X0306 4 2018-02-01 0 0001557746 Aclaris Therapeutics, Inc. ACRS 0001604457 Walker Neal C/O ACLARIS THERAPEUTICS, INC. 101 LINDENWOOD DRIVE, SUITE 400 MALVERN PA 19355 1 1 0 0 President and CEO Stock option (right to buy) 22.09 2018-02-01 4 A 0 151200 0.00 A 2028-01-31 Common Stock 151200 151200 D Restricted stock units 2018-02-01 4 A 0 43200 0.00 A Common Stock 43200 43200 D The option will vest over a period of four years, with 25% of the shares underlying the option vesting on the first, second, third and fourth anniversaries of the date of grant. Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer. The shares underlying these restricted stock units vest in four equal annual installments beginning on February 1, 2019, subject to the reporting person's continuous service with the issuer as of the applicable vesting date. /s/ Brian F. Leaf, Attorney-in-fact 2018-02-05