X0306 4 2022-02-09 0 0001557746 Aclaris Therapeutics, Inc. ACRS 0001604457 Walker Neal C/O ACLARIS THERAPEUTICS, INC. 640 LEE ROAD, SUITE 200 WAYNE PA 19087 1 1 0 0 President and CEO Common Stock 2022-02-09 4 S 0 3595 12.6602 D 1239387 D Shares sold to satisfy withholding tax obligations upon the delivery of shares of common stock for restricted stock units that vested on February 1, 2022 pursuant to preexisting sell-to-cover elections. The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $12.6601 to $12.6610, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Mark Ballantyne, Attorney-in-Fact 2022-02-11