SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 3)¹

XOMA Corporation

(Name of Issuer)

Common Stock, $0.0075 par value

(Title of Class of Securities)

98419J 206

(CUSIP Number)

JAMES KRATKY

BVF PARTNERS L.P.

44 Montgomery St., 40th Floor

San Francisco, California 94104

(415) 525-8890

ADAM W. FINERMAN, ESQ.

OLSHAN FROME WOLOSKY LLP

1325 Avenue of the Americas

New York, New York 10019

(212) 451-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

February 11, 2020

(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 §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-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 § 240.13d-7 for other parties to whom copies are to be sent. 

1              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 disclosures provided in a prior cover page.

The information required on 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).

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BIOTECHNOLOGY VALUE FUND, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			WC
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					1,803,635 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					1,803,635 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,803,635 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			17.3% (1)
	14	TYPE OF REPORTING PERSON
			PN

(1) Includes 655,959 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 2,313,000 Shares underlying certain Series X Convertible Preferred Stock as described below in Item 5.

2

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF I GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					1,803,635 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					1,803,635 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,803,635 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			17.3% (1)
	14	TYPE OF REPORTING PERSON
			OO

(1) Includes 655,959 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 2,313,000 Shares underlying certain Series X Convertible Preferred Stock as described below in Item 5.

3

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BIOTECHNOLOGY VALUE FUND II, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			WC
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					1,700,127 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					1,700,127 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,700,127 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			16.4% (1)
	14	TYPE OF REPORTING PERSON
			PN

(1) Includes 596,813 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 1,506,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

4

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF II GP LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					1,700,127 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					1,700,127 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			1,700,127 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			16.4% (1)
	14	TYPE OF REPORTING PERSON
			OO

(1) Includes 596,813 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 1,506,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

5

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BIOTECHNOLOGY VALUE TRADING FUND OS, L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			WC
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			CAYMAN ISLANDS
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					159,537 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					159,537 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			159,537 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			1.6% (1)
	14	TYPE OF REPORTING PERSON
			PN

(1) Excludes 412,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

6

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF PARTNERS OS LTD.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			CAYMAN ISLANDS
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					159,537 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					159,537 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			159,537 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			1.6% (1)
	14	TYPE OF REPORTING PERSON
			CO

(1) Excludes 412,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

7

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF GP HOLDINGS LLC
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					3,503,762 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					3,503,762 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			3,503,762 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			31.8% (1)
	14	TYPE OF REPORTING PERSON
			OO

(1) Includes 1,252,772 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 3,819,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

8

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF PARTNERS L.P.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					3,895,177 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					3,895,177 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			3,895,177 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			35.4% (1)
	14	TYPE OF REPORTING PERSON
			PN, IA

(1) Includes 1,252,772 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 5,003,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

9

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			BVF INC.
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			DELAWARE
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					3,895,177 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					3,895,177 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			3,895,177 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			35.4% (1)
	14	TYPE OF REPORTING PERSON
			CO

(1) Includes 1,252,772 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 5,003,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

10

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			MARK N. LAMPERT
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
			AF
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			USA
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					- 0 -
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					3,895,177 (1)
PERSON WITH			9	SOLE DISPOSITIVE POWER
					- 0 -
			10	SHARED DISPOSITIVE POWER
					3,895,177 (1)
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			3,895,177 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			35.4% (1)
	14	TYPE OF REPORTING PERSON
			IN

(1) Includes 1,252,772 Shares currently issuable upon the conversion of certain Series Y Convertible Preferred Stock and excludes 5,003,000 Shares underlying Series X Convertible Preferred Stock as described below in Item 5.

11

CUSIP No. 98419J 206

	1	NAME OF REPORTING PERSON
			MATTHEW D. PERRY
	2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP				(a) ☒
						(b) ☐
	3	SEC USE ONLY
	4	SOURCE OF FUNDS
	5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)				☐
	6	CITIZENSHIP OR PLACE OF ORGANIZATION
			USA
NUMBER OF			7	SOLE VOTING POWER
SHARES
BENEFICIALLY					36,837 (1)
OWNED BY			8	SHARED VOTING POWER
EACH
REPORTING					- 0 -
PERSON WITH			9	SOLE DISPOSITIVE POWER
					36,837 (1)
			10	SHARED DISPOSITIVE POWER
					- 0 -
	11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
			36,837 (1)
	12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES				☐
	13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
			Less than 1% (1)
	14	TYPE OF REPORTING PERSON
			IN

(1) Includes 25,038 Shares issuable on the exercise of certain options that are currently exercisable.

12

CUSIP No. 98419J 206

The following constitutes Amendment No. 3 to the Schedule 13D filed by the undersigned (the “Amendment No. 3”). This Amendment No. 3 amends the Schedule 13D as specifically set forth herein.

Item 2. Identity and Background.

Item 2 is hereby amended and restated to read as follows:

(a)       This statement is filed by:

(i) Biotechnology Value Fund, L.P., a Delaware limited partnership (“BVF”);

(ii) BVF I GP LLC, a Delaware limited liability company (“BVF GP”), which serves as general partner of BVF;

(iii) Biotechnology Value Fund II, L.P., a Delaware limited partnership (“BVF2”);

(iv) BVF II GP LLC, a Delaware limited liability company (“BVF2 GP”), which serves as general partner of BVF2;

(v) Biotechnology Value Trading Fund OS LP, a Cayman Islands limited partnership (“Trading Fund OS”);

(vi) BVF Partners OS Ltd., a Cayman Islands limited liability company (“Partners OS”), which serves as general partner of Trading Fund OS;

(vii) BVF GP Holdings LLC, a Delaware limited liability company (“BVF GPH”), which is the sole member of each of BVF GP and BVF2 GP;

(viii) BVF Partners L.P., a Delaware limited partnership (“Partners”), which serves as the investment manager of each of BVF, BVF2, Trading Fund OS and certain managed accounts (the “Partners Managed Accounts”), and as the sole member of Partners OS;

(ix) BVF Inc., a Delaware corporation, which serves as general partner of Partners and the managing member of BVF GPH;

(x) Mark N. Lampert, who serves as the sole officer and director of BVF Inc.; and

(xi) Matthew D. Perry, the President of Partners and member of the Issuer’s Board of Directors.

13

CUSIP No. 98419J 206

Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting Persons.” Each of the Reporting Persons is party to that certain Joint Filing Agreement, as further described in Item 6. Accordingly, the Reporting Persons are hereby filing a joint Schedule 13D.

(b)       The business address of BVF, BVF GP, BVF2, BVF2 GP, BVF GPH, Partners, BVF Inc. Mr. Lampert and Mr. Perry is 44 Montgomery St., 40^th Floor, San Francisco, California 94104. The business address of Trading Fund OS and Partners OS is PO Box 309 Ugland House, Grand Cayman, KY1-1104, Cayman Islands.

(c)       The principal business of each of BVF, BVF2, and Trading Fund OS is investing in securities. The principal business of BVF GP, BVF2 GP, and Partners OS is serving as the general partner of BVF, BVF2, and Trading Fund OS, respectively. The principal business of BVF GPH is serving as the sole member of each of BVF GP and BVF2 GP. The principal business of Partners is serving as the investment manager of each of BVF, BVF2, Trading Fund OS and the Partners Managed Accounts, and the sole member of Partners OS. The principal business of BVF Inc. is serving as the general partner of Partners and the managing member of BVF GPH. Mr. Lampert is the sole officer and director of BVF Inc. Mr. Perry is the President of Partners.

(d)       No Reporting Person has, during the last five years, been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e)       No Reporting Person has, during the last five years, been 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.

(f)       Messrs. Lampert and Perry are citizens of the United States of America.

Item 5. Interest in Securities of the Issuer.

Items 5(a)-(c) are hereby amended and restated to read as follows:

(a)       The aggregate percentage of Shares reported owned by each person named herein is based on a denominator that is the sum of: (i) 8,757,515 Shares outstanding as of November 29, 2019, which is the total number of Shares outstanding as reported in the Issuer’s Prospectus Supplement on Form 424B5 filed with the SEC on December 2, 2019, (ii) 1,000,000 Shares issued pursuant to the Rights Offering as advised by the Issuer, (iii) certain or all of the 1,252,772 Shares underlying the Series Y Preferred Stock and (iv) with respect to Mr. Perry, 25,038 Shares issuable on the exercise of certain options.

14

CUSIP No. 98419J 206

As of the date hereof, the Reporting Persons hold 5,003 shares of Series X Preferred Stock, convertible into an aggregate of 5,003,000 Shares. Each share of Series X Preferred Stock is convertible into 1,000 Shares. The Series X Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), more than 19.99% of the Shares outstanding immediately after giving effect to such conversion (the “Series X Beneficial Ownership Limitation”). As of the date hereof, the Series X Beneficial Ownership Limitation, limits the aggregate conversion of the Series X Preferred Stock by the Reporting Persons to zero out of the 5,003,000 Shares underlying the Series X Preferred Stock.

As of the date hereof, the Reporting Persons hold 1,252.772 shares of Series Y Preferred Stock, convertible into an aggregate of 1,252,772 Shares. Each share of Series Y Preferred Stock is convertible into 1,000 Shares based on a conversion price of $13.00 per Share. The Series Y Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 50.0% of the Shares outstanding immediately after giving effect to such conversion (the “Series Y Beneficial Ownership Limitation”). As of the date hereof, the Series Y Beneficial Ownership Limitation does not limit the aggregate conversion of the Series Y Preferred Stock by the Reporting Persons.

As of the date hereof, (i) BVF beneficially owned 1,803,635 Shares, including 655,959 Shares issuable upon the conversion of certain Series Y Preferred Stock and excluding 2,313,000 Shares issuable upon the conversion of certain Series X Preferred Stock, representing percentage ownership of approximately 17.3% of the Shares outstanding, (ii) BVF2 beneficially owned 1,700,127 Shares, including 596,813 Shares issuable upon the conversion of certain Series Y Preferred Stock and excluding 1,506,000 Shares issuable upon the conversion of certain Series X Preferred Stock, representing percentage ownership of approximately 16.4% of the Shares outstanding, (iii) Trading Fund OS beneficially owned 159,537 Shares, excluding 412,000 Shares issuable upon the conversion of certain Series X Preferred Stock, representing percentage ownership of approximately 1.6% of the Shares outstanding, and (iv) 231,878 Shares were held in the Partners Managed Accounts, excluding 772,000 Shares issuable upon the conversion of certain Series X Preferred Stock, representing percentage ownership of approximately 2.4% of the Shares outstanding.

BVF GP, as the general partner of BVF, may be deemed to beneficially own the 1,803,635 Shares beneficially owned by BVF, representing percentage ownership of approximately 17.3% of the Shares outstanding.

BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 1,700,127 Shares beneficially owned by BVF2, representing percentage ownership of approximately 16.4% of the Shares outstanding.

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 159,537 Shares beneficially owned by Trading Fund OS, representing percentage ownership of approximately 1.6% of the Shares outstanding.

15

CUSIP No. 98419J 206

BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 3,503,762 Shares beneficially owned in the aggregate by BVF and BVF2, representing percentage ownership of approximately 31.8% of the Shares outstanding.

Partners, as the investment manager of BVF, BVF2, Trading Fund OS and the Partners Managed Accounts and the sole member of Partners OS, may be deemed to beneficially own the 3,895,177 Shares beneficially owned in the aggregate by BVF, BVF2, Trading Fund OS, and held in the Partners Managed Accounts, representing percentage ownership of approximately 35.4% of the Shares outstanding.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 3,895,177 Shares beneficially owned by Partners, representing percentage ownership of approximately 35.4% of the Shares outstanding.

Mr. Lampert, as a director and officer of BVF Inc. may be deemed to beneficially own the 3,895,177 Shares beneficially owned by BVF Inc., representing percentage ownership of approximately 35.4% of the Shares outstanding.

As of the date hereof, Mr. Perry beneficially owned 36,837 Shares, including 25,038 Shares issuable on the exercise of certain options that are currently exercisable, representing percentage ownership of less than 1%.

(b)       Each of BVF, BVF2 and Trading Fund OS shares with Partners voting and dispositive power over the Shares each such entity beneficially owns. BVF shares with BVF GP voting and dispositive power over the Shares beneficially owned by BVF. BVF2 shares with BVF2 GP voting and dispositive power over the Shares beneficially owned by BVF2. Each of BVF GP and BVF2 GP shares with BVF GPH voting and dispositive power over the Shares each such entity beneficially owns. Trading Fund OS shares with Partners OS voting and dispositive power over the Shares beneficially owned by Trading Fund OS. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the 3,895,177 Shares they may be deemed to beneficially own with BVF, BVF GP, BVF2, BVF2 GP, Trading Fund OS, Partners OS, BVF GPH and the Partners Managed Accounts.

(c)       The Reporting Persons have not entered into any transactions in the Shares during the past sixty days.

Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.

Item 6 is hereby amended to add the following:

Pursuant to Section 6(c) of the Certificate of Designation of Preferences, Rights and Limitations of Series Y Convertible Preferred Stock, the applicable Reporting Persons have elected to increase the Series Y Beneficial Ownership Limitation to 50% of the number of Shares outstanding after any future conversion of the Series Y Preferred Stock, effective February 11,^, 2020. As such, as of February 11, 2020, the applicable Reporting Persons may be deemed to have beneficial ownership of the Shares underlying the outstanding Series Y Preferred Stock.

16

CUSIP No. 98419J 206

Item 7. Material to be Filed as Exhibits.

Item 7 is hereby amended to add the following exhibit:

99.1 Joint Filing Agreement by and among Biotechnology Value Fund, L.P., BVF I GP LLC, Biotechnology Value Fund II, L.P., BVF II GP, LLC, Biotechnology Value Trading Fund OS LP, BVF Partners OS Ltd., BVF GP Holdings LLC, BVF Partners L.P., BVF Inc., Mark N. Lampert, and Matthew D. Perry, dated February 13, 2020.

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CUSIP No. 98419J 206

SIGNATURES

After reasonable inquiry and to the best of his or its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: February 13, 2020

BIOTECHNOLOGY VALUE FUND, L.P.		BIOTECHNOLOGY VALUE TRADING FUND OS LP
By:	BVF I GP LLC., its general partner	By:	BVF Partners L.P., its investment manager
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			President
BVF I GP LLC
		BVF GP HOLDINGS LLC
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			Chief Executive Officer
BIOTECHNOLOGY VALUE FUND II, L.P.
		BVF PARTNERS L.P.
By:	BVF II GP LLC its general partner
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President
BVF II GP LLC
		BVF INC.
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			President
BVF PARTNERS OS LTD.
		/s/ Mark N. Lampert
By:	BVF Partners L.P., its sole member	MARK N. LAMPERT
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert	/s/ Matthew D. Perry
	Mark N. Lampert	MATTHEW D. PERRY
	President

18

EX-99.1

Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D dated February 13, 2020 (including amendments thereto) with respect to the shares of Common Stock, $0.0075 par value, of XOMA Corporation. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: February 13, 2020

BIOTECHNOLOGY VALUE FUND, L.P.		BIOTECHNOLOGY VALUE TRADING FUND OS LP
By:	BVF I GP LLC., its general partner	By:	BVF Partners L.P., its investment manager
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			President
BVF I GP LLC
		BVF GP HOLDINGS LLC
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			Chief Executive Officer
BIOTECHNOLOGY VALUE FUND II, L.P.
		BVF PARTNERS L.P.
By:	BVF II GP LLC its general partner
		By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark N. Lampert
			President
BVF II GP LLC
		BVF INC.
By:	/s/ Mark N. Lampert
	Mark N. Lampert	By:	/s/ Mark N. Lampert
	Chief Executive Officer		Mark Lampert
			President
BVF PARTNERS OS LTD.
		/s/ Mark N. Lampert
By:	BVF Partners L.P., its sole member	MARK N. LAMPERT
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert	/s/ Matthew D. Perry
	Mark N. Lampert	MATTHEW D. PERRY
	President