UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No. 1)¹

Five Prime Therapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.001

(Title of Class of Securities)

33830X104

(CUSIP Number)

March 4, 2021

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐

Rule 13d-1(b)

☒

Rule 13d-1(c)

☐

Rule 13d-1(d)

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. 33830X104

NAME OF REPORTING PERSON

Biotechnology Value Fund, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

3,372,098

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

3,372,098

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

3,372,098

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

7.3%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF I GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

3,372,098

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

3,372,098

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

3,372,098

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

7.3%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

Biotechnology Value Fund II, L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

2,484,643

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

2,484,643

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,484,643

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

5.4%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF II GP LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

2,484,643

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

2,484,643

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,484,643

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

5.4%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

Biotechnology Value Trading Fund OS LP

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

405,344

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

405,344

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

405,344

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF Partners OS Ltd.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

405,344

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

405,344

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

405,344

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF GP HOLDINGS LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

5,856,741

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

5,856,741

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

5,856,741

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

12.8%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF Partners L.P.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

6,338,678

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

6,338,678

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

6,338,678

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

13.8%

TYPE OF REPORTING PERSON

PN, IA

CUSIP No. 33830X104

NAME OF REPORTING PERSON

BVF Inc.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

6,338,678

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

6,338,678

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

6,338,678

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

13.8%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

NAME OF REPORTING PERSON

Mark N. Lampert

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

United States

NUMBER OF

SOLE VOTING POWER

BENEFICIALLY

0 shares

OWNED BY

SHARED VOTING POWER

EACH

REPORTING

6,338,678

PERSON WITH

SOLE DISPOSITIVE POWER

0 shares

SHARED DISPOSITIVE POWER

6,338,678

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

6,338,678

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

13.8%

TYPE OF REPORTING PERSON

CUSIP No. 33830X104

Item 1(a).

Name of Issuer:

Five Prime Therapeutics, Inc., a Delaware corporation (the “Issuer”).

Item 1(b).

Address of Issuer’s Principal Executive Offices:

111 Oyster Point Boulevard

South San Francisco, California 94080

Item 2(a).

Name of Person Filing

Item 2(b).

Address of Principal Business Office or, if None, Residence

Item 2(c).

Citizenship

Biotechnology Value Fund, L.P. (“BVF”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF I GP LLC (“BVF GP”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Fund II, L.P. (“BVF2”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF II GP LLC (“BVF2 GP”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Trading Fund OS LP (“Trading Fund OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF Partners OS Ltd. (“Partners OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF GP Holdings LLC (“BVF GPH”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Partners L.P. (“Partners”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

CUSIP No. 33830X104

BVF Inc.

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: United States

Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting Persons.”

Item 2(d).

Title of Class of Securities:

Common Stock, par value $0.001 (the “Shares”).

Item 2(e).

CUSIP Number:

33830X104

Item 3.

If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

	/x/	Not applicable.

(a)	/ /	Broker or dealer registered under Section 15 of the Exchange Act.

(b)	/ /	Bank as defined in Section 3(a)(6) of the Exchange Act.

(c)	/ /	Insurance company as defined in Section 3(a)(19) of the Exchange Act.

(d)	/ /	Investment company registered under Section 8 of the Investment Company Act.

(e)	/ /	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E).

(f)	/ /	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F).

(g)	/ /	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G).

(h)	/ /	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act.

(i)	/ /	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act.

(j)	/ /	Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

(k)	/ /	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Rule 240.13d-1(b)(1)(ii)(J), please specify the type of institution: ____

CUSIP No. 33830X104

Item 4.

Ownership

(a)

Amount beneficially owned:

As of the close of business on March 8, 2021, (i) BVF beneficially owned 3,372,098 Shares, (ii) BVF2 beneficially owned 2,484,643 Shares and (iii) Trading Fund OS beneficially owned 405,344 Shares.

BVF GP, as the general partner of BVF, may be deemed to beneficially own the 3,372,098 Shares beneficially owned by BVF.

BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 2,484,643 Shares beneficially owned by BVF2.

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 405,344 Shares beneficially owned by Trading Fund OS.

BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 5,856,741 Shares beneficially owned in the aggregate by BVF and BVF2.

Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 6,338,678 Shares beneficially owned in the aggregate by BVF, BVF2, Trading Fund OS, and a certain Partners managed account (the “Partners Managed Account”), including 76,593 Shares held in the Partners Managed Account.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 6,338,678 Shares beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 6,338,678 Shares beneficially owned by BVF Inc.

The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners Managed Account, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.

(b)

Percent of class:

The following percentages are based on 45,939,508 Shares outstanding as of March 1, 2021, which is the total number of Shares outstanding as disclosed in that certain Agreement and Plan of Merger, dated as of March 4, 2021, by and among Amgen Inc., Franklin Acquisition Sub, Inc. and the Issuer filed as Exhibit 2.1 to the Issuer’s Current Report on Form 8-K with the Securities and Exchange Commission on March 4, 2021.

CUSIP No. 33830X104

As of the close of business on March 8, 2021, (i) BVF beneficially owned approximately 7.3% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 5.4% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 7.3% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 5.4% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 12.8% of the outstanding Shares and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 13.8% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account).

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or to direct the vote

See Cover Pages Items 5-9.

(ii)

Shared power to vote or to direct the vote

See Cover Pages Items 5-9.

(iii)

Sole power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

(iv)

Shared power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

Item 5.

Ownership of Five Percent or Less of a Class.

Not Applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

BVF GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF. BVF2 GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF2. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by Trading Fund OS and the Partners Managed Account.

Item 7.

Identification and Classification of the Subsidiary That Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not Applicable.

Item 8.

Identification and Classification of Members of the Group.

See Exhibit 99.1 to the Schedule 13G filed with the Securities and Exchange Commission on February 1, 2021.

CUSIP No. 33830X104

Item 9.

Notice of Dissolution of Group.

Not Applicable.

Item 10.

Certifications.

By signing below each of the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

CUSIP No. 33830X104

SIGNATURE

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

Dated: March 8, 2021

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 N. 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 N. 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 N. 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
	Mark N. Lampert
	President

FIVE PRIME THERAPEUTICS, INC. SC 13G/A