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party without the written consent of the other parties hereto, provided that this Agreement may without requiring the consent of the other parties be assigned, transferred, delegated or sublicensed in connection with the transfer of Units to (a) an entity that acquires all or substantially all of the business or assets of such party, whether by merger, reorganization, acquisition, asset sale or otherwise, or (b) any Related Entity (as defined in the Investors’ Rights Agreement) of such party, in each case subject to the agreement in writing of such transferee to be subject to the terms and conditions of this Agreement and, prior to the Option Expiration Date (as defined in the Investors’ Rights Agreement), the Investors’ Rights Agreement, the Co-Sale Agreement and the LLC Agreement. The terms and conditions of this Agreement shall be binding on and inure to the benefit of the permitted successors and assigns of the parties. Except as expressly provided in this Section 7.4, any attempted assignment or transfer of this Agreement shall be null and void.

7.5 Entire Agreement. This Agreement and the exhibits hereto and the Transaction Agreements constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof and thereof. No party hereto shall be liable or bound to any other party in any manner with regard to the subjects hereof or thereof by any warranties, representations or covenants except as specifically set forth herein or therein.

7.6 Titles and Subtitles. The titles and subtitles used in this Agreement are used for convenience only and are not to be considered in construing or interpreting this Agreement. All references in this Agreement to sections, paragraphs and exhibits shall, unless otherwise provided, refer to sections and paragraphs hereof and exhibits attached hereto.

7.7 Further Assurances. Each party hereto agrees to execute and deliver, by the proper exercise of its corporate, limited liability company, partnership or other powers, all such other and additional instruments and documents and do all such other acts and things as may be necessary to more fully effectuate this Agreement.

7.8 No Grant of Proxy. This Agreement does not grant any proxy and should not be interpreted as doing so. Nevertheless, should the provisions of this Agreement be construed to constitute the granting of proxies, such proxies shall be deemed coupled with an interest and are irrevocable for the term of this Agreement.

7.9 Not a Voting Trust. This Agreement is not a voting trust governed by Section 706(b) of the California Corporations Code or 218 of the Delaware General Corporation Law and should not be interpreted as such.

7.10 Specific Performance. It is agreed and understood that monetary damages would not adequately compensate an injured party for the breach of this Agreement by any party, that this Agreement shall be specifically enforceable, and that any breach or threatened breach of this Agreement shall be the proper subject of a temporary or permanent injunction or restraining order. Further, each party waives any claim or defense that there is an adequate remedy at law for such breach or threatened breach.

7.11 Amendment. Except as expressly provided herein, neither this Agreement nor any term hereof may be amended, waived, discharged or terminated other than by a written instrument referencing this Agreement and signed by (i) the Company and (ii) each Investor. Any such amendment, waiver, discharge or termination effected in accordance with this paragraph shall be binding upon each Voting Party that has entered into this voting agreement. Each Voting Party acknowledges that by the operation of this paragraph, the Investors will have the right and power to diminish or eliminate all rights of such Voting Party under this Agreement.

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7.12 Jurisdiction; Venue. With respect to any disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, any court in the State of Delaware having subject matter jurisdiction (or in the event of exclusive federal jurisdiction, the courts of the District of Delaware).

7.13 Attorneys’ Fees. In the event that any suit or action is instituted to enforce any provision in this Agreement, the prevailing party in such dispute shall be entitled to recover from the losing party such reasonable fees and expenses of attorneys and accountants, which shall include, without limitation, all fees, costs and expenses of appeals.

7.14 Aggregation of Units. All securities held or acquired by affiliated entities or persons shall be aggregated together for purposes of determining the availability of any rights under this Agreement, including, without limitation, the rights with respect to Designees under SECTION 2. For the avoidance of doubt, none of the Company, Maxygen or Bio shall be considered to be “affiliated entities” of one another for the purposes of this Agreement.

7.15 Severability. If any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Agreement, and such court will replace such illegal, void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Agreement shall be enforceable in accordance with its terms.

7.16 Counterparts. This Agreement may be executed and delivered by PDF signature and in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

7.17 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party to this Agreement upon any breach or default of any other party under this Agreement shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any kind or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party to this Agreement, shall be cumulative and not alternative.

7.18 Conflict. In the event of any conflict between the terms of this Agreement and the Certificate or LLC Agreement, the terms of the Certificate or LLC Agreement as the case may be, will control. In the event of any conflict between the terms of this Agreement and any other agreement to which an Investor is a party or by which such Investor is bound, the terms of this Agreement will control. In the event of any conflict between the Company’s books and records and this Agreement or any notice delivered hereunder, the Company’s books and records will control absent fraud or error.

7.19 Jury Trial. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING (WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATED TO THIS AGREEMENT. This paragraph shall not restrict a party from exercising remedies under the Uniform Commercial Code or from exercising pre-judgment remedies under applicable law.

(signature page follows)

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The parties are signing this Voting Agreement as of the date stated in the introductory clause.

PERSEID THERAPEUTICS LLC
a Delaware limited liability company
By:	/s/    Grant Yonehiro
Name:	Grant Yonehiro
Title:	Chief Executive Officer and President

[SIGNATURE PAGE TO THE VOTING AGREEMENT]

The parties are signing this Voting Agreement as of the date stated in the introductory clause.

INVESTOR
Astellas Bio Inc.
By:	/s/    Kazunori Okimura
Name:	Kazunori Okimura
Title:	Secretary

[SIGNATURE PAGE TO THE VOTING AGREEMENT]

The parties are signing this Voting Agreement as of the date stated in the introductory clause.

INVESTOR
Maxygen, Inc.
By:	/s/    Russell J. Howard
Name:	Russell J. Howard, Ph.D.
Title:	Chief Executive Officer

[SIGNATURE PAGE TO THE VOTING AGREEMENT]

Exhibit A

COMMON UNITHOLDERS

None.

Exhibit B

INVESTORS

Astellas Bio Inc.

Three Parkway

North Deerfield, IL 60015-2458

Email: masaki.doi@jp.astellas.com and kazunori.okimura@jp.astellas.com

Maxygen, Inc.

515 Galveston Drive

Redwood City, CA 94063

Email: corporatesecretary@maxygen.com

EX-10.5

Exhibit 10.5

PERSEID THERAPEUTICS LLC

2009 EQUITY INCENTIVE PLAN

1. Purposes of the Plan. The purposes of this Plan are to attract and retain the best available personnel for positions of substantial responsibility, to provide additional incentive to Employees, Directors, Members and Consultants, and to promote the success of the Company’s business by the grant of Common Units in the Company as Profits Interest Units.

2. Definitions. As used herein, the following definitions will apply:

(a) “Administrator” means the Board of Managers or any of its Committees as will be administering the Plan, in accordance with Section 4 of the Plan.

(b) “Applicable Laws” means the requirements relating to the administration of equity-based awards under U.S. state corporation laws, U.S. federal and state securities laws, the Code, and the applicable law of any foreign country or jurisdiction where Awards are, or will be, granted under the Plan.

(c) “Award” means, individually or collectively, a grant under the Plan of Common Units as Profits Interest Units.

(d) “Award Agreement” means the written or electronic agreement setting forth the terms and provisions applicable to each Award granted under the Plan. The Award Agreement is subject to the terms and conditions of the Plan.

(e) “Board” means the Board of Managers of the Company.

(f) “Buy-Out Units” has the meaning defined in the Investors’ Rights Agreement.

(g) “Cause” means (i) willful and continued failure to substantially perform the Service Provider’s duties with the Company (other than as a result of the Service Provider’s Disability) after a written demand for substantial performance is delivered to the Service Provider by the Company, which demand specifically identifies the manner in which the Company believes that the Service Provider has not substantially performed the Service Provider’s duties and that has not been cured within fifteen (15) days following receipt by the Service Provider of the written demand; (ii) commission of a felony (other than a traffic-related offense) that in the written determination of the Company is likely to cause or has caused material injury to the Company’s business; (iii) dishonesty with respect to a significant matter relating to the Company’s business; or (iv) material breach of any agreement by and between the Service Provider and the Company, which material breach has not been cured within fifteen (15) days following receipt by the Service Provider of written notice from the Company identifying such material breach.

(h) “Buy-Out Option” has the meaning defined in the Investors’ Rights Agreement.

(i) “Code” means the Internal Revenue Code of 1986, as amended. Any reference to a section of the Code herein will be a reference to any successor or amended section of the Code.

(j) “Committee” means a committee of the Board.

(k) “Common Unit” has the meaning defined in the Operating Agreement.

(l) “Company” means Perseid Therapeutics LLC, a Delaware limited liability company, or any successor thereto.

(m) “Consultant” means any person, including an advisor, who is engaged by the Company or a Parent or Subsidiary to render services to such entity, including service providers who are employees of entities engaged to provide such services.

(n) “Conversion” means the conversion of the legal form of the Company to a corporation.

(o) “Director” means a member of the Board.

(p) “Disability” means total and permanent disability as defined in Code Section 22(e)(3).

(q) “Distribution Threshold” has the meaning defined in the Operating Agreement.

(r) “Employee” means any person, including officers and Directors, employed by the Company or any Parent or Subsidiary of the Company.

(s) “Exercise Price” has the meaning defined in the Investors’ Rights Agreement.

(t) “Fair Market Value” of a Profits Interest Unit means (i) as of any date prior to the expiration of the Buy-Out Option, (x) the value of Common Units derived from the deemed value of the Company in light of the applicable Exercise Price for the Buy-Out Units, the then fully-diluted capitalization of the Company, and the then liquidation preferences, participation rights and other terms and conditions of the Company’s Units less (y) the applicable Distribution Threshold for the Profits Interest Units and, (ii) as of the expiration of the Buy-Out Option and any date following such expiration, (x) the fair market value of the Common Units determined in good faith by the Administrator less (y) the applicable Distribution Threshold for the Profits Interest Units. Assuming there is no change to the initial structure and capitalization of the Company and assuming there are no unpaid dividends, the value of a Common Unit upon the exercise of the Buy-Out Option shall be equal the per unit exercise price of the Buy-Out Units less the liquidation preference of such unit.

(u) “Good Reason” means: (i) a reduction by the Company in the base compensation of the Service Provider of ten percent (10%) or more, except if agreed to in writing by the Service Provider; or (ii) the relocation of the Service Provider to a facility or a location more than thirty (30) miles from the Service Provider’s then present business location, except if agreed to in writing by the Service Provider; provided, however, that such events shall not constitute grounds

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for a Good Reason termination unless the Service Provider has provided notice to the Company of the existence of the one or more of the above conditions within ninety (90) days of its initial existence and the Company has been provided at least thirty (30) days to remedy the condition.

(v) “Investors’ Rights Agreement” shall mean that certain Investors’ Rights Agreement by and among the Company, Maxygen, Inc. and Astellas Pharma Inc.

(w) “Joint Venture Agreement” means that certain Master Joint Venture Agreement entered into by the Maxygen, Inc., Astellas Pharma Inc. and Astellas Bio Inc.

(x) “Liquidity Event” has the meaning defined in the Operating Agreement.

(y) “Operating Agreement” means the Limited Liability Company Agreement of Perseid Therapeutics LLC, as amended from time to time.

(z) “Member” means any Member of the Company, as defined in the Operating Agreement, who is providing services.

(aa) “Parent” means a “parent corporation,” whether now or hereafter existing, as defined in Code Section 424(e).

(bb) “Participant” means the holder of an outstanding Award.

(cc) “Plan” means this 2009 Equity Incentive Plan.

(dd) “Profits Interest Units” shall mean a Common Unit granted as a “profits interest” unit pursuant the Operating Agreement and the Plan.

(ee) “Service Provider” means an Employee, Member, Director or Consultant.

(ff) “Securities Act” means the Securities Act of 1933, as amended.

(gg) “Subsidiary” means a “subsidiary corporation,” whether now or hereafter existing, as defined in Code Section 424(f).

(hh) “Voting Agreement” means the Voting Agreement dated as of September 18, 2009, by and among the Company, Maxygen, Inc. and Astellas Bio Inc.

3. Units Subject to the Plan.

(a) Units Subject to the Plan. Subject to the provisions of Section 11 of the Plan, the maximum aggregate number of Common Units that may be subject to Awards and granted under the Plan is 15,000,000 Common Units. The Common Units may be authorized but unissued, or reacquired, Common Units.

(b) Lapsed Awards. If an Award is forfeited to the Company due to failure to vest or is repurchased by the Company, Common Units which were subject thereto will become available for future grant under the Plan (unless the Plan has terminated).

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(c) Unit Reserve. The Company, during the term of this Plan, will at all times reserve and keep available such number of Common Units as will be sufficient to satisfy the requirements of the Plan.

4. Administration of the Plan.

(a) Procedure. The Plan will be administered by (A) the Board or (B) a Committee, which Committee will be constituted to satisfy Applicable Laws. To the extent that any such Committee does not include the Minority Preferred Designee (as defined in the Voting Agreement), then the Minority Preferred Designee shall be entitled to attend in a non-voting, observer capacity all meetings of such Committee and to receive all notices and other communications (including, without limitation, Actions by Written Consent Without a Meeting) that are sent to members of such Committee in their capacity as such. Prior to the expiration of the Buy-Out Option, the vote of the Minority Preferred Designee shall be required for any amendment to the Plan.

(b) Powers of the Administrator. Subject to the provisions of the Plan, and in the case of a Committee, subject to the specific duties delegated by the Board to such Committee, the Administrator will have the authority, in its discretion:

(i) to select the Service Providers to whom Awards may be granted hereunder;

(ii) to determine the number of Common Units to be covered by each Award granted hereunder;

(iii) to approve forms of Award Agreements for use under the Plan;

(iv) to determine the terms and conditions, not inconsistent with the terms of the Plan, of any Award granted hereunder. Such terms and conditions include, but are not limited to the time or times when Awards may vest (which may be based on performance criteria), any vesting acceleration or waiver of forfeiture restrictions, and any restriction or limitation regarding any Award or the Common Units relating thereto, based in each case on such factors as the Administrator will determine;

(v) to construe and interpret the terms of the Plan and Awards granted pursuant to the Plan;

(vi) to prescribe, amend and rescind rules and regulations relating to the Plan, including rules and regulations relating to sub-plans established for the purpose of satisfying applicable foreign laws or for qualifying for favorable tax treatment under applicable foreign laws;

(vii) to modify or amend each Award (subject to Section 17(c) of the Plan);

(viii) to repurchase Profits Interest Units pursuant to Section 6(c);

(ix) to authorize any person to execute on behalf of the Company any instrument required to effect the grant of an Award previously granted by the Administrator;

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(x) to allow a Participant to defer the receipt of the payment of cash or the delivery of property that otherwise would be due to such Participant under an Award; and

(xi) to make all other determinations deemed necessary or advisable for administering the Plan.

(c) Effect of Administrator’s Decision. The Administrator’s decisions, determinations and interpretations will be final and binding on all Participants and any other holders of Awards.

5. Eligibility. Awards may be granted only to Service Providers.

6. Profits Interest Units.

(a) Profits Interest Agreement. Subject to the terms of the Plan and the Operating Agreement, the Administrator may grant Profits Interest Units in such amounts as the Administrator, in its sole discretion, will determine. Each Profits Interest grant will be evidenced by a Profits Interest Agreement that will specify the number of Common Units that are being granted as Profits Interest Units, the Distribution Threshold, the vesting schedule, if any, applicable to the Profits Interest grant, and such other terms and conditions as the Administrator, in its sole discretion, will determine.

(b) Forfeiture. If a Participant’s status as a Service Provider is terminated for any reason by the Participant or the Company before the Profits Interest Units have vested, unless otherwise determined by the Administrator or unless otherwise provided in the Profits Interest Agreement, the Participant will forfeit all non-vested Profits Interest Units to the Company for no consideration without further action by the Company.

(c) Repurchase Provision. The Administrator shall have the right to repurchase any Participant’s Profits Interest Units at any time (including during such time as a Participant is no longer a Service Provider) for a payment in cash at a price per Unit equal to the per-Profits Interest Unit Fair Market Value.

(d) Rights as a Member. Each Participant granted a Profits Interest Award shall agree to be bound by and comply with the terms of the Operating Agreement and shall become a party to the Operating Agreement upon executing a Profits Interest Award Agreement. No certificate representing the Profits Interest Unit will be issued, and the Profits Interest Unit shall have no voting or other rights other than as expressly set forth herein, in the applicable Award Agreement or in the Operating Agreement.

(e) Payment. Unless otherwise determined by the Administrator, no amount shall be paid to the Company for the grant of Profits Interest Units.

(f) Distributions. A Participant shall be entitled to distributions with respect to a Profits Interest only as provided in the Operating Agreement (if at all).

7. Conversion. Subject to the provisions of the merger, reorganization or other agreement setting forth the terms of a direct exchange, merger or other reorganization transaction,

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and subject to the Operating Agreement, upon a Conversion, all Awards granted under the Plan shall be exchanged for or converted into shares of the resulting corporation’s common stock, stock options or other equity-based awards, in each case with terms substantially equivalent to the terms of the Awards they are intended to replace.

8. Compliance With Code Section 409A. Each Award under the Plan is intended to be exempt from Code Section 409A pursuant to IRS Notice 2005-1, Q&A 7, and will be construed and interpreted in accordance with such intent, except as otherwise determined in the sole discretion of the Administrator.

9. Leaves of Absence/Transfer Between Locations. Unless the Administrator provides otherwise, vesting of Awards granted hereunder will be suspended during any unpaid leave of absence. A Participant will not cease to be a Service Provider in the case of (i) any leave of absence approved by the Company or (ii) transfers between locations of the Company or between the Company and any Subsidiary. No such leave may exceed three (3) months, unless reemployment upon expiration of such leave is guaranteed by statute or contract.

10. Limited Transferability of Awards. Awards granted under the Plan shall be subject to the terms and conditions of the Operating Agreement and any special forfeiture conditions, rights of repurchase, rights of first refusal or other transfer restrictions as determined by the Board. Unless determined otherwise by the Administrator, Awards may not be sold, pledged, assigned, hypothecated, or otherwise transferred in any manner other than by will or by the laws of descent and distribution. If the Administrator makes an Award transferable, such Award may only be transferred (i) by will, (ii) by the laws of descent and distribution, or (iii) as permitted by Rule 701 of the Securities Act.

11. Adjustments; Liquidity Event.

(a) Adjustments. In the event that any recapitalization, reorganization, merger, split-up, spin-off, subdivision or combination of Common Units, repurchase, or exchange of Common Units or other securities of the Company, or other change in the capital structure of the Company affecting the Common Units occurs, the Administrator, in order to prevent diminution or enlargement of the benefits or potential benefits intended to be made available under the Plan, will adjust the number and class of Common Units that may be delivered under the Plan and/or the number, class, and Distribution Threshold of Common Units covered by each outstanding Award.

(b) Liquidity Event. In the event of a Liquidity Event (other than a Liquidity Event resulting from the exercise of the Buy-Out Option, which shall be provided for under Section 12), each outstanding Award will be subject to the Operating Agreement and to the agreement governing the Liquidity Event. The agreement governing the Liquidity Event shall provide for one more of the following: (i) Awards will be assumed, or substantially equivalent Awards will be substituted, by the acquiring or succeeding corporation (or an affiliate thereof) with appropriate adjustments as to the number and kind of equity and prices; (ii) outstanding Awards will vest and become exercisable, realizable, or payable, or restrictions applicable to an Award will lapse, in whole or in part prior to or upon consummation of such Liquidity Event; (iii) outstanding Awards will (A) terminate in exchange for an amount of cash and/or property, if any, equal to the per- Profits Interest Unit Fair Market Value multiplied by the number of vested Common Units underlying the

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Award (and, for the avoidance of doubt, if as of the date of the occurrence of the transaction the Administrator determines in good faith that no amount would have been payable with respect to a Common Unit under the Operating Agreement, then such Award may be terminated by the Company without payment), or (B) be replaced with other rights or property selected by the Administrator in its sole discretion; or (iv) any combination of the foregoing. In taking any of the actions permitted under this subsection 11(b), the Administrator will not be obligated to treat all Awards, all Awards held by a Participant, or all Awards of the same type, similarly. Notwithstanding anything in this Section 11(b) to the contrary, if a payment under an Award Agreement is subject to Code Section 409A and if the change in control definition contained in the Award Agreement does not comply with the definition of “change of control” for purposes of a distribution under Code Section 409A, then any payment of an amount that is otherwise accelerated under this Section will be delayed until the earliest time that such payment would be permissible under Code Section 409A without triggering any penalties applicable under Code Section 409A.

12. Exercise of Buy-Out Option. Upon the consummation of a Liquidity Event resulting from the exercise of the Buy-Out Option (the “Option Closing”), (a) all outstanding vested Awards shall terminate in exchange for a cash payment for each vested Unit equal to the per-Profits Interest Unit Fair Market Value; and (b) all outstanding unvested Awards shall have their remaining vesting schedules automatically amended so as to vest 100% on the earliest of the following dates: (A) the six-month anniversary of the Option Closing, subject to the holder remaining a Service Provider through such new vesting date; (B) the involuntary termination of the Service Provider without Cause, other than due to death or Disability, (C) the voluntary termination of the Service Provider for Good Reason, or (D) such earlier time as is specified by the Administrator in its sole discretion, at which time Awards that vest shall terminate in exchange for a cash payment for each Unit equal to the per-Profits Interest Unit Fair Market Value. Unvested Awards subject to the previous sentence will not vest if, prior to the six-month anniversary of the Option Closing, the Participant voluntarily terminates as a Service Provider without Good Reason or is terminated for Cause and such Awards will be forfeited to the Company for no consideration without further action by the Company upon such termination. Prior to the earlier of the consummation of a Liquidity Event (including a Liquidity Event resulting from the exercise of the Buy-Out Option) or their repurchase pursuant to Section 6(c), the Profits Interest Units shall not be entitled to receipt of any payment pursuant to the terms of this Plan.

Example: The Buy-Out Option is exercised on the 2-year anniversary of the closing of the transactions establishing the Company (the “Closing”), and the holders of Perseid Therapeutics LLC Common Units receive $0.62 per Unit. Employee Alpha was granted 40,000 Common Units as Profits Interest Units on the Closing, (the “Alpha Units”) with a $0.06 per Unit Distribution Threshold. The Alpha Units had an original vesting schedule where 25% of the Alpha Units vested on the first anniversary of the grant date, and 1/48^th of the Alpha Units granted vested each month thereafter, so as to be 100% vested on the fourth anniversary of the Alpha Units grant date, subject to the Service Provider remaining as such through each vesting date. Accordingly, the Alpha Units are 50% vested on the date the Buy-Out Option is exercised. At this time, Employee Alpha receives $11,200 in respect of the vested Alpha Units (20,000 times the per-Profits Interest Unit Fair Market Value, which is $0.56 ($0.62 minus the $0.06 Distribution Threshold)). The unvested Alpha Units have their remaining vesting schedule automatically adjusted so the Common Units vest upon the first to occur of: (A) the six-month anniversary of the Option Closing, subject to the holder remaining a Service Provider through such new vesting date; (B) the involuntary termination of the

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Service Provider without Cause, other than due to death or Disability, (C) the voluntary termination of the Service Provider for Good Reason, or (D) such earlier time as is specified by the Administrator in its sole discretion. Assuming Employee Alpha remained employed through the six-month anniversary of the Option Closing, then the remaining Alpha Units will vest and Employee Alpha will receive a payment equal to the amount payable for such Units under the Buy-Out Option of $11,200 (20,000 times the per-Profits Interest Unit Fair Market Value of $0.56). The foregoing example assumes no change to the initial structure and capitalization of the Company and assumes there are no unpaid dividends.

13. Tax Withholding. Prior to the delivery of any Common Units or cash pursuant to an Award (or vesting thereof), the Company will have the power and the right to deduct or withhold, or require a Participant to remit to the Company, an amount sufficient to satisfy federal, state, local, foreign or other taxes (including the Participant’s FICA obligation) required to be withheld with respect to such Award (or exercise thereof).

14. No Effect on Employment or Service. Neither the Plan nor any Award will confer upon a Participant any right with respect to continuing the Participant’s relationship as a Service Provider with the Company, nor will they interfere in any way with the Participant’s right or the Company’s right to terminate such relationship at any time, with or without cause, to the extent permitted by Applicable Laws.

15. Date of Grant. The date of grant of an Award will be, for all purposes, the date on which the Administrator makes the determination granting such Award, or such other later date as is determined by the Administrator. Notice of the determination will be provided to each Participant within a reasonable time after the date of such grant.

16. Term of Plan. Subject to Section 20 of the Plan, the Plan will become effective upon its adoption by the Board. Unless sooner terminated under Section 17, it will continue in effect for a term of ten (10) years from the later of (a) the effective date of the Plan, or (b) the earlier of the most recent Board or Member approval of an increase in the number of Common Units reserved for issuance under the Plan.

17. Amendment and Termination of the Plan.

(a) Amendment and Termination. The Board may at any time amend, alter, suspend or terminate the Plan; provided that, prior to the expiration of the Buy-Out Option, the approval of the Minority Preferred Designee shall be required to for any amendment to the Plan.

(b) Member Approval. The Company will obtain Member approval of any Plan amendment to the extent necessary and desirable to comply with Applicable Laws.

(c) Effect of Amendment or Termination. No amendment, alteration, suspension or termination of the Plan will impair the rights of any Participant, unless mutually agreed otherwise between the Participant and the Administrator, which agreement must be in writing and signed by the Participant and the Company. Termination of the Plan will not affect the Administrator’s ability to exercise the powers granted to it hereunder with respect to Awards granted under the Plan prior to the date of such termination.

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18. Conditions Upon Issuance of Common Units.

(a) Legal Compliance. Common Units will not be issued pursuant to the exercise of an Award unless the exercise of such Award and the issuance and delivery of such Common Units will comply with Applicable Laws and will be further subject to the approval of counsel for the Company with respect to such compliance.

(b) Investment Representations. As a condition to the receipt of an Award, the Company may require the person exercising such Award to represent and warrant that Common Units are being purchased only for investment and without any present intention to sell or distribute such Common Units if, in the opinion of counsel for the Company, such a representation is required.

19. Inability to Obtain Authority. The inability of the Company to obtain authority from any regulatory body having jurisdiction, which authority is deemed by the Company’s counsel to be necessary to the lawful issuance or sale of any Common Units Shares hereunder, will relieve the Company of any liability in respect of the failure to issue or sell such Common Units as to which such requisite authority will not have been obtained.

20. Member Approval. The Plan will be subject to approval by the Members of the Company within twelve (12) months after the date the Plan is adopted by the Board. Such Member approval will be obtained in the manner and to the degree required under Applicable Laws.

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PERSEID THERAPEUTICS LLC 2009 EQUITY INCENTIVE PLAN

NOTICE OF PROFITS INTEREST UNIT GRANT

You have been granted Profits Interest Units of Perseid Therapeutics LLC (“Perseid” or “Company”) as consideration for the provision of services to or for the benefit of Perseid pursuant to the terms of the attached Profits Interest Unit Agreement. A Profits Interest Unit is a special type of Company Common Unit that allows you to potentially participate in a future increase in the value of Perseid. The principal terms of the grant are as follows:

Name of Grantee:

Total Number of Profits Interests Units:

Distribution Threshold per Unit:

Date of Grant:

Vesting Commencement Date:

Vesting Schedule:

The potential value of your Profits Interest Unit, to the extent vested, is equal to the fair market value of the Profits Interest Unit at the time of a Liquidity Event, such as a buy-out of Maxygen’s equity interest in Perseid by Astellas or the sale of Perseid to another company. The Fair Market Value is calculated as being equal to (x) the deemed value of a Common Unit at the time of the Liquidity Event less (y) the deemed value of a Common Unit at the time the Profits Interest Unit was granted (aka, the “Distribution Threshold”).

The Administrator of the Perseid Therapeutics LLC 2009 Equity Incentive Plan (the Board of Managers of Perseid) determined the Distribution Threshold and will determine the value of the Common Unit at the time of the Liquidity Event. Subject to changes in Perseid’s structure and/or capitalization, the value of a Common Unit at the time of a buy-out Maxygen’s equity interest in Perseid by Astellas is expected to be equal to the value of a Series A Preferred Unit (the type of Unit held by Maxygen) less its $1.00 per unit liquidation preference.

For example, and again assuming no changes in initial Perseid structure or capitalization and assuming there are no unpaid dividends, if Astellas buys-out Maxygen’s Series A units at a price of $1.62 per share the deemed value of a Common Unit would be $0.62 per share. The holder of a Profits Interest Units with a Distribution Threshold of $0.06 would receive $0.56 per Profits Interest Unit.

By your signature and the signature of Perseid’s representative on the Profits Interest Unit Agreement, you and Perseid agree that the Profits Interest Units are granted under and governed by the terms and conditions of your particular Profits Interest Unit Agreement, the Perseid Therapeutics 2009 Equity Incentive Plan and the Perseid LLC Agreement (the “Operating Agreement”), each of which are attached to and made a part of this document.

THE PROFITS INTEREST UNITS GRANTED PURSUANT TO THIS AGREEMENT HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED, OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT OR AN OPINION OF COUNSEL, SATISFACTORY TO THE COMPANY AND ITS COUNSEL, THAT SUCH REGISTRATION IS NOT REQUIRED. THE GRANTEE HEREBY AGREES THAT ALL COMMON UNITS ACQUIRED PURSUANT TO THIS AGREEMENT SHALL BE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AS SET FORTH IN THE OPERATING AGREEMENT.

PERSEID THERAPEUTICS LLC 2009 EQUITY INCENTIVE PLAN:

PROFITS INTEREST UNIT AGREEMENT

THIS PROFITS INTEREST UNIT AGREEMENT (the “Agreement”) is entered into as of             , 200  , by Perseid Therapeutics LLC, a Delaware limited liability company (the “Company”), and                                 (the “Grantee”).

SECTION 1. Grant of Profits Interest Units.

(a) Profits Interest Units. On the terms and conditions set forth in the Notice of Profits Interest Unit Grant and this Agreement, the Company grants to the Grantee on the Date of Grant the number of Common Units issued as Profits Interest Units (the “Profits Interest Units”) set forth in the Notice of Profits Interest Unit Grant. The Profits Interest Units granted under this Agreement are intended to meet the definition of a “profits interest” in I.R.S. Revenue Procedure 93-27 and with I.R.S. Revenue Procedure 2001-43. Accordingly, at the time the Profits Interest Units are granted, such Profits Interest Units will not give the Grantee a share of the proceeds if the Company’s assets were sold at fair market value and the proceeds of such disposition were distributed in complete liquidation of the Company, but give the holder a right to share in the appreciation in the value of the Company from the date of receipt forward.

(b) Profits Interest Distribution Threshold. The Profits Interest Distribution Threshold per Profits Interest Unit shall be the amount set forth in the Notice of Profits Interest Unit Grant.

(c) Member or Assignee of the Company. Upon the Date of Grant set forth in the Notice of Profits Interest Unit Grant, the Grantee shall be admitted as a Member of the Company, subject to the terms of the Operating Agreement.

(d) Plan and Operating Agreement. The Profits Interest Units are granted pursuant to the Plan and pursuant to the Operating Agreement, a copy of each of which the Grantee acknowledges having received. The provisions of the Plan are incorporated into this Agreement by this reference. Subject to Section 17(c) of the Plan, in the event of any conflict between the terms of the Plan and this Agreement, the Plan shall prevail. As a condition of grant of the Profits Interest Unit and upon signing this Agreement the Grantee shall become a party to the Operating Agreement

for all purposes. Grantee acknowledges that he or she (i) has read the Operating Agreement, the Plan and this Agreement, (ii) accepts and agrees to be bound by the terms of the Operating Agreement, the Plan and this Agreement, and (iii) assumes all of the rights and obligations of a Member of the Company. The Schedule A of the Operating Agreement shall be amended to reflect (i) the grant of Profits Interest Units to the Grantee under this Agreement and (ii) any forfeiture of Profits Interest Units by the Grantee.

(e) Withholding Taxes. The Grantee shall make such arrangements as the Managers may require for the satisfaction of any federal, state, local or foreign withholding tax obligations that may arise in connection with the grant of Profits Interest Units under this Agreement or distributions with respect to such Profits Interest Units. The Grantee shall also make such arrangements as the Board of Managers may require for the satisfaction of any federal, state, local or foreign withholding tax obligations that may arise in connection with the disposition of the Profits Interest Units.

(f) Defined Terms. Unless otherwise defined herein (including in Section 13 of this Agreement), the terms defined in the Plan shall have the same defined meanings in this Agreement.

SECTION 2. Forfeiture of Profits Interest Units.

(a) Surrender. Until the Profits Interest Units vest in accordance with Subsection (b) below, all non-vested Profits Interest Units shall be “Restricted Units.” Upon the termination of Service of the Grantee, the Grantee’s Restricted Units shall be surrendered to the Company without payment of consideration therefore. The Company, however, may elect to allow the Grantee to retain all or a portion of the Restricted Units.

(b) Vesting. The Profits Interest Units shall vest and shall become “Vested Units” as provided in the Vesting Schedule of the Notice of Profits Interest Unit Grant.

(c) Escrow. Upon issuance, the certificate(s) (if any) for Restricted Units shall be deposited in escrow with the Company to be held in accordance with the provisions of this Agreement. Any additional or exchanged securities or other property described in Subsection (f) below shall immediately be delivered to the Company to be held in escrow. All ordinary cash distributions on Restricted Units (or on other securities held in escrow) shall be paid directly to the Grantee and shall not be held in escrow. Restricted Units, together with any other assets held in escrow under this Agreement, shall be (i) surrendered to the Company upon forfeiture of such Restricted Units or (ii) released to the Grantee upon his or her request to the extent that the Profits Interest Units have become Vested Units (but not more frequently than once every six months). In any event, all Vested Units, together with any other vested assets held in escrow under this Agreement, shall be released within 90 days after the earlier of (i) the termination of the Grantee’s Service or (ii) the Vesting of all of the Profits Interest Units.

(d) Distributions. The Company shall make tax and other distributions to the Grantee in accordance with the terms of the Operating Agreement, and all such distributions shall be subject to the terms of the Operating Agreement.

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(e) Termination of Rights as to Forfeited Restricted Units. The Grantee shall have no rights with respect to any Restricted Units that are forfeited to the Company. Such Restricted Units shall be deemed to have been forfeited pursuant to this Section 2, whether or not the certificate(s) (if any) for such Restricted Units have been delivered to the Company and whether or not the Company takes any action.

(f) Additional or Exchanged Securities and Property. In the event that any recapitalization, reorganization, merger, split-up, spin-off, subdivision or combination of Common Units, repurchase, or exchange of Common Units or other securities of the Company, or other change in the capital structure of the Company affecting the Common Units occurs, appropriate adjustments to reflect the exchange or distribution of such securities or property shall be made to the number and/or class of the Restricted Units. Any Restricted Units shall immediately be subject to the same vesting provisions that were applicable to such Restricted Units prior to the adjustment described in this Subsection (f).

(g) Repurchase. The Grantee further agrees to surrender to the Company any Restricted or Vested Units subject to repurchase by the Company as provided in Section 6(c) of the Plan.

SECTION 3. No Registration Rights. The Company may, but shall not be obligated to, register or qualify the sale of Profits Interest Units under the Securities Act or any other applicable law. The Company shall not be obligated to take any affirmative action in order to cause the sale of Profits Interest Units under this Agreement to comply with any law.

SECTION 4. Restrictions On Transfer.

(a) Transfer of Restricted Units. The Grantee shall not sell, pledge, assign, hypothecate, or otherwise transfer any Restricted Units without the Company’s written consent.

(b) Operating Agreement. Vested Units acquired under this Agreement shall be subject to the transfer provisions of the Operating Agreement, including (without limitation) any right of first refusal or buy/sell agreement.

(c) Market Stand-Off.

(i) Neither the Grantee nor any holder the Profits Interest Units acquired under this Agreement (either, a “Holder”) shall sell or otherwise transfer, make any short sale of, grant any option for the purchase of, or enter into any hedging or similar transaction with the same economic effect as a sale, of any Profits Interest Units acquired under this Agreement (or other equity securities of the Successor Entity) held by such Holder (other than those included in the registration) during the one hundred eighty (180) day period following the effective date of the registration statement for the Company’s Initial Public Offering filed under the Securities Act (or such other period as may be requested by the Company or an underwriter to accommodate regulatory restrictions on (i) the publication or other distribution of research reports and (ii) analyst recommendations and opinions, including, but not limited to, the restrictions contained in NASD Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto). The

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obligations described in this Section 4(c) shall not apply to a registration relating solely to employee benefit plans on Form S-l or Form S-8 or similar forms that may be promulgated in the future, or a registration relating solely to a transaction on Form S-4 or similar forms that may be promulgated in the future. The Company may impose stop-transfer instructions and may stamp each such certificate with appropriate legends with respect to the Company Securities (or other securities) subject to the foregoing restriction until the end of such one hundred eighty (180) day (or other) period. Each Holder agrees to execute a market standoff agreement with said underwriters in customary form consistent with the provisions of this Section

(ii) The Grantee agrees to execute and deliver such other agreements as may be reasonably requested by the Company, the Successor Entity or the underwriter which are consistent with Subsection (c)(i) or which are necessary to give further effect thereto. In addition, if requested by the Company, the Successor Entity or the representative of the underwriters of Profits Interest Units (or other securities) of the Company or the Successor Entity, the Grantee shall provide, within ten (10) days of such request, such information as may be required by the Company, the Successor Entity or such representative in connection with the completion of any public offering of the Company’s or the Successor Entity’s securities pursuant to a registration statement filed under the Securities Act. The obligations described in this Subsection (c) shall not apply to a registration relating solely to employee benefit plans on Form S-1 or Form S-8 or similar forms that may be promulgated in the future, or a registration relating solely to a Commission Rule 145 transaction on Form S-4 or similar forms that may be promulgated in the future.

(d) Securities Law Restrictions. Regardless of whether the offering and issuance of Profits Interest Units under this Agreement have been registered under the Securities Act or have been registered or qualified under the securities laws of any state, the Company at its discretion may impose restrictions upon the sale, pledge or other transfer of the Profits Interest Units (including the placement of appropriate legends on Profit Interest Unit certificates or the imposition of stop transfer instructions) if, in the judgment of the Company, such restrictions are necessary or desirable in order to achieve compliance with the Securities Act, the securities laws of any state or any other law.

(e) Grantee Representations. In connection with the issuance and acquisition of the under this Agreement, the Grantee hereby represents and warrants to the Company as follows:

(i) The Grantee is acquiring and will hold the Profits Interest Units for investment for his or her account only and not with a view to, or for resale in connection with, any “distribution” thereof within the meaning of the Securities Act.

(ii) The Grantee understands that the Profits Interest Units have not been registered under the Securities Act by reason of a specific exemption therefrom and that the Profits Interest Units must be held indefinitely, unless they are subsequently registered under the Securities Act or the Grantee obtains an opinion of counsel, in form and substance satisfactory to the Company and its counsel, that such registration is not required. The Grantee further acknowledges and understands that the Company is under no obligation to register the Profits Interest Units.

(iii) The Grantee is aware of the adoption of Rule 144 by the Securities and Exchange Commission under the Securities Act, which permits limited public resales of securities

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acquired in a non-public offering, subject to the satisfaction of certain conditions, including (without limitation) the availability of certain current public information about the issuer, the resale occurring only after the holding period required by Rule 144 has been satisfied, the sale occurring through an unsolicited “broker’s transaction,” and the amount of securities being sold during any three month period not exceeding specified limitations. The Grantee acknowledges and understands that the conditions for resale set forth in Rule 144 have not been satisfied and that the Company has no plans to satisfy these conditions in the foreseeable future.

(iv) The Grantee will not sell, transfer or otherwise dispose of the Profits Interest Units in violation of the Securities Act, the Securities Exchange Act of 1934, or the rules promulgated thereunder, including Rule 144 under the Securities Act. The Grantee agrees that he or she will not dispose of the Profits Interest Units unless and until he or she has complied with all requirements of this Agreement applicable to the disposition of Profits Interest Units and he or she has provided the Company with written assurances, in substance and form satisfactory to the Company, that (A) the proposed disposition does not require registration of the Profits Interest Units under the Securities Act or all appropriate action necessary for compliance with the registration requirements of the Securities Act or with any exemption from registration available under the Securities Act (including Rule 144) has been taken and (B) the proposed disposition will not result in the contravention of any transfer restrictions applicable to the Profits Interest Units under the securities laws or regulations of any State.

(v) The Grantee has been furnished with, and has had access to, such information as he or she considers necessary or appropriate for deciding whether to invest in the Profits Interest Units, and the Grantee has had an opportunity to ask questions and receive answers from the Company regarding the terms and conditions of the issuance of the Profits Interest Units.

(vi) The Grantee is aware that his or her investment in the Company is a speculative investment that has limited liquidity and is subject to the risk of complete loss. The Grantee is able, without impairing his or her financial condition, to hold the Profits Interest Units for an indefinite period and to suffer a complete loss of his or her investment in the Profits Interest Units.

(f) Rights of the Company. The Company shall not be required to (i) transfer on its books any Profits Interest Units that have been sold or transferred in contravention of this Agreement or the Operating Agreement or (ii) treat as a Member of the Company or as the owner of Profits Interest Units, or otherwise to accord voting, distribution or liquidation rights to, any transferee to whom Profits Interest Units have been transferred in contravention of this Agreement or the Operating Agreement.

(g) Administration. Any determination by the Company and its counsel in connection with any of the matters set forth in this Section 4 shall be conclusive and binding on the Grantee and all other persons.

SECTION 5. Adjustment of Profits Interest Units. In the event of any transaction described in Section 11(a) of the Plan, the number and class of Common Units granted as Profits Interest Units shall be adjusted as set forth in Section 11(a) of the Plan and the Profits Interest Distribution

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Threshold shall be appropriately adjusted. In the event of a Liquidity Event (other than a Liquidity Event resulting from the exercise of the Buy-Out Option), this Profits Interest Unit Award shall be subject to the agreement governing the Liquidity Event (subject to Section 11(b) of the Plan) and the Operating Agreement. Upon the consummation of a Liquidity Event resulting from the exercise of the Buy-Out Option, this Profits Interest Unit Award shall be subject to Section 12 of the Plan.

SECTION 6. Successors And Assigns. Except as otherwise expressly provided to the contrary, the provisions of this Agreement shall inure to the benefit of, and be binding upon, the Company and its successors and assigns and be binding upon the Grantee and the Grantee’s legal representatives, heirs, legatees, distributees, assigns and transferees by operation of law, whether or not any such person has become a party to this Agreement or the Operating Agreement or has agreed in writing to join herein and to be bound by the terms, conditions and restrictions hereof or of the Operating Agreement.

SECTION 7. No Retention Rights. Nothing in this Agreement shall confer upon the Grantee any right to continue in Service for any period of specific duration or interfere with or otherwise restrict in any way the rights of the Company (or any Parent or Subsidiary employing or retaining the Grantee) or of the Grantee, which rights are hereby expressly reserved by each, to terminate his or her Service at any time and for any reason, with or without cause.

SECTION 8. Tax Election. The acquisition of the Profits Interest Units may result in adverse tax consequences that may be avoided or mitigated by filing an election under Code Section 83(b). Such election may be filed only within 30 days after the date of purchase. The form for making the Code Section 83(b) election is attached to this Agreement as Exhibit I. The Grantee should consult with his or her tax advisor to determine the tax consequences of acquiring the Profits Interest Units and the advantages and disadvantages of filing the Code Section 83(b) election. The Grantee acknowledges that it is his or her sole responsibility, and not the Company’s, to file a timely election under Code Section 83(b), even if the Grantee requests the Company or its representatives to make this filing on his or her behalf.

SECTION 9. Legends. All certificates evidencing Profits Interest Units shall bear the following legends:

“THE INTERESTS EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR THE SECURITIES LAWS OF ANY STATE. SUCH INTERESTS HAVE BEEN ACQUIRED FOR INVESTMENT, AND MAY NOT BE SOLD, TRANSFERRED, ASSIGNED, PLEDGED, HYPOTHECATED IN THE ABSENCE OF EFFECTIVE REGISTRATION STATEMENTS COVERING SUCH SECURITIES UNDER THE SECURITIES ACT AND ANY APPLICABLE STATE SECURITIES LAWS, UNLESS SUCH REGISTRATION IS NOT REQUIRED PURSUANT TO ONE OR MORE EXEMPTIONS UNDER THE SECURITIES ACT AND/OR STATE LAW.

THE INTERESTS REPRESENTED HEREBY ARE SUBJECT TO CERTAIN TRANSFER RESTRICTIONS AND OTHER OBLIGATIONS CONTAINED IN A

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LIMITED LIABILITY COMPANY AGREEMENT AND A WRITTEN AGREEMENT BETWEEN THE COMPANY AND THE REGISTERED HOLDER OF THE INTERESTS (OR THE PREDECESSOR IN INTEREST TO THE INTERESTS), A COPY OF WHICH IS ON FILE WITH THE COMPANY AND WILL BE FURNISHED WITHOUT COST TO THE HOLDER HEREOF UPON WRITTEN REQUEST TO THE SECRETARY OF THE COMPANY.”

If required by the authorities of any state in connection with the issuance of the Profits Interest Units, the legend or legends required by such state authorities shall also be endorsed on all such certificates.

SECTION 10. Notice. Any notice required by the terms of this Agreement shall be given in writing. It shall be deemed effective upon (i) personal delivery, (ii) deposit with the United States Postal Service, by registered or certified mail, with postage and fees prepaid or (iii) deposit with Federal Express Corporation, with shipping charges prepaid. Notice shall be addressed to the Company at its principal executive office and to the Grantee at the address that he or she most recently provided to the Company in accordance with this Section 10.

SECTION 11. Entire Agreement. The Notice of Profits Interest Unit Grant, this Agreement, the Plan, and the Operating Agreement constitute the entire contract between the parties hereto with regard to the subject matter hereof. They supersede any other agreements, representations or understandings (whether oral or written and whether express or implied) which relate to the subject matter hereof.

SECTION 12. Choice of Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, as such laws are applied to contracts entered into and performed in such State.

SECTION 13. Definitions. Capitalized terms used in this Agreement without definition shall have the meanings given to them in the Operating Agreement. As used in this Agreement:

(a) “Assignee” shall mean a transferee of a Profits Interest Unit who has not been admitted as a Member, as provided in the Operating Agreement.

(b) “Board of Managers” shall have the meaning as provided in the Operating Agreement.

(c) “Date of Grant” shall mean the date specified in the Notice of Profits Interest Unit Grant, which date shall be the later of (i) the date on which the Board of Managers resolved to grant the Profits Interest Units or (ii) the first day of the Grantee’s Service.

(d) “Distribution Threshold” shall mean the minimum amount determined by the Board of Managers in its reasonable discretion to be necessary to cause the Common Unit to constitute a “profits interest” for U.S. federal income tax purposes or such greater amount as the Board of Managers, in its reasonable discretion, may determine.

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(e) “Manager” shall mean a person who serves as a Manager of the Company pursuant to the Operating Agreement.

(f) “Notice of Profits Interest Unit Grant” shall mean the document so entitled to which this Agreement is attached.

(g) “Grantee” shall mean the person named in the Notice of Profits Interest Unit Grant.

(h) “Profits Interest Unit” shall mean a Common Unit issued with a Profits Interest Distribution Threshold Amount.

(i) “Restricted Units” shall mean Profits Interest Units granted under this Agreement that are not Vested Units.

(j) “Service” shall mean service as an Employee, Director, Member or Consultant.

(k) “Successor Entity” means the Company’s successor in a Conversion or otherwise.

(l) “Vest” shall mean the times when Profits Interest Units cease to be subject to forfeiture to the Company in accordance with Section 2 of this Agreement and the Vesting Schedule of the Notice of Profits Interest Unit Grant.

(m) “Vested Units” shall mean Profits Interest Units granted under this Agreement that have vested in accordance with Section 2 of this Agreement and the Vesting Schedule of the Notice of Profits Interest Unit Grant.

IN WITNESS WHEREOF, each of the parties has executed this Agreement, in the case of the Company by its duly authorized officer, as of the day and year first above written.

GRANTEE:	PERSEID THERAPEUTICS LLC
	By:
	Title:

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EXHIBIT I

SECTION 83(b) ELECTION

This statement is made under Section 83(b) of the Internal Revenue Code of 1986, as amended, pursuant to Treasury Regulations Section 1.83-2.

(1) The taxpayer who performed the services is:

Name:                                                                      

Address:                                                                  

Social Security No.:                                               

(2) The property with respect to which the election is made is             Profits Interest Units of Perseid Therapeutics LLC (the “Company”).

(3) The property was transferred on              , 200  .

(4) The taxable year for which the election is made is the calendar year 200  .

The property is subject to forfeiture under the terms of an agreement between the taxpayer and the Company. The forfeiture restrictions lapse upon the satisfaction of certain conditions contained in such agreement.

(5) The fair market value of such property at the time of transfer (determined without regard to any restriction other than a restriction that, by its terms, will never lapse) is $0 per Profits Interest Unit.

(6) The amount paid for such property is $0 per Common Unit.

(7) A copy of this statement was furnished to the person for whom taxpayer rendered the services underlying the transfer of such property.

(8) This statement is executed on              , 200  .

  Signature of Spouse (if any)   Signature of Taxpayer

The deadline for filing this election with the Internal Revenue Service is 30 days after the date of purchase. The election must be filed with the Internal Revenue Service Center where the Grantee files his or her federal income tax returns. The filing should be made by registered or certified mail, return receipt requested. The Grantee must (a) file a copy of the completed form with his or her federal tax return for the current tax year and (b) deliver an additional copy to the Company.

EX-99.1

Exhibit 99.1

For Immediate Release

Maxygen Announces Consummation of Joint Venture

Transaction with Astellas

-Maxygen and Astellas Establish Perseid Therapeutics LLC -

REDWOOD CITY, Calif., September 21, 2009 – Maxygen, Inc. (Nasdaq: MAXY) today announced the consummation of the transactions contemplated by the previously announced joint venture agreement between Maxygen and Astellas Pharma Inc. Under the joint venture transaction, which closed on September 18, 2009, the parties established a newly-formed joint venture, Perseid Therapeutics LLC, to focus on the discovery, research and development of multiple protein pharmaceutical programs.

Under the joint venture arrangement, Maxygen contributed substantially all of its programs and technology assets in protein pharmaceuticals, including its existing MAXY-4 collaboration agreement with Astellas and other early stage programs, together with $10 million in cash, to Perseid in exchange for an ownership interest in Perseid of approximately 83%. Astellas also invested $10 million in Perseid in exchange for the remaining ownership interest of approximately 17%. Astellas has an option to acquire all of Maxygen’s ownership interest in Perseid at specified exercise prices that will increase each three-month period from $53 million to $123 million over the three-years following the closing. Grant Yonehiro, Maxygen’s Chief Business Officer, has been appointed to serve as Chief Executive Officer of Perseid.

As a result of this transaction, substantially all of Maxygen’s research and development operations and personnel have been transferred to Perseid. In addition to its majority ownership of Perseid, Maxygen will continue to retain a number of significant assets, including:

• approximately $185 million in cash;

• its MAXY-G34 program (including the previously announced licensing arrangement with Cangene Corporation for Acute Radiation Syndrome);

• a 22% ownership interest in Codexis, Inc. and a revenue stream from Maxygen’s biofuels license to Codexis;

• a potential $30 million milestone payment from Bayer HealthCare LLC;

• its MolecularBreeding™ platform and intellectual property portfolio (including certain additional fields of application of the technology platform not yet licensed); and

• a fully funded vaccine discovery program.

About Maxygen

Maxygen is a biopharmaceutical company focused on developing improved versions of protein drugs through both internal development and external collaborations and other arrangements. Maxygen uses its proprietary DNA shuffling technology and extensive protein modification expertise to pursue the creation of biosuperior proteins. For more information, please visit our website at www.maxygen.com.

About Astellas

Astellas Pharma Inc., located in Tokyo, Japan, is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceutical products. For more information on Astellas Pharma Inc., please visit its website at http://www.astellas.com/en/.

Cautionary Statement Regarding Maxygen Forward-Looking Statements

This document contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These statements are based on the current expectations and beliefs of Maxygen’s management and are subject to a number of factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. These statements are not guarantees of future performance, involve certain risks, uncertainties and assumptions that are difficult to predict, and are based upon assumptions as to future events that may not prove accurate. Therefore, actual outcomes and results may differ materially from what is expressed herein. For example, there is no assurance that Perseid will be successful or that Astellas will exercise its buy-out option even if Perseid is successful. In any forward-looking statement in which Maxygen expresses an expectation or belief as to future results, such expectation or belief is expressed in good faith and believed to have a reasonable basis, but there can be no assurance that the statement or expectation or belief will result or be achieved or accomplished. The following factors, among others, could cause actual results to differ materially from those described in the forward-looking statements: risks inherent in drug development, such as potential difficulties or delays in the development, testing, regulatory approvals, progression or production of drug compounds, the failure to develop products suitable for commercialization, the delay or suspension of predicted development and commercial timelines for any potential products, the failure to protect intellectual property portfolio and rights; the failure to identify and develop new potential products, and the risk that any compounds developed may have adverse side effects or inadequate therapeutic efficacy, and other economic, business, competitive, and/or regulatory factors affecting Maxygen’s business and the market it serves generally, including those set forth in Maxygen’s most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q, especially in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections, and its Current Reports on Form 8-K and other SEC filings. Maxygen is under no obligation to (and expressly disclaims any such obligation to) update or alter its forward-looking statements whether as a result of new information, future events, or otherwise.

MolecularBreeding™ and Maxygen are U.S. trademarks used by Maxygen, Inc.

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Contact Maxygen:

Dana Fruehling

dana.fruehling@maxygen.com

650.298.5486