Biotechnology Value Fund L P SC 13G Five Prime Therapeutics Inc

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

Five Prime Therapeutics, Inc.

 (Name of Issuer)

Common Stock, $0.001 par value

 (Title of Class of Securities)

33830X 10 4

 (CUSIP Number)

February 7, 2014

 (Date of Event Which Requires Filing of this Statement)

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

 o  Rule 13d-1(b)

 x  Rule 13d-1(c)

 o  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 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).

CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON Biotechnology Value Fund, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER 614,456
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER 614,456
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 614,456
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 3.1%
12	TYPE OF REPORTING PERSON PN

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CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON Biotechnology Value Fund II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER 347,941
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER 347,941
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 347,941
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 1.8%
12	TYPE OF REPORTING PERSON PN

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CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON Investment 10, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Illinois
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER  173,603
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER  173,603
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON  173,603
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) Less than 1%
12	TYPE OF REPORTING PERSON OO

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CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON BVF Partners L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER 1,136,000
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER 1,136,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,136,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 5.7%
12	TYPE OF REPORTING PERSON PN, IA

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CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON BVF Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER 1,136,000
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER 1,136,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,136,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 5.7%
12	TYPE OF REPORTING PERSON CO

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CUSIP NO. 33830X 10 4

1	NAME OF REPORTING PERSON Mark N. Lampert
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) x   (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	5	SOLE VOTING POWER 0 shares
	6	SHARED VOTING POWER 1,136,000
	7	SOLE DISPOSITIVE POWER 0 shares
	8	SHARED DISPOSITIVE POWER 1,136,000
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,136,000
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES		¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 5.7%
12	TYPE OF REPORTING PERSON IN

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CUSIP NO. 33830X 10 4

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:

Two Corporate Drive

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”)

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

Citizenship: Delaware

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

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

Citizenship: Delaware

Investment 10, L.L.C. (“ILL10”)

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

Citizenship: Illinois

BVF Partners L.P. (“Partners”)

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

Citizenship: Delaware

BVF Inc.

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

900 North Michigan Avenue, Suite 1100

Chicago, Illinois 60611

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

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CUSIP NO. 33830X 10 4

Item 2(e). CUSIP Number:

33830X 10 4

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: ____

Item 4. Ownership

(a) Amount beneficially owned:

As of the close of business on the date hereof, (i) BVF beneficially owned 614,456 shares of Common Stock, (ii) BVF2 beneficially owned 347,941 shares of Common Stock, and (iii) ILL10 beneficially owned 173,603 shares of Common Stock.

Partners, as the general partner of BVF and BVF2 and the investment adviser of ILL10 may be deemed to beneficially own 1,136,000 shares of Common Stock beneficially owned in the aggregate by BVF, BVF2 and ILL10.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 1,136,000 shares of Common Stock beneficially owned by Partners.

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CUSIP NO. 33830X 10 4

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 1,136,000 shares of Common Stock 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 of Common Stock owned by another Reporting Person.  Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the shares of Common Stock beneficially owned by BVF, BVF2 and ILL10 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 19,818,008 shares of Common Stock outstanding as of February 10, 2014, as disclosed in the Issuer’s Prospectus filed pursuant to Rule 424(b)(4) with the Securities and Exchange Commission on February 7, 2014.

As of the close of business on the date hereof, (i) BVF beneficially owned approximately 3.1% of the outstanding shares of Common Stock, (ii) BVF2 beneficially owned approximately 1.8% of the outstanding shares of Common Stock, (iii) ILL10 beneficially owned less than 1% of the outstanding shares of Common Stock, and (iv) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 5.7% of the outstanding shares of Common Stock.

(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.

Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the shares of Common Stock beneficially owned by BVF, BVF2 and ILL10.

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CUSIP NO. 33830X 10 4

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.

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.

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CUSIP NO. 33830X 10 4

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:  February 14, 2014

BIOTECHNOLOGY VALUE FUND, L.P.
By:	BVF Partners L.P., its general partner
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President
BIOTECHNOLOGY VALUE FUND II, L.P.		BVF PARTNERS L.P.
By:	BVF Partners L.P., its general partner	By:	BVF Inc., its general partner
By:	BVF Inc., its general partner
		By:	/s/ Mark N. Lampert
By:	/s/ Mark N. Lampert		Mark N. Lampert
	Mark N. Lampert		President
	President
		BVF INC.
INVESTMENT 10, L.L.C.		By:	/s/ Mark N. Lampert
			Mark N. Lampert
By:	BVF Partners L.P., its investment manager		President
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President

/s/ Mark N. Lampert

MARK N. LAMPERT

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