Sec Form 4 Filing - Collins Helen Louise @ FIVE PRIME THERAPEUTICS, INC. - 2021-03-31

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Collins Helen Louise 2. Issuer Name and Ticker or Trading Symbol FIVE PRIME THERAPEUTICS, INC. [ FPRX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP and Chief Medical Officer (Last) (First) (Middle) 111 OYSTER POINT BOULEVARD 3. Date of Earliest Transaction (MM/DD/YY) 03/31/2021 (Street) SOUTH SAN FRANCISCO, CA94080 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/31/2021 G V 8,085 D $ 0 69,547 D Common Stock 04/16/2021 A 66,000 ( 1 ) A $ 0 135,547 D Common Stock 04/16/2021 D( 2 ) 135,547 D $ 38 0 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Employee Stock Option (right to buy) $ 37.89 04/16/2021 D 60,000 ( 3 ) ( 4 ) Common Stock 60,000 ( 3 ) 0 D Employee Stock Option (right to buy) $ 18.69 04/16/2021 D 50,000 ( 3 ) ( 4 ) Common Stock 50,000 ( 3 ) 0 D Employee Stock Option (right to buy) $ 11.97 04/16/2021 D 58,000 ( 3 ) ( 4 ) Common Stock 58,000 ( 3 ) 0 D Employee Stock Option (right to buy) $ 5.78 04/16/2021 D 20,000 ( 3 ) ( 4 ) Common Stock 20,000 ( 3 ) 0 D Employee Stock Option (right to buy) $ 5.25 04/16/2021 D 90,000 ( 3 ) ( 4 ) Common Stock 90,000 ( 3 ) 0 D Employee Stock Option (right to buy) $ 5.25 04/16/2021 D 90,000 ( 3 ) ( 4 ) Common Stock 90,000 ( 3 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Collins Helen Louise 111 OYSTER POINT BOULEVARD SOUTH SAN FRANCISCO, CA94080 EVP and Chief Medical Officer Signatures /s/ Francis Sarena, Attorney-in-fact 04/19/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of performance-based restricted Common Stock (as defined below) granted to the reporting person on June 24, 2019 (the "Performance Award"). The performance conditions associated with the Performance Award have not yet occurred. Pursuant to the Merger Agreement (as defined below), immediately prior to the effective time of the Merger (as defined below), the Performance Award was deemed to have vested and each share of Common Stock underlying the Performance Award was converted into the right to receive the Offer Price (as defined below) in cash, without interest, minus any applicable withholding taxes. ( 2 )Pursuant to the Agreement and Plan of Merger, dated March 4, 2021 (the "Merger Agreement"), by and among the Five Prime Therapeutics, Inc. (the "Company"), Amgen Inc. ("Parent") and Franklin Acquisition Sub, Inc., a wholly owned subsidiary of Parent ("Purchaser"), Purchaser merged with and into the Company, with the Company surviving as a wholly owned subsidiary of Parent (the "Merger"), effective as of April 16, 2021. Pursuant to the Merger Agreement, each issued and outstanding share of common stock of the Company, par value $0.001 per share ("Common Stock"), was converted into the right to receive $38.00 per share (the "Offer Price") in cash, without interest, minus any applicable withholding taxes. ( 3 )Pursuant to the Merger Agreement, immediately prior to the effective time of the Merger, each option to purchase shares of Common Stock granted by the Company that was then outstanding and unexercised was cancelled and converted into the right to receive an amount in cash equal to the product of (x) the total number of shares of Common Stock subject to such option multiplied by (y) the excess, if any, of (A) the Offer Price minus (B) the exercise price payable per share under such option. ( 4 )Not applicable.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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