X0306 4 2021-04-16 1 0001175505 FIVE PRIME THERAPEUTICS, INC. FPRX 0001693564 Lyons-Williams Lori 111 OYSTER POINT BOULEVARD SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Stock Option (right to buy) 6.30 2021-04-16 4 D 0 25000 D Common Stock 25000 0 D Stock Option (right to buy) 4.14 2021-04-16 4 D 0 20000 D Common Stock 20000 0 D 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, immediately prior to the effective time of the Merger, each option to purchase shares of common stock of the Company, par value $0.001 per share ("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) $38.00 minus (B) the exercise price payable per share under such option. Not applicable. /s/ Francis Sarena, Attorney-in-fact 2021-04-19