X0306 4 2016-12-18 0 0001557746 Aclaris Therapeutics, Inc. ACRS 0001654301 Powala Christopher C/O ACLARIS THERAPEUTICS, INC. 101 LINDENWOOD DRIVE, SUITE 400 MALVERN PA 19355 0 1 0 0 Chief Operating Officer Common Stock 2016-12-18 4 M 0 1625 A 132059 D Common Stock 2016-12-18 4 F 0 494 31.25 D 131565 D Common Stock 130434 I By Trust Restricted Stock Units 2016-12-18 4 M 0 1625 0.00 D Common Stock 1625 4875 D Restricted stock units convert into common stock on a one-for-one basis. 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. These shares are held by the Christopher V. Powala Aclaris Irrevocable Trust, for which Mr. Powala serves as trustee. On December 18, 2015, the reporting person was granted 6,500 restricted stock units, vesting in four equal annual installments beginning on December 18, 2016, subject to the reporting person's continuous service with the issuer as of the applicable vesting date. /s/ Brian F. Leaf, Attorney-in-fact 2016-12-20