-----BEGIN PRIVACY-ENHANCED MESSAGE----- Proc-Type: 2001,MIC-CLEAR Originator-Name: webmaster@www.sec.gov Originator-Key-Asymmetric: MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB MIC-Info: RSA-MD5,RSA, QQ5p0pIZ9eziSv9Enc0BbOMNDM9ROSIa9aTs1Hd7zdJyyTwIDmJ9LaQMbue4f0Bg 0m0q1e4d+l3r6sd+STaIsQ== 0000902595-09-000028.txt : 20090520 0000902595-09-000028.hdr.sgml : 20090520 20090519181907 ACCESSION NUMBER: 0000902595-09-000028 CONFORMED SUBMISSION TYPE: SC 13D PUBLIC DOCUMENT COUNT: 2 FILED AS OF DATE: 20090520 DATE AS OF CHANGE: 20090519 SUBJECT COMPANY: COMPANY DATA: COMPANY CONFORMED NAME: IDM PHARMA, INC. CENTRAL INDEX KEY: 0000822206 STANDARD INDUSTRIAL CLASSIFICATION: PHARMACEUTICAL PREPARATIONS [2834] IRS NUMBER: 330245076 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13D SEC ACT: 1934 Act SEC FILE NUMBER: 005-46179 FILM NUMBER: 09840620 BUSINESS ADDRESS: STREET 1: 9 PARKER, SUITE 100 CITY: IRVINE STATE: CA ZIP: 92618-1605 BUSINESS PHONE: 949-470-4751 MAIL ADDRESS: STREET 1: 9 PARKER, SUITE 100 CITY: IRVINE STATE: CA ZIP: 92618-1605 FORMER COMPANY: FORMER CONFORMED NAME: EPIMMUNE INC DATE OF NAME CHANGE: 19990715 FORMER COMPANY: FORMER CONFORMED NAME: CYTEL CORP/DE DATE OF NAME CHANGE: 19940324 FILED BY: COMPANY DATA: COMPANY CONFORMED NAME: Palo Alto Investors, LLC CENTRAL INDEX KEY: 0001306923 IRS NUMBER: 770558164 STATE OF INCORPORATION: CA FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13D BUSINESS ADDRESS: STREET 1: 470 UNIVERSITY AVE CITY: PALO ALTO STATE: CA ZIP: 94301 BUSINESS PHONE: 650-325-0772 MAIL ADDRESS: STREET 1: 470 UNIVERSITY AVE CITY: PALO ALTO STATE: CA ZIP: 94301 SC 13D 1 sng13d-amend_2.htm SCHEDULE 13D, AMENDMENT NO. 2

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

OMB APPROVAL

OMB Number: 3235-0145

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SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 2)

IDM Pharma, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

449394105

(CUSIP Number)

Warren T. Lazarow, Esq.

Paul S. Scrivano, Esq.

O'Melveny & Myers LLP

O’Melveny & Myers LLP

2765 Sand Hill Road

Times Square Tower

Menlo Park, CA 94025

7 Times Square

(650) 473-2600

New York, New York 10036

(212) 326-2000

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

May 18, 2009

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of sections 240.13d-1(e), 240.13d-1(f) or 140.13d-1(g), check the following box. x

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See section 240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Page 1 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Investors

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 11,322,662

9. Sole Dispositive Power 0

10. Shared Dispositive Power 11,322,662

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

11,322,662

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

43.2%

14.

Type of Reporting Person (See Instructions)

CO, HC

Page 2 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Investors, LLC

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 11,322,662

9. Sole Dispositive Power 0

10. Shared Dispositive Power 11,322,662

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

11,322,662

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

43.2%

14.

Type of Reporting Person (See Instructions)

IA, OO

Page 3 of 21

CUSIP No. 449394105

Names of Reporting Persons

William Leland Edwards

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

_______

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 11,322,662

9. Sole Dispositive Power 0

10. Shared Dispositive Power 11,322,662

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

11,322,662

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

______

13.

Percent of Class Represented by Amount in Row (11)

43.2%

14.

Type of Reporting Person (See Instructions)

IN, HC

Page 4 of 21

CUSIP No. 449394105

Names of Reporting Persons

Anthony Joonkyoo Yun, MD

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

U.S.A.

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 11,322,662

9. Sole Dispositive Power 0

10. Shared Dispositive Power 11,322,662

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

11,322,662

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

43.2%

14.

Type of Reporting Person (See Instructions)

IN, HC

Page 5 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Healthcare Master Fund, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

Cayman Islands

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 3,312,600

9. Sole Dispositive Power 0

10. Shared Dispositive Power 3,312,600

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

3,312,600

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

12.9%

14.

Type of Reporting Person (See Instructions)

Page 6 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Healthcare Fund, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of Shares Beneficially Owned by Each Reporting Person With	7. Sole Voting Power 0
	8. Shared Voting Power 2,656,705
	9. Sole Dispositive Power 0
	10. Shared Dispositive Power 2,656,705

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

2,656,705

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

10.4%

14.

Type of Reporting Person (See Instructions)

Page 7 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Healthcare Master Fund II, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

Cayman Islands

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 2,089,654

9. Sole Dispositive Power 0

10. Shared Dispositive Power 2,089,654

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

2,089,654

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

8.3%

14.

Type of Reporting Person (See Instructions)

Page 8 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Healthcare Fund II, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of Shares Beneficially Owned by Each Reporting Person With	7. Sole Voting Power 0
	8. Shared Voting Power 1,742,771
	9. Sole Dispositive Power 0
	10. Shared Dispositive Power 1,742,771

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

1,742,771

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

6.9%

14.

Type of Reporting Person (See Instructions)

Page 9 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Small Cap Master Fund, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

Cayman Islands

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 2,532,219

9. Sole Dispositive Power 0

10. Shared Dispositive Power 2,532,219

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

2,532,219

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

9.9%

14.

Type of Reporting Person (See Instructions)

Page 10 of 21

CUSIP No. 449394105

Names of Reporting Persons

Palo Alto Small Cap Fund, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 2,133,395

9. Sole Dispositive Power 0

10. Shared Dispositive Power 2,133,395

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

2,133,395

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

8.4%

14.

Type of Reporting Person (See Instructions)

Page 11 of 21

CUSIP No. 449394105

Names of Reporting Persons

Micro Cap Partners, L.P.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

(b)

SEC Use Only

Source of Funds (See Instructions)

Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

Citizenship or Place of Organization

California

Number of

Beneficially

Owned by

Each Reporting

Person With

7. Sole Voting Power 0

8. Shared Voting Power 2,234,025

9. Sole Dispositive Power 0

10. Shared Dispositive Power 2,234,025

11.

Aggregate Amount Beneficially Owned by Each Reporting Person

2,234,025

12.

Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See

Instructions)

13.

Percent of Class Represented by Amount in Row (11)

8.7%

14.

Type of Reporting Person (See Instructions)

Page 12 of 21

CUSIP No. 449394105

Item 1.

Security and Issuer

This statement relates to shares of Common Stock (the "Stock") of IDM Pharma, Inc. (the "Issuer"). The principal executive office of the Issuer is located at 9 Parker, Suite 100, Irvine, CA 92618.

Item 2. Identity and Background

The persons filing this statement and the persons enumerated in Instruction C of Schedule 13D and, where applicable, their respective places of organization, general partners, directors, executive officers and controlling persons, and the information regarding them, are as follows:

(a)

William Leland Edwards, Palo Alto Investors, LLC ("PAI LLC"), Palo Alto Investors ("PAI Corp"), Anthony Joonkyoo Yun, MD, Palo Alto Healthcare Master Fund, L.P. ("Healthcare Master"), Palo Alto Healthcare Fund, L.P. ("Healthcare"), Palo Alto Healthcare Master Fund II, L.P. (“Healthcare Master II”), Palo Alto Healthcare Fund II, L.P. (“Healthcare II”), Palo Alto Small Cap Master Fund, L.P. ("Small Cap Master"), Palo Alto Small Cap Fund, L.P. ("Small Cap") and Micro Cap Partners, L.P. ("Micro Cap") (collectively, the "Filers").

(b)

The business address of Mr. Edwards, PAI LLC, PAI Corp, Mr. Yun, Healthcare, Healthcare II, Small Cap, and Micro Cap is:

470 University Avenue, Palo Alto, CA 94301

The business address of Healthcare Master, Healthcare Master II and Small Cap Master is:

Citco Fund Services (Bermuda) Limited, Washington Mall West, 2nd Floor, 7 Reid Street, Hamilton HM 11, Bermuda

(c)

Present principal occupation or employment or the Filers and the name, principal business and address of any corporation or other organization in which such employment is conducted:

PAI LLC is an investment adviser registered with the Securities and Exchange Commission and is the general partner of, and investment adviser to, investment limited partnerships, including Healthcare Master, Healthcare, Healthcare Master II, Healthcare II, Small Cap Master, Small Cap and Micro Cap and the investment adviser to investment funds. The sole manager of PAI LLC is PAI Corp. Mr. Edwards is the president and controlling shareholder of PAI Corp and the controlling owner of PAI LLC. Mr. Yun is the president of PAI LLC. Healthcare invests in securities indirectly as a limited partner of Healthcare Master, Healthcare II invests in securities indirectly as a limited partner of Healthcare Master II and Small Cap invests in securities indirectly as a limited partner of Small Cap Master.

(d)

During the last five years, none of the Filers has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e)

During the last five years, none of the Filers was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Page 13 of 21

CUSIP No. 449394105

(f)

Mr. Edwards and Mr. Yun are United States citizens.

Item 3.

Source and Amount of Funds or Other Consideration

The source and amount of funds used in purchasing the Stock were as follows:

Purchaser	Source of Funds	Amount
PAI LLC	Funds Under Management	$35,588,048

Item 4.

Purpose of Transaction

In pursuing their investment purposes, the Filers may from time to time further purchase, hold, vote, trade, dispose of, engage in option, swap or other derivative securities transactions with respect to or otherwise deal in the Stock at times, and in such manner, as they deem advisable to benefit from changes in the Stock's market price, changes in the Issuer's operations, business strategy or prospects, or from the sale or merger of the Issuer. To evaluate such alternatives, the Filers routinely will monitor the Issuer's operations, prospects, business development, management, competitive and strategic matters, capital structure and prevailing market conditions, as well as alternative investment opportunities, the Filers' liquidity requirements and other investment considerations. Consistent with their investment research methods and evaluation criteria, the Filers may discuss such matters with the Issuer's management, other shareholders, industry analysts, existing or potential strategic partners or competitors, investment and financing professionals, sources of credit and other investors. Such factors and discussions may affect materially, and result in, the Filers' modifying their ownership of the Stock, exchanging information with the Issuer pursuant to appropriate confidentiality or similar agreements, proposing changes in the Issuer's operations, governance or capitalization, or in proposing or taking one or more of the actions described in paragraphs (a) through (j) of Item 4 of Schedule 13D with respect to the investment in the Issuer. The Filers may reconsider and change their plans or proposals relating to the Stock at any time.

On May 18, 2009, the Issuer entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Takeda America Holdings, Inc., a New York corporation (“Parent”), and Jade Subsidiary Corporation, a Delaware corporation (“Purchaser”), which provides, among other things, that Purchaser will commence a tender offer to purchase all of the outstanding shares of the Stock for US$2.64 in cash per share (the “Offer”), followed by a merger in which Purchaser will merge with and into the Issuer (the “Merger”) and the remaining shares of the Stock not tendered into the Offer would be converted into the right to receive US$2.64 in cash per share, the same price paid in the Offer. The transaction is subject to the tender of a majority of the Stock on a fully diluted basis as well as other customary closing conditions.

In connection with the Merger Agreement, Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers executed and delivered a Stockholders’ Agreement (the “Stockholders’ Agreement”) with Parent and certain other parties thereto. See Item 6 for a description of the Stockholders’ Agreement.

Item 5.

Interest in Securities of the Issuer

(a), (b), (d) Each Filer's beneficial ownership of the Stock on the date of this report is reflected on that Filer's cover page. PAI LLC is an investment adviser with the power to invest in, vote and dispose of the Stock on behalf of its clients. Its clients have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Stock. No client, other than Healthcare Master, Healthcare, Healthcare Master II, Healthcare II, Small Cap Master, Small Cap, and Micro Cap, individually holds more than 5% of the outstanding Stock. Mr. Edwards is the president and controlling shareholder of PAI Corp., which is the sole manager of PAI LLC, and is the controlling owner of PAI LLC. Mr. Yun is the president of PAI LLC. The Filers are filing this Schedule 13D jointly, but not as members of a group, and each of them expressly disclaims membership in a group. Each of PAI, PAI LLC, Mr. Edwards and Mr. Yun disclaims beneficial ownership of the Stock except to the extent of that

Page 14 of 21

CUSIP No. 449394105

Filer's pecuniary interest therein. In addition, the filing of this Schedule 13D on behalf of Healthcare Master, Healthcare Master II, Healthcare, Healthcare II, Small Cap Master, Small Cap and Micro Cap should not be construed as an admission any of them is, and each of them disclaims that it is, the beneficial owner, as defined in Rule 13d-3 under the Securities Exchange Act of 1934, of any of the Stock covered by this Schedule 13D.

(c) Listed below are the purchases of the Stock by the Filers in open market transactions since the most recent date that this Schedule 13D was filed. There were no other transactions in the Stock by the Filers during such period.

Number of Shares

Filer

Date

Transaction

Purchased or Sold

Average Price Per Share

Healthcare Master II	3/23/2009	Purchase	45,900	$2.37
Healthcare Master II	3/24/2009	Purchase	96,200	$2.38
Healthcare Master II	3/25/2009	Purchase	30,000	$2.47
Healthcare Master II	3/26/2009	Purchase	69,500	$2.53
Healthcare Master II	3/27/2009	Purchase	100,000	$2.53
Healthcare Master II	3/30/2009	Purchase	20,000	$2.05
Healthcare Master	4/1/2009	Sell	243,360	$1.76
Healthcare Master	4/1/2009	Sell	296,640	$1.76
Healthcare Master II	4/1/2009	Purchase	540,000	$1.76

Item 6. Contracts, Arrangement, Understandings or Relationships with Respect to Securities of the Issuer

PAI LLC is the general partner of investment partnerships, including Healthcare Master, Healthcare, Healthcare Master II, Healthcare II, Small Cap Master, Small Cap and Micro Cap, pursuant to agreements of limited partnership that grant to PAI LLC the authority, among other things, to invest the funds of such investment partnerships in the Stock, to vote and dispose of the Stock and to file this statement on behalf of such investment partnerships. Pursuant to such agreements, PAI LLC is entitled to allocations based on assets under management and realized and unrealized gains.

In addition, 964,805 shares of the Stock are represented by warrants (the “Warrants”) subject to the terms of and governed by the agreement incorporated by reference in this Schedule 13D as Exhibit B.

The information set forth in Item 4 is hereby incorporated by reference into this Item 6. Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers entered into the Stockholders’ Agreement, pursuant to which:

Page 15 of 21

CUSIP No. 449394105

•

During the Support Period (as defined below), Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers agreed that no later than the expiration date of the Offer, such stockholders shall tender 10,357,857 shares of Stock and any shares issued upon the exercise of the Warrants (the “Owned Shares”) into the Offer pursuant to the terms and conditions of the Offer. Such stockholders also agreed not to withdraw any of such stockholder’s Owned Shares during the Support Period after such Owned Shares have been tendered in the Offer. With respect to Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and the affiliates of the Filers party to the Stockholders’ Agreement, the term “Support Period” means the period commencing on May 18, 2009 and continuing until the first to occur of (a) the acceptance for payment of any shares of the Stock pursuant to the Offer, (b) July 22, 2009, (c) a Company Adverse Recommendation Change (as defined in the Merger Agreement), (d) the receipt by the Issuer or the Issuer’s board of directors, or the public announcement of, a Superior Offer (as defined in the Stockholders’ Agreement) or (e) the termination of the Stockholders’ Agreement pursuant to section 6.1 thereof.

•

During the Support Period, Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers agreed, except as provided in the Stockholders’ Agreement, not to sell, transfer, pledge, encumber, assign or otherwise dispose of, or enter into any agreement or option with respect to the sale, transfer, pledge, encumbrance, assignment or other disposition of, or limitation on the voting rights of, any of the Owned Shares; provided, that (i) nothing in the Stockholders’ Agreement prohibits such stockholders from tendering any Owned Shares into the Offer or from exercising any options or warrants and (ii) such stockholders are permitted to distribute Owned Shares to their respective general partner, limited partners or affiliates if certain conditions, as set forth in the Stockholders’ Agreement, are met.

•

Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers agreed to certain non-solicitation provisions with respect to Acquisition Proposals, subject to certain exceptions upon the termination of the Support Period, as set forth in section 4.4 of the Stockholders’ Agreement.

•

Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers agreed not to exercise any rights (including under section 262 of the Delaware General Corporation Law) to demand appraisal of any Owned Shares that may arise with respect to the Merger.

•

Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers authorized the Issuer or the Issuer’s counsel during the Support Period to notify the Issuer’s transfer agent that there is a stop transfer order with respect to all of the Owned Shares. Such stop transfer order shall be removed and shall be of no further force and effect upon the termination of the Support Period.

•

Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain affiliates of the Filers made certain representations and warranties to Parent in the Stockholders’ Agreement with respect to, among other things, its ownership of the Owned Shares free and clear of encumbrances and its authority to enter into the Stockholders’ Agreement.

•

The Stockholders’ Agreement will terminate upon the earlier of (i) the termination of the Merger Agreement in accordance with its terms, (ii) the occurrence of a Non-Permissible Amendment (as defined below), and (iii) the acceptance for payment of any shares of the Stock pursuant to the Offer. The term “Non-Permissible Amendment” means any amendment, waiver or modification to the Merger Agreement made without the prior written consent of the stockholders party to the Stockholders’ Agreement that (a) changes the form of the consideration with respect to the Offer, (b) decreases the amount of the consideration with respect to the Offer, (c) extends the Outside Date (as defined in the Merger Agreement), (d) adds additional conditions to the Offer or (e) otherwise materially and adversely affects the stockholders party to the Stockholders’ Agreement.

References to, and descriptions of, the Stockholders’ Agreement are qualified in their entirety by reference to the copy thereof included as an exhibit to this Schedule 13D and incorporated herein.

Page 16 of 21

CUSIP No. 449394105

Item 7. Material to Be Filed as Exhibits

Exhibit A

Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G.

Exhibit B

Warrant Agreement, incorporated by reference to form of warrant to purchase common stock attached as an exhibit to the Issuer's Form 8-K filed on February 21, 2007 and the common stock purchase warrant filed as an exhibit to the Issuer's Form 8-K filed on June 21, 2007.

Exhibit C

Stockholders’ Agreement, dated as of May 18, 2009, among Parent, Healthcare Master, Healthcare Master II, Small Cap Master, Micro Cap and certain other parties thereto.

Page 17 of 21

CUSIP No. 449394105

SIGNATURES

After reasonable inquiry and to the best of my knowledge, I certify that the information set forth in this statement is true, complete and correct.

Dated:

May 19, 2009

PALO ALTO INVESTORS

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO INVESTORS, LLC

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE MASTER FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE MASTER FUND II, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO SMALL CAP MASTER FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE FUND II, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO SMALL CAP FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

MICRO CAP PARTNERS, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

Page 18 of 21

CUSIP No. 449394105

/s/ Anthony Joonkyoo Yun

Anthony Joonkyoo Yun, MD

/s/ William Leland Edwards

William L. Edwards

Page 19 of 21

CUSIP No. 449394105

EXHIBIT A

AGREEMENT REGARDING JOINT FILING

OF STATEMENT ON SCHEDULE 13D OR 13G

The undersigned agree to file jointly with the Securities and Exchange Commission (the "SEC") any and all statements on Schedule 13D or Schedule 13G (and any amendments or supplements thereto) required under section 13(d) of the Securities Exchange Act of 1934, as amended, in connection with purchases and sales by the undersigned of the securities of any issuer until such time as the undersigned file with the SEC a statement terminating this Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G. For that purpose, the undersigned hereby constitute and appoint Palo Alto Investors, LLC, a California limited liability company, as their true and lawful agent and attorney-in-fact, with full power and authority for and on behalf of the undersigned to prepare or cause to be prepared, sign, file with the SEC and furnish to any other person all certificates, instruments, agreements and documents necessary to comply with section 13(d) and section 16(a) of the Securities Exchange Act of 1934, as amended, in connection with said purchases and sales, and to do and perform every act necessary and proper to be done incident to the exercise of the foregoing power, as fully as the undersigned might or could do if personally present, until such time as the undersigned file with the SEC a statement terminating this Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G.

Dated:

May 19, 2009

PALO ALTO INVESTORS

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO INVESTORS, LLC

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE MASTER FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

Page 20 of 21

CUSIP No. 449394105

PALO ALTO HEALTHCARE MASTER FUND II, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO SMALL CAP MASTER FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO HEALTHCARE FUND II, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

PALO ALTO SMALL CAP FUND, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

MICRO CAP PARTNERS, L.P.

By: Palo Alto Investors, LLC, General Partner

By: Palo Alto Investors, Manager

By: /s/ Mark Shamia
Mark Shamia, Chief Operating Officer

/s/ Anthony Joonkyoo Yun

Anthony Joonkyoo Yun, MD

/s/ William Leland Edwards

William L. Edwards

Page 21 of 21

EX-99 2 stockholders_agreement.htm EXHIBIT C STOCKHOLDERS AGREEMENT

Exhibit C

STOCKHOLDERS’ AGREEMENT

This STOCKHOLDERS’ AGREEMENT (this “Agreement”), is dated as of May 18, 2009, among Takeda America Holdings, Inc., a New York corporation (the “Parent”) and the stockholders listed on the signature pages hereto (each a “Stockholder” and collectively, the “Stockholders”).

WHEREAS, Parent, Jade Subsidiary Corporation, a Delaware corporation and a wholly owned Subsidiary of the Parent (the “Purchaser”), and IDM Pharma, Inc., a Delaware corporation (the “Company”), are entering into an Agreement and Plan of Merger, dated as of the date hereof (as it may be amended from time to time in accordance with its terms, the “Merger Agreement”), providing for, among other things, Purchaser to commence a cash tender offer (the “Offer”) to acquire all of the outstanding shares of common stock, $0.01 par value per share, of the Company (the “Company Common Stock”) followed by the subsequent merger of Purchaser with and into the Company with the Company surviving the merger as a wholly owned Subsidiary of the Parent, in each case, on the terms and subject to the conditions set forth in therein (capitalized terms used herein and not otherwise defined shall have the meanings ascribed to such terms in the Merger Agreement); and

WHEREAS, as of the date hereof, each Stockholder is the beneficial owner of the number of shares of Company Common Stock set forth, and in the manner reflected, on Attachment A hereto (the “Owned Shares”); and

WHEREAS, as a condition to Parent and Purchaser’s willingness to enter into and perform its obligations under the Merger Agreement, Parent and Purchaser have required that each Stockholder agree, and each Stockholder has agreed, (i) on the terms and conditions described herein, to tender in the Offer (and not withdraw) all of such Stockholders’ Owned Shares as well as any shares of Company Common Stock acquired by such Stockholder after the execution of this Agreement (all of which, after so acquired, shall constitute “Owned Shares”), whether upon the exercise of options, warrants, conversion of convertible securities or otherwise, and (ii) to take the other actions described herein; and

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration given to each party hereto, the receipt of which is hereby acknowledged, the parties agree as follows:

Agreement to Tender.

1.1 Agreement to Tender. During the Support Period (as defined below), each Stockholder hereby agrees that, no later than the expiration date of the Offer, such Stockholder shall (i) deliver to the depositary designated in the Offer (A) a letter of transmittal with respect to such Stockholder’s Owned Shares complying with the terms of the Offer, (B) certificates representing such Stockholder’s Owned Shares or an “agent’s message” in the case of a book-entry transfer of any uncertificated Owned Shares and (C) all other documents or instruments required to be delivered pursuant to the terms of the Offer, and/or (ii) instruct such Stockholder’s broker or such other person who is the holder of record of any of such Stockholder’s Owned Shares to so tender such Owned Shares in the Offer pursuant to the terms and conditions of the

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Offer. During the Support Period, each Stockholder hereby agrees not to withdraw any of such Stockholder’s Owned Shares after such Owned Shares have been tendered in the Offer. The term “Support Period” means (x) in the case of any Stockholder who is a director or officer of the Company as of the date hereof, the period commencing on the date hereof and continuing until the termination of this Agreement pursuant to Section 6.1, (y) in the case of the Stockholders identified on Attachment A with an “*”,the period commencing on the date hereof and continuing until the first to occur of (a) the Specified Time, (b) the Outside Date, (c) a Company Adverse Recommendation Change, (d) the receipt by the Company or the Company Board, or the public announcement of, a Superior Offer (as defined below) or (e) the termination of this Agreement pursuant to Section 6.1 and (z) in the case of any other Stockholder not described in clauses (x) and (y), the period commencing on the date hereof and continuing until the first to occur of (a) the Specified Time, (b) the Outside Date, (c) a Company Adverse Recommendation Change or (d) the termination of this Agreement pursuant to Section 6.1. The term “Superior Offer” means any unsolicited, bona fide written proposal made by a third party to acquire all or substantially all the equity securities or all or substantially all of the assets of the Company, pursuant to a tender or exchange offer, a merger, consolidation or a sale of its assets, (i) at a per share price that is higher than the per share price of the Offer Consideration and (ii) that is reasonably capable of being completed on the terms proposed, taking into account all financial, regulatory, legal and other aspects of such proposal; provided, however, that no Acquisition Proposal shall be deemed to be a Superior Offer if any financing required to consummate the transaction is not committed.

2. Representations and Warranties of Stockholders. Each Stockholder hereby represents and warrants, severally and not jointly, to Parent as follows:

2.1 Due Organization. Such Stockholder, if a corporation or other entity, has been duly organized, is validly existing and is in good standing under the laws of the state of its formation or organization, except where the failure to be so organized, in valid existence or in good standing, individually or in the aggregate, would not be reasonably expected to have a material adverse effect on such Stockholder’s ability to perform its obligations under this Agreement in a timely manner.

2.2 Power; Due Authorization; Binding Agreement. Such Stockholder has full legal capacity, power and authority to execute and deliver this Agreement, to perform its obligations hereunder and to consummate the transactions contemplated hereby. This Agreement has been duly and validly executed and delivered by such Stockholder and constitutes a valid and binding agreement of such Stockholder, enforceable against such Stockholder in accordance with its terms, except to the extent that such enforceability (i) may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to creditors’ rights generally, and (ii) is subject to general principles of equity.

2.3 Ownership of Shares. On the date hereof, the Owned Shares set forth opposite such Stockholder’s name on Attachment A hereto are owned of record or beneficially by such Stockholder in the manner reflected thereon, free and clear of any claims, liens, encumbrances and security interests except for those arising under the federal securities laws and as contemplated by this Agreement. On the date hereof, such Stockholder does not own of record or beneficially any voting securities of the Company (“Voting Shares”) other than the

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Owned Shares. As of the date hereof such Stockholder has, and as of the expiration of the Offer, such Stockholder will have, sole voting power and sole dispositive power with respect to all of the Owned Shares owned by such Stockholder; provided that in the case of the Stockholders identified on Attachment A with an “*”, such Stockholders may transfer among themselves voting power and dispositive power with respect to the Owned Shares owned by any of them.

2.4 No Conflicts. The execution and delivery of this Agreement by such Stockholder does not, and the performance of the terms of this Agreement by such Stockholder will not, and the consummation by such Stockholder of the transactions contemplated hereby will not, (a) require such Stockholder to obtain the consent or approval of, or make any filing with or notification to, any governmental or regulatory authority, domestic or foreign, (b) require the consent or approval of any other person pursuant to any agreement, obligation or instrument binding on such Stockholder or its properties and assets, (c) conflict with or violate any organizational document or law, rule, regulation, order, judgment or decree applicable to such Stockholder or pursuant to which any of its or its affiliates’ respective properties or assets are bound or (d) violate any other agreement to which such Stockholder or any of its affiliates is a party including any voting agreement, stockholders agreement, irrevocable proxy or voting trust, except for, in the case of each of clauses (a) through (d), (i) filings, authorizations, notifications, consents or approvals as may be required under the Exchange Act, and (ii) where the occurrence of any of the foregoing, individually or in the aggregate, would not reasonably be expected to have a material adverse effect on such Stockholder’s ability to perform its obligations under this Agreement in a timely manner. Such Stockholder’s Voting Shares are not, with respect to the voting or transfer thereof, subject to any other agreement, including any voting agreement, stockholders agreement, irrevocable proxy or voting trust.

2.5 Acknowledgment. Such Stockholder understands and acknowledges that each of Parent and Purchaser is entering into the Merger Agreement in reliance upon such Stockholder’s execution, delivery and performance of this Agreement.

3. Representations and Warranties of Parent. Parent hereby represents and warrants to the Stockholders as follows:

3.1 Power; Due Authorization; Binding Agreement. Parent is a corporation duly organized, validly existing and in good standing under the laws of its jurisdiction of incorporation. Parent has full corporate power and authority to execute and deliver this Agreement, to perform its obligations hereunder and to consummate the transactions contemplated hereby. The execution and delivery of this Agreement and the consummation by Parent of the transactions contemplated hereby have been duly and validly authorized by all necessary corporate action on the part of Parent, and no other proceedings on the part of Parent are necessary to authorize this Agreement or to consummate the transactions contemplated hereby. This Agreement has been duly and validly executed and delivered by Parent and constitutes a valid and binding agreement of Parent, except to the extent that such enforceability (i) may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to creditors’ rights generally, and (ii) is subject to general principles of equity.

3.2 No Conflicts. The execution and delivery of this Agreement by Parent does not, the performance of the terms of this Agreement by Parent will not, and the

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consummation by Parent of the transactions contemplated hereby will not, (a) require Parent to obtain the consent or approval of, or make any filing with or notification to, any governmental or regulatory authority, domestic or foreign or (b) conflict with or violate any organizational document or law, rule, regulation, order, judgment or decree applicable to Parent or pursuant to which any of its or its Subsidiaries’ respective assets are bound.

3.3 Acknowledgement; Funds. Parent understands and acknowledges that the Stockholders are entering into this Agreement in reliance upon Parent’s execution, delivery and performance of the Merger Agreement. Parent has available cash resources in an amount sufficient to consummate the Offer and the Merger.

4. Certain Covenants of the Stockholders. Each Stockholder hereby covenants and agrees, severally and not jointly, with Parent as follows:

4.1 Restriction on Transfer, Proxies and Non-Interference. Each Stockholder hereby agrees, during the Support Period, at any time prior to the Specified Time, not to (a) other than as may be required by law or court order, sell, transfer, pledge, encumber (other than the encumbrances set forth in this Agreement), assign or otherwise dispose of, or enter into any agreement (other than this Agreement) or option with respect to the sale, transfer, pledge, encumbrance, assignment or other disposition of, or limitation on the voting rights of, any of the Owned Shares (any such action, a “Transfer”), provided that nothing in this Agreement shall prohibit such Stockholder from tendering any Owned Shares in the Offer, voting in favor of adoption of the Merger Agreement, or from exercising any options or warrants to purchase Owned Shares; and provided, further, that each Stockholder who is not a director or executive officer of the Company as of the date hereof shall be permitted to distribute Owned Shares to its general partners, limited partners or Affiliates if and only if such Stockholder and its general partners, limited partners or Affiliates enter into an agreement with Parent in a form reasonably acceptable to Parent providing (x) a power of attorney allowing such Stockholder to tender such Owned Shares as provided in Section 1.1, (y) requiring the Stockholder to exercise such power of attorney and tender such Owned Shares as provided in Section 1.1, and (z) that such general partners, limited partners or Affiliates will comply with the other restrictions in this Agreement as such restrictions bind such Stockholder, (b) grant any proxies or powers of attorney, deposit any Owned Shares into a voting trust or enter into a voting agreement (other than this Agreement) with respect to any Owned Shares, or (c) commit or agree to take any of the foregoing actions. Any action taken in violation of the foregoing sentence shall be null and void ab initio and each Stockholder agrees that any such prohibited action may and should be enjoined. If any involuntary Transfer of any of the Owned Shares shall occur (including a sale by a Stockholder’s trustee in any bankruptcy, or a sale to a purchaser at any creditor’s or court sale), the transferee (which term, as used herein, shall include any transferees and subsequent transferees of the initial transferee) shall take and hold such Owned Shares subject to all of the restrictions, liabilities and rights under this Agreement, which shall continue in full force and effect until valid termination of this Agreement. During the Support Period, each Stockholder shall use commercially reasonable efforts to cause any Owned Shares that are Transferred in any manner by such Stockholder, other than Owned Shares tendered in and accepted for payment in the Offer, to be subject to this Agreement

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4.2 Additional Shares. During the Support Period, each Stockholder hereby agrees that any new Owned Shares acquired by such Stockholder, if any, after the date hereof shall be subject to the terms of this Agreement as though owned by such Stockholder on the date hereof.

4.3 No Limitations on Actions. Each Stockholder signs this Agreement solely in its capacity as the record and/or beneficial owner, as applicable, of the Owned Shares. Any trustee who signs this Agreement on behalf of a Stockholder that is a trust is signing only in his fiduciary capacity and not as an individual. This Agreement shall not limit or otherwise affect the actions of any Stockholder or any affiliate, employee or designee of such Stockholder or any of its affiliates in any other capacity, including such person’s capacity, if any, as an officer of the Company or a member of the board of directors of the Company. Nothing herein shall limit or affect the Company’s rights in connection with the Merger Agreement.

4.4 No Solicitation. Until the termination of this Agreement pursuant to Section 6.1, each Stockholder agrees that it will not, nor will it permit any of its Representatives to, directly or indirectly, (i) solicit, initiate, knowingly encourage or knowingly facilitate any inquiries or the making of any proposal or offer that constitutes, or may reasonably be expected to lead to, any Acquisition Proposal or (ii) during the Support Period, enter into, continue or otherwise participate in any discussions or negotiations regarding, furnish to any person any information with respect to, knowingly assist, or participate in any effort or attempt by any person with respect to, or otherwise knowingly cooperate in any way with, any Acquisition Proposal. Except as may be permitted following the end of the Support Period pursuant to clause (ii) of the immediately preceding sentence, each Stockholder shall, and shall cause its Representatives to, cease immediately all discussions and negotiations regarding any proposal that constitutes, or may reasonably be expected to lead to, an Acquisition Proposal. Notwithstanding anything to the contrary contained herein, (x) if the Company Board has entered into discussions or negotiations with, or provided non-public information to, any person in response to an Acquisition Proposal by such person in compliance with the provisions of the Merger Agreement, each Stockholder who is not a director or officer of the Company as of the date hereof may provide information and engage in discussions or negotiations with such person as and to the extent that the Company is permitted to do so pursuant to the terms of the Merger Agreement and (y) if the Company terminates the Merger Agreement pursuant to Section 9.1(d)(ii) thereof in order to enter into a definitive agreement providing for the implementation of a Superior Proposal, each Stockholder who is not a director or officer of the Company as of the date hereof shall be entitled to enter into a voting or other support agreement with the Person making the Superior Proposal.

4.5 Agreement Not to Exercise Appraisal Rights. Each Stockholder agrees not to exercise any rights (including under Section 262 of the Delaware General Corporation Law) to demand appraisal of any Owned Shares that may arise with respect to the Merger.

4.6 Further Assurances. From time to time, at the reasonable request of Parent and without further consideration, each Stockholder shall execute and deliver, and at the reasonable request of a Stockholder and without further consideration, Parent shall execute and deliver, such additional documents and take all such further action as may be necessary or desirable to consummate and make effective the transactions contemplated by this Agreement.

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5. Stop Transfer Order. In furtherance of this Agreement, and concurrently herewith, each Stockholder shall and hereby does authorize the Company or the Company’s counsel during the Support Period to notify the Company’s transfer agent that there is a stop transfer order with respect to all of the Owned Shares and other Voting Shares. The parties agree that such stop transfer order shall be removed and shall be of no further force and effect upon the termination of the Support Period.

Miscellaneous.

6.1 Termination of this Agreement. This Agreement shall terminate upon the earlier to occur of (i) the termination of the Merger Agreement in accordance with its terms, (ii) the occurrence of a Non-Permissible Amendment (as defined below), and (iii) the Specified Time. The term “Non-Permissible Amendment” means any amendment, waiver or modification to the Merger Agreement made without the prior written consent of the Stockholders that (i) changes the form of the Offer Consideration, (ii) decreases the amount of the Offer Consideration, (iii) extends the Outside Date, (iv) adds additional conditions to the Offer or (v) otherwise materially and adversely affects the Stockholders.

6.2 Effect of Termination. In the event of termination of this Agreement pursuant to Section 6.1, all obligations and agreements of the parties set forth in this Agreement shall forthwith terminate and be of no further force or effect; provided, however, no such termination shall relieve any party hereto from any liability for any breach of this Agreement occurring prior to such termination.

6.3 Non-Survival. The respective representations and warranties of Parent and each Stockholder contained in this Agreement shall expire with, and be terminated and extinguished upon, the Specified Time.

6.4 Expenses. All fees, costs and expenses incurred in connection with this Agreement and the transactions contemplated hereby shall be paid by the party incurring such fees, costs and expenses.

6.5 Entire Agreement; Assignment. This Agreement (including Attachment A hereto) constitutes the entire agreement among the parties hereto and supersedes any prior understandings, agreements or representations by or among the parties hereto, or any of them, written or oral, with respect to the subject matter hereof. Nothing in this Agreement, express or implied, is intended to or shall confer upon any other person any right, benefit or remedy of any nature whatsoever under or by reason of this Agreement. Neither this Agreement nor any of the rights, interests or obligations under this Agreement may be assigned or delegated, in whole or in part, by operation of law or otherwise by any of the parties hereto without the prior written consent of the other parties, and any such assignment without such prior written consent shall be null and void.

6.6 Amendments. This Agreement may not be modified, amended, altered or supplemented, except upon the execution and delivery of a written agreement executed by each of the parties hereto.

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6.7 Notices. All notices and other communications hereunder shall be in writing and shall be deemed duly delivered (i) four business days after being sent by registered or certified mail, return receipt requested, postage prepaid, or (ii) one business day after being sent for next business day delivery, fees prepaid, via a reputable nationwide overnight courier service, in each case to the intended recipient as set forth below:

If to the Stockholders:

c/o IDM Pharma, Inc.

9 Parker, Suite 100

Irvine, CA 92618

Attention:

Timothy P. Walbert

President and Chief Executive Officer

Telecopy No.: (949) 470-6470

with a copy, in the case of the Stockholders identified on Attachment A with an “*”, to:

O’Melveny & Myers LLP

Times Square Tower

7 Times Square

New York, NY 10036

Attention: Paul S. Scrivano

Facsimile No.: (212) 326-2061

and with a copy, in the case of any Stockholder who is an officer or director of the Company as of the date hereof, to:

Cooley Godward Kronish LLP

4401 Eastgate Mall

San Diego, CA 92121

Attention: Barbara L. Borden, Esq.

Facsimile No.: (858) 550-6420

and with a copy, in the case of Medarex, Inc., to:

Corporate Office

707 State Road

Princeton, NJ 08540-1437

Attention: Scott Coiante

Facsimile No.: (609) 430-2851

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If to the Parent:

40 Landsdowne Street

Cambridge, MA 02139

Attention: Laurie B. Keating

Senior Vice President and General Counsel

Telecopy No.: (617) 374-7788

with a copy to:

Wilmer Cutler Pickering Hale and Dorr LLP

60 State Street

Boston, MA 02109

Attention: David E. Redlick

Graham Robinson

Facsimile No.: (617) 526-5000

Any party to this Agreement may give any notice or other communication hereunder using any other means (including personal delivery, messenger service, telecopy, ordinary mail or electronic mail), but no such notice or other communication shall be deemed to have been duly given unless and until it actually is received by the party for whom it is intended. Any party to this Agreement may change the address to which notices and other communications hereunder are to be delivered by giving the other parties to this Agreement notice in the manner herein set forth.

6.8

Governing Law; Venue.

(a) This Agreement shall be governed by and construed in accordance with the internal laws of the State of Delaware without giving effect to any choice or conflict of law provision or rule (whether of the State of Delaware or any other jurisdiction) that would cause the application of laws of any jurisdictions other than those of the State of Delaware.

(b) Each of the parties hereto (i) consents to submit itself to the exclusive personal jurisdiction of the Delaware Court of Chancery, New Castle County, or if that court does not have jurisdiction, a federal court sitting in the State of Delaware in any action or proceeding arising out of or relating to this Agreement or any of the transactions contemplated by this Agreement, (ii) agrees that all claims in respect of such action or proceeding may be heard and determined in any such court, (iii) agrees that it will not attempt to deny or defeat such personal jurisdiction by motion or other request for leave from any such court, and (iv) agrees not to bring any action or proceeding arising out of or relating to this Agreement or any of the transaction contemplated by this Agreement in any other court. Each of the parties hereto waives any defense or inconvenient forum to the maintenance of any action or proceeding so brought and waives any bond, surety or other security that might be required of any other party with respect thereto. To the extent permitted by applicable law, any party hereto may make service on

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another party by sending or delivering a copy of the process to the party to be served at the address and in the manner provided for the giving of notices in Section 6.7. Nothing in this Section 6.8(b), however, shall affect the right of any party to serve legal process in any other manner permitted by law.

6.9 WAIVER OF JURY TRIAL. EACH OF THE PARENT AND THE STOCKHOLDERS HEREBY IRREVOCABLY WAIVES ALL RIGHTS TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM (WHETHER BASED ON CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THE ACTIONS OF THE PARENT OR ANY STOCKHOLDER IN THE NEGOTIATION, ADMINISTRATION, PERFORMANCE AND ENFORCEMENT HEREOF.

6.10 Specific Performance. The parties agree that irreparable damage would occur in the event that any of the provisions of this Agreement were not performed in accordance with its specific terms or were otherwise breached. Each of the parties agrees that, in the event of any breach or threatened breach by such party of any covenant or obligation contained in this Agreement, the other parties hereto shall be entitled (in addition to any other remedy that may be available to it, including monetary damages) to seek and obtain (a) a decree or order of specific performance to enforce the observance and performance of such covenant or obligation, and (b) an injunction restraining such breach or threatened breach.

6.11 Counterparts and Signature. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original but all of which together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each of the parties hereto and delivered to the other parties, it being understood that all parties need not sign the same counterpart. This Agreement may be executed and delivered by facsimile or “PDF” transmission.

6.12 Interpretation. When reference is made in this Agreement to a Section, such reference shall be to a Section of this Agreement unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include”, “includes” or “including” are used in this Agreement, including Attachment A, they shall be deemed to be followed by the words “without limitation.” As used in this Agreement, the term “person” means any individual, corporation, partnership, joint venture, association, trust, limited liability company, unincorporated organization or other entity. As used in this Agreement, references to any “agreement” to which a person is bound means any contract, agreement, instrument, obligation, undertaking, lease, license, arrangement, commitment or understanding, whether written or oral, in each case that is legally binding on such person and as it may be amended or otherwise modified from time to time. As used in this

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Agreement, a “business day” means any day that is not a Saturday, Sunday or other day on which banking institutions are required or authorized by law to be closed in New York, New York. No summary of this Agreement prepared by any party shall affect the meaning or interpretation of this Agreement.

6.13 Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions hereof or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If the final judgment of a court of competent jurisdiction declares that any term or provision hereof is invalid or unenforceable, the parties hereto agree to negotiate in good faith to modify this Agreement so as to come closest to expressing the intention of the invalid or unenforceable term or provision.

[REMAINDER OF PAGE INTENTIONALLY BLANK]

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IN WITNESS WHEREOF, the parties hereto have caused this Stockholders’ Agreement to be duly executed as of the day and year first above written.

TAKEDA AMERICA HOLDINGS, INC.

By:

/s/ Iwaaki Taniguchi

Name:

Iwaaki Taniguchi

Title:

President

[Stockholders’ Agreement -- Parent Signature Page]

/s/ Timothy P. Walbert

Timothy P. Walbert

/s/ Robert J. De Vaere

Robert J. De Vaere

/s/ Timothy C. Melkus

Timothy C. Melkus

/s/ Jeffrey W. Sherman

Jeffrey W. Sherman, M.D.

/s/ Robert Beck

Robert Beck, M.D.

/s/ Michael G. Grey

Michael G. Grey

/s/ John P. McKearn

John P. McKearn, Ph.D.

/s/ Gregory J. Tibbitts

Gregory J. Tibbitts

MEDAREX, INC.

By:

/s/ Christian S. Schade

Name:

Christian S. Schade

Title: CFO

[Stockholders’ Agreement – Stockholders’ Signature Page]

MICRO CAP PARTNERS, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

PALO ALTO FUND II, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

PALO ALTO HEALTHCARE MASTER FUND, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

[Stockholders’ Agreement – Stockholders’ Signature Page]

PALO ALTO HEALTHCARE MASTER FUND II, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

PALO ALTO SMALL CAP MASTER FUND, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

UBTI FREE, L.P.

By:

PALO ALTO INVESTORS, LLC, General Partner

By:

PALO ALTO INVESTORS, LLC Manager

By:

/s/ Mark Shamia

Name:

Mark Shamia

Title: Chief Operating Officer

[Stockholders’ Agreement – Stockholders’ Signature Page]

ATTACHMENT A

Owned Shares

Stockholder	Shares	Options	RSUs	Warrants


Micro Cap Partners, L.P. (*)	1,950,946			283,079
Palo Alto Fund II, L.P. (*)	885,539			66,918
Palo Alto Healthcare Master Fund, L.P. (*)	2,931,029			381,571
Palo Alto Healthcare Master Fund II, L.P. (*)	2,047,136			42,518
Palo Alto Small Cap Master Fund, L.P. (*)	2,341,500			190,719
UBTI Free, L.P. (*)	201,707
Medarex, Inc.	2,624,279
Timothy P. Walbert		107,354	313,000
John P. McKearn	20,000	116,840
Robert J. De Vaere	10,401	55,235	154,000
Jeffrey W. Sherman		47,091	83,000
Timothy C. Melkus	2,714	31,207	68,000
Michael G. Grey	40,000	40,411
Robert Beck		36,841
Gregory J. Tibbitts		16,250

US1DOCS 7167486v3

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