X0508 4 2026-01-21 0 0001599901 Avidity Biosciences, Inc. RNA 0001862121 McCarthy Teresa C/O AVIDITY BIOSCIENCES, INC. 3020 CALLAN RD. SAN DIEGO CA 92121 0 1 0 0 Chief Human Resources Officer 1 Common Stock 2026-01-21 4 S 0 1476 72.45 D 115391 D Common Stock 2026-01-21 4 S 0 1453 72.45 D 113938 D Represents the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of RSUs on January 20, 2026 and the sale of the resulting shares of common stock on January 21, 2026. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell-to-cover" transaction and does not represent a discretionary trade by the Reporting Person. The Reporting Person has executed an instruction letter for the automatic sale of such "sell-to-cover" shares, intended to satisfy the affirmative defense conditions of Rule 10b5-1. /s/ John B. Moriarty, Jr., J.D., Attorney-in-Fact 2026-01-23