Aclaris Therapeutics, Inc. provides an update on the status of certain of its clinical programs and on its research and development (R&D) operations. Zunsemetinib, an Investigational Oral MK2 Inhibitor. Aclaris initiated study activities and began activating sites in December 2021 in the following two studies: ATI-450-RA-202: Phase 2b clinical trial of zunsemetinib in subjects with moderate to severe rheumatoid arthritis (RA).

This is Aclaris' second Phase 2 clinical trial of zunsemetinib in subjects with moderate to severe RA, and is primarily designed to assess the efficacy of multiple doses of zunsemetinib to aid in the selection of an optimal dose to progress in future development. ATI-450-HS-201: Phase 2a clinical trial of zunsemetinib in subjects with moderate to severe hidradenitis suppurative (HS). ATI-2138-PKPD-101: Aclaris completed dosing of the first cohort of subjects in its Phase 1 single ascending dose clinical trial of ATI-2138, its investigational oral ITK/TXK/JAK3 inhibitor, in healthy subjects, in December 2021.

This is Aclaris' first-in-human trial of ATI-2138, and is designed to assess the safety and tolerability of ATI-2138 in healthy subjects and provide dosing guidance for future clinical trials. ATI-450-RA-202 is a Phase 2b randomized, multicenter, double-blind, parallel group, placebo-controlled, dose ranging trial to investigate the efficacy, safety, tolerability, pharmacokinetics and pharmacodynamics of multiple doses (20mg and 50mg BID) of zunsemetinib in combination with methotrexate in subjects with moderate to severe RA. This trial will consist of a 12-week treatment period and a 30-day follow-up period, and will seek to enroll subjects in the United States and in multiple countries in Europe.

The primary endpoint is the proportion of subjects achieving American College of Rheumatology 20% (ACR20) at week 12. ATI-450-HS-201: ATI-450-HS-201 is a Phase 2a randomized, multicenter, double-blind, placebo-controlled trial to investigate the efficacy, safety, tolerability, pharmacokinetics and pharmacodynamics of zunsemetinib (50mg BID) in subjects with moderate to severe HS. This trial will consist of a 12-week treatment period and a 30-day follow-up period, and will seek to enroll subjects in the United States.

The primary endpoint is the change in inflammatory nodule and abscess count at week 12.