ACRS ATI-052 Phase 1a Exceeds Target; 45-Day Half-Life
Aclaris Therapeutics announced positive full results from its Phase 1a trial of ATI-052, an anti-TSLP/IL-4Rα bispecific antibody, showing a potential best-in-class pharmacokinetic profile with an estimated half-life of approximately 45 days, supporting up to three-month dosing. The trial demonstrated complete and sustained inhibition of TSLP-induced and IL-4 induced CCL17 (TARC) and a favorable safety profile. Additionally, the company selected lichen planus as the lead indication for its selective ITK/JAK3 inhibitor ATI-2138, with a Phase 2b basket study expected to begin in the second half of 2026. Enrollment is ongoing for Phase 1b trials of ATI-052 in asthma and atopic dermatitis, with top-line results expected in H2 2026.
Key Highlights
- ATI-052 Phase 1a trial showed an estimated half-life of approximately 45 days.
- ATI-052 demonstrated complete and sustained inhibition of TSLP-induced and IL-4 induced CCL17 (TARC) for at least 20 weeks and 12 weeks, respectively.
- The PK/PD profile of ATI-052 supports potential for up to three-month dosing intervals.
- ATI-052 was well tolerated with a favorable safety profile; no anti-drug antibodies observed.
- Lichen planus selected as lead indication for ATI-2138, with a potential market opportunity of $1.0B to $4.0B in the U.S.
- Phase 1b trials for ATI-052 in asthma and atopic dermatitis are ongoing, with top-line results expected in H2 2026.
- A Phase 2b program for ATI-052 (initially targeting asthma) and a Phase 2b basket study for ATI-2138 (in lichen planus) are planned for Q4 2026 and H2 2026, respectively.