X0306 4 2019-07-02 0 0001557746 Aclaris Therapeutics, Inc. ACRS 0001751167 Gordon David N. C/O ACLARIS THERAPEUTICS, INC. 640 LEE ROAD, SUITE 200 WAYNE PA 19087 0 1 0 0 Chief Medical Officer Common Stock 2019-07-02 4 M 0 6000 A 6000 D Common Stock 2019-07-02 4 F 0 1648 2.34 D 4352 D Restricted Stock Units 2019-07-02 4 M 0 6000 0.00 D Common Stock 6000 18000 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 the restricted stock units being reported in this Form 4. The shares underlying these restricted stock units vest over a period of four years, with 25% vesting on the first, second, third and fourth anniversaries of the date of grant, beginning on July 2, 2019 and subject to the reporting person's continuous service with the issuer as of the applicable vesting date. /s/ Mark Ballantyne, Attorney-in-fact 2019-07-03