X0306 4 2022-06-17 0 0001290149 Sierra Oncology, Inc. SRRA 0001389147 DILLY STEPHEN GEORGE C/O SIERRA ONCOLOGY, INC. 1820 GATEWAY DRIVE, SUITE 110 SAN MATEO CA 94404 1 1 0 0 CEO and President Stock Option (Right to Buy) 12.15 2022-06-17 4 A 0 65000 0.00 A 2022-06-17 2030-08-12 Common Stock 65000 65000 D On August 12, 2020, the Reporting Person was granted an option to purchase 260,000 shares of common stock. The option vests based on the satisfaction by Issuer of certain performance criteria. The achievement of one of the performance criteria resulted in vesting of the option as to 65,000 shares. /s/ Mary Christina Thomson, Attorney-In-Fact for Stephen George Dilly 2022-06-17