X0407 4 2023-07-01 0 0001557746 Aclaris Therapeutics, Inc. ACRS 0001761167 Cawkwell Gail C/O ACLARIS THERAPEUTICS, INC. 640 LEE ROAD, SUITE 200 WAYNE PA 19087 0 1 0 0 Chief Medical Officer 0 Common Stock 2023-07-01 4 M 0 15000 A 15000 D Common Stock 2023-07-01 4 F 0 5407 10.37 D 9593 D Restricted Stock Units 2023-07-01 4 M 0 15000 0.00 D Common Stock 15000 45000 D Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer. The transaction reported represents the withholding of shares by the issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting and settlement of restricted stock units described in this Form 4. The shares underlying these restricted stock units vest in four equal annual installments beginning on July 1, 2023, subject to the Reporting Person's continuous service with the Issuer as of the applicable vesting date. /s/ Mark Ballantyne, Attorney-in-Fact 2023-07-05