X0306 4 2022-03-04 0 0001382101 SUTRO BIOPHARMA, INC. STRO 0001398940 MOLINA ARTURO MD C/O SUTRO BIOPHARMA, INC. 111 OYSTER POINT BLVD. SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Medical Officer Common Stock 2022-03-05 4 M 0 12500 A 42091 D Common Stock 2022-03-05 4 F 0 4355 8.17 D 37736 D Stock Option (right to buy Common Stock) 8.17 2022-03-04 4 A 0 52000 0.00 A 2032-03-03 Common Stock 52000 52000 D Restricted Stock Unit (RSU) 2022-03-04 4 A 0 39000 0.00 A 2026-03-04 Common Stock 39000 39000 D Restricted Stock Unit (RSU) 2022-03-05 4 M 0 12500 0.00 D 2025-03-05 Common Stock 12500 37500 D Each RSU represents a contingent right to receive one (1) share of the issuer's Common Stock upon settlement. Represents the number of shares of Common Stock that have been withheld by the issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of the RSUs and does not represent a sale by the reporting person. The option vests as to 2.0833% of the total shares monthly, beginning on April 4, 2022, with 100% of the total shares vested and exercisable on March 4, 2026, subject to the reporting person's provision of service to the issuer on each vesting date. The RSUs vest as to 1/4th of the total shares annually beginning on March 4, 2023, subject to continued service through each vesting date. The RSUs vest as to 1/4th of the total shares annually beginning on March 5, 2022, subject to continued service through each vesting date. /s/ Edward C. Albini as attorney-in-fact for Arturo Molina, M.D. 2022-03-07