Highlights

  • Aclaris reported a 45% placebo-adjusted mean improvement in EASI score at day 57 in its Phase 1b atopic dermatitis trial.
  • In the asthma trial, one 480 mg dose gave a 59% mean FeNO reduction at day 15, against 15% for placebo.
  • Preliminary, unaudited cash, cash equivalents and marketable securities were estimated at approximately $204.6 million as of September 30, 2026.
  • Aclaris intends to start a Phase 2b trial of ATI-052 in eosinophilic esophagitis in early 2027.

Aclaris Therapeutics (NASDAQ: ACRS) shares were trading at USD 3.75 on October 27, 2026, down 1.06%, with a relative volume at time of 4.55. The clinical-stage biopharmaceutical company announced primary analysis results from two Phase 1b proof-of-concept trials of its bispecific antibody ATI-052 on October 27, 2026, and gave a preliminary estimate of cash as of September 30, 2026.

Aclaris is incorporated in Delaware and lists its principal executive offices in Wayne, Pennsylvania. It describes itself as a clinical-stage biopharmaceutical company developing novel product candidates for patients with immuno-inflammatory diseases. ATI-052 is an investigational humanized anti-TSLP and anti-IL-4R alpha bispecific antibody, and the company holds exclusive worldwide rights to it, excluding Greater China. Its Annual Report on Form 10-K covers the year ended December 31, 2025.

Atopic Dermatitis Trial

The randomized, double-blind, placebo-controlled Phase 1b trial enrolled 14 patients with severe atopic dermatitis. Patients were randomized 3:1 to five weekly doses of 480 mg of ATI-052 or placebo, with primary analysis endpoints assessed at day 57. Four patients were excluded from the prespecified per-protocol analysis for reasons defined before unblinding, leaving nine patients in the ATI-052 arm and one patient in the placebo arm.

At day 57, the company reported a 45% placebo-adjusted mean improvement in Eczema Area and Severity Index (EASI) score from baseline, reflecting a 58% mean improvement in the ATI-052 arm and a 13% mean improvement in the placebo arm. It reported a 78% placebo-adjusted EASI-50. At week 10, the mean EASI improvement in the ATI-052 arm was 62%, and the company said it was maintained through week 16 for the subset of patients with available data.

On itch, measured by the Peak Pruritus Numerical Rating Scale, the company reported a 40% placebo-adjusted mean improvement at week 4 and a 43% placebo-adjusted mean improvement at day 57.

Asthma Trial

The Phase 1b asthma trial randomized 16 patients with mild-to-moderate asthma and baseline FeNO of at least 35 parts per billion, 3:1, to a single 480 mg dose of ATI-052 or placebo. The analysis population was 12 patients in the ATI-052 arm and four in the placebo arm, with endpoints assessed through day 29.

At day 15, patients on ATI-052 had a 59% mean reduction from baseline in FeNO, a mean absolute reduction of 45 parts per billion, compared with 15% in the placebo arm. At day 15, 58% of patients on ATI-052 reached FeNO of 25 parts per billion or less. FEV1 improved by 200 mL on a placebo-adjusted and absolute mean basis at day 15. In a post hoc subgroup with baseline FEV1 below 80% predicted and qualifying reversibility, the ATI-052 arm showed a 350 mL mean improvement from baseline, compared with a 140 mL mean decrease in the placebo arm.

Safety, Cash and Next Steps

Aclaris said ATI-052 was well tolerated across both trials. Treatment-emergent adverse events were predominantly Grade 1, with no Grade 3 or Grade 4 events, and no adverse events led to study discontinuation. Injection-site reactions were almost exclusively Grade 1, and no conjunctivitis was observed.

In the same filing, the company estimated that its cash, cash equivalents and marketable securities were approximately $204.6 million as of September 30, 2026, based on preliminary estimates. The amount has not been audited, reviewed or compiled by its independent registered public accounting firm, and the company said actual figures may differ and the differences may be material.

Aclaris said it intends to prioritize clinical development of ATI-052 initially in eosinophilic esophagitis and to initiate a Phase 2b trial in early 2027. It expects to provide an update on plans for a potential additional indication in the near term. The company noted risks that include uncertainties inherent in clinical trials and associated with preliminary data.