Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * BVF PARTNERS L P/IL	2. Date of Event Requiring Statement (MM/DD/YYYY) 10/1/2019	3. Issuer Name and Ticker or Trading Symbol FIVE PRIME THERAPEUTICS, INC. [FPRX]
(Last)        (First)        (Middle) 44 MONTGOMERY STREET, 40TH FL	4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director                          ___X___ 10% Owner _____ Officer (give title below)        _____ Other (specify below)
(Street) SAN FRANCISCO, CA 94104       (City)              (State)              (Zip)	5. If Amendment, Date Original Filed(MM/DD/YYYY)	6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock, $0.001 par value (1)	2046311	D (2)
Common Stock, $0.001 par value (1)	1662274	D (3)
Common Stock, $0.001 par value (1)	298496	D (4)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:
(1)	This Form 3 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Each of the Reporting Persons is a member of a Section 13(d) group that collectively owns more than 10% of the Issuer's outstanding shares of Common Stock. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein.
(2)	Securities owned directly by BVF. As the general partner of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF.
(3)	Securities owned directly by BVF2. As the general partner of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2.
(4)	Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
BVF PARTNERS L P/IL 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO, CA 94104		X
BIOTECHNOLOGY VALUE FUND L P 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO, CA 94104				See Explanation of Responses
BIOTECHNOLOGY VALUE FUND II LP 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO, CA 94104				See Explanation of Responses
Biotechnology Value Trading Fund OS LP P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN, E9 KY1-1104				See Explanation of Responses
BVF Partners OS Ltd. P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN, E9 KY1-1104				See Explanation of Responses
BVF INC/IL 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO, CA 94104		X
LAMPERT MARK N 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO, CA 94104		X

Signatures
BVF Partners L.P., By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
Biotechnology Value Fund, L.P., By: BVF Partners L.P., its general partner, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
Biotechnology Value Fund II, L.P., By: BVF Partners L.P., its general partner, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
BVF Partners OS Ltd., By: BVF Partners L.P., its sole member, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
Biotechnology Value Trading Fund OS LP, By: BVF Partners L.P., its investment manager, BVF Inc., its general partner, By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
BVF Inc., By: /s/ Mark N. Lampert, President		10/2/2019
**Signature of Reporting Person		Date
/s/ Mark N. Lampert		10/2/2019
**Signature of Reporting Person		Date