Aclaris Therapeutics Achieves Best-in-Class PK/PD Profile for Bispecific Antibody ATI-052 in Phase 1a Trial

A 45-day estimated half-life and complete target engagement through at least week 20 position ATI-052 as a candidate for quarterly dosing intervals, a profile that carries direct implications for biologics fill-finish scheduling and cold-chain planning at contract and captive manufacturing sites. Aclaris Therapeutics released full top-line results from its Phase 1a single and multiple ascending dose trial of the bispecific anti-TSLP/IL-4Rα antibody on 7 May 2026, confirming the compound exceeded the company's internal target profile.

In the 480 mg MAD cohort, pharmacodynamic data showed robust and sustained inhibition of ex vivo TSLP-stimulated CCL17 (TARC) through at least week 20, and ex vivo IL-4-stimulated CCL17 through at least week 12. The combination of PK duration and PD depth supports dosing intervals of up to every three months. ATI-052 was reported as well tolerated with a favorable safety profile across the trial population.

For biologics manufacturers and fill-finish planners, a quarterly dosing schedule compresses annual batch demand relative to monthly regimens, shifting the manufacturing planning horizon and potentially affecting campaign frequency, vial configuration, and stability study design under ICH Q1 shelf-life requirements. Early engagement with these variables is warranted given Aclaris's stated intent to initiate a Phase 2b program in asthma in Q4 2026.

Two Phase 1b proof-of-concept trials are currently dosing, one in atopic dermatitis, initiated January 2026, and one in asthma, initiated February 2026, with top-line results expected in the second half of 2026. Enrollment is also complete in a randomized, double-blind, placebo-controlled Phase 2 trial of bosakitug, an anti-TSLP monoclonal antibody, in 109 patients with atopic dermatitis; top-line data are expected in Q4 2026.

Separately, Aclaris announced a phased Phase 2b basket study strategy for ATI-2138, a selective ITK and JAK3 inhibitor, targeting the three most common subtypes of lichen planus, erosive mucosal, cutaneous, and a third subtype. The dual ITK/JAK3 mechanism is cited as the scientific rationale for the basket design, which addresses an indication with no currently approved therapies.

Aclaris reported a cash runway expected to sustain pipeline development through 2028, providing a defined operational window for CMC teams and external manufacturing partners to align process development timelines with the Phase 2b initiation target.

The Phase 1b top-line readouts in the second half of 2026 will be the next measurable checkpoint for assessing whether ATI-052's extended dosing profile holds in a patient population, directly informing the scale and configuration of Phase 2b manufacturing requirements.

Source: Aclaris Therapeutics, Inc. via GlobeNewswire, 7 May 2026.