X0306 4 2021-02-02 0 0001599901 Avidity Biosciences, Inc. RNA 0001819159 Kim Jae B. C/O AVIDITY BIOSCIENCES, INC. 10975 N. TORREY PINES RD., SUITE 150 LA JOLLA CA 92037 0 1 0 0 Chief Medical Officer Stock Option (Right to Buy) 22.34 2021-02-02 4 A 0 82000 0.00 A 2031-02-01 Common Stock 82000 82000 D 1/48th of the total number of shares subject to the options shall vest on each monthly anniversary of January 1, 2021 (the "Vesting Commencement Date"), subject to the Reporting Person's continuous service to the Issuer on each such vesting date, so that the options shall be fully vested on the fourth anniversary of the Vesting Commencement Date. /s/ John W. Wallen III, Ph.D., J.D., Attorney-in-Fact 2021-02-04