17. Legal Proceedings  Securities Class Action  On July 30, 2019, plaintiff Linda Rosi (Rosi) filed a putative class action complaint captioned Rosi v. Aclaris Therapeutics, Inc., et al. in the U.S. District Court for the Southern District of New York against the Company and certain of its executive officers. The complaint alleges that the defendants violated federal securities laws by, among other things, failing to disclose an alleged likelihood that regulators would scrutinize advertising materials related to ESKATA and find that the materials minimized the risks or overstated the efficacy of the product. The complaint seeks unspecified compensatory damages on behalf of Rosi and all other persons and entities that purchased or otherwise acquired the Companys securities between May 8, 2018 and June 20, 2019.  On September 5, 2019, an additional plaintiff, Robert Fulcher (Fulcher), filed a substantially identical putative class action complaint captioned Fulcher v. Aclaris Therapeutics, Inc., et al. in the same court against the same defendants.  On November 6, 2019, the court consolidated the Rosi and Fulcher actions (together, the Consolidated Securities Action) and appointed Fulcher lead plaintiff for the putative class.  On January 24, 2020, Fulcher filed a consolidated amended complaint in the Consolidated Securities Action, naming two additional executive officers as defendants, extending the putative class period to August 12, 2019, and adding allegations concerning, among other things, alleged statements and omissions throughout the putative class period concerning ESKATAs risks, tolerability and effectiveness. The defendants filed a motion to dismiss the consolidated amended complaint on April 17, 2020. Fulcher filed an opposition to the defendants motion on June 15, 2020, and the defendants filed a reply to such opposition on August 4, 2020. The motion remains under judicial consideration.  The Company and the other defendants dispute plaintiffs claims in the Consolidated Securities Action and intend to defend the matter vigorously. At this time, the Company cannot reasonably predict the outcome or estimate potential losses, if any, that could result from this matter.  Stockholder Derivative Action  On November 15, 2019, plaintiff Keith Allred (Allred) filed a derivative stockholder complaint captioned Allred v. Walker et al. in the U.S. District Court for the Southern District of New York against certain of the Companys directors and executive officers. The complaint alleges that the defendants, among other things, breached their fiduciary duties as directors and/or officers in connection with the claims alleged in the Consolidated Securities Action. The complaint seeks, among other things, unspecified compensatory damages on behalf of the Company.  On November 25, 2019, an additional plaintiff, Bruce Brown (Brown), filed a substantially identical complaint captioned Brown v. Walker et al. in the same court against the same defendants.  On December 12, 2019, the court consolidated the Allred and Brown actions under the caption In re Aclaris Therapeutics, Inc. Derivative Litigation (the Consolidated Derivative Action) and directed that future derivative cases filed in or transferred to the court arising out of substantially the same transactions or events be similarly consolidated. Thereafter, on January 11, 2020, the court stayed  subject to certain conditions  all deadlines in the Consolidated Derivative Action pending resolution of the defendants then-anticipated motion to dismiss the Consolidated Securities Action.  The defendants dispute plaintiffs claims in the Consolidated Derivative Action and intend to defend the matter vigorously. At this time, the Company cannot reasonably predict the outcome or estimate potential losses, if any, that could result from this matter.