Aclaris Therapeutics — October 27, 2026 Earnings Summary

Financial Performance:

• No financial performance metrics (revenue, earnings, cash flow, debt, or margins) are disclosed in this press release, as the company is a clinical-stage biopharmaceutical firm reporting on Phase 1b trial results rather than financial results.

Guidance and Future Outlook:

• Aclaris intends to prioritize Phase 2b development of ATI-052 initially in Eosinophilic Esophagitis (EoE), aligning with its strategy for disciplined capital management.
• The company plans to initiate a Phase 2b trial in EoE early next year.
• An update on plans for a potential additional indication is expected in the near term.

Business Segments and Product Lines:

• ATI-052 (Anti-TSLP/IL-4Rα Bispecific Antibody):
  • Atopic Dermatitis (AD) Phase 1b Trial:
    • Evaluated 14 patients with severe AD receiving five weekly doses of 480 mg.
    • EASI Score: Patients experienced a 45% placebo-adjusted mean change in EASI score from baseline at day 57 (58% absolute change in active arm vs. 13% in placebo).
    • EASI-50: 78% placebo-adjusted EASI-50 achieved at day 57; 100% of patients with baseline vIGA 3 achieved this compared to 71% of patients with baseline vIGA 4.
    • Itch (PP-NRS): 40% placebo-adjusted mean improvement at week 4; 43% placebo-adjusted mean improvement at day 57 (38% absolute improvement vs. 5% worsening in placebo).
    • Response Rate: 33% of patients experienced a placebo-adjusted mean improvement of ≥4 points in itch at day 57.
    • Durability: Responses were durable for the subset of patients with data at week 16.
    • Pharmacodynamics: 95% normalization in the lesional skin proteome observed at week 8; broad downregulation of Th1, Th2, Th17/Th22, fibrosis, and itch-associated pathways; pronounced reduction of dupilumab biomarkers.
  • Asthma Phase 1b Trial:
    • Evaluated 16 patients with mild-to-moderate asthma receiving a single 480 mg dose.
    • FeNO: 59% mean absolute reduction in FeNO at day 15 (45 ppb) compared to 15% in placebo; 40% reduction at day 29.
    • FeNO Normalization: 58% of patients achieved FeNO normalization (≤25 ppb) at day 15.
    • FEV1: Placebo-adjusted and absolute mean improvement of 200 ml at day 15.
    • Subgroup Analysis: Patients with baseline FEV1 <80% and reversibility showed an absolute mean improvement of 350 ml at day 15 vs. a -140 ml worsening in placebo.
  • Safety: Well-tolerated across both trials; treatment-emergent adverse events were predominantly Grade 1 with no Grade 3 or 4 events or study discontinuations. Injection site reactions were transient and low frequency. No observations of conjunctivitis.
• Bosakitug (ATI-045): ATI-052 utilizes the same TSLP antigen-binding fragment as bosakitug, retaining its long residence time and high potency.
• Development Strategy: Aclaris has exclusive worldwide rights to ATI-052, excluding Greater China.

Market and Competitive Landscape:

• ATI-052 demonstrates potential best-in-class activity by simultaneously targeting TSLP, IL-4, and IL-13.
• ATI-052 exhibits slow dissociation kinetics from TSLP with a residence time up to 116x longer than comparator antibodies.
• The drug is engineered to bind more tightly to the neonatal Fc receptor (FcRn) to extend its half-life compared to comparators.
• Investigators noted that lung function improvements were "at least as good if not improving on those seen by comparator compounds."

Risks and Challenges:

• Clinical trial results are preliminary, interim, or topline data, which carry inherent uncertainties.
• Risks include the potential for actual results to differ materially from forward-looking statements due to uncertainties in trial conduct, reliance on third parties, and the ability to secure strategic partnerships.
• Macroeconomic environment risks are noted.
• Detailed risk factors are referenced in the company's Annual Report on Form 10-K for the year ended December 31, 2025.

Management Commentary and Tone:

• Dr. Neal Walker (CEO): Described results as conveying "the art of the possible," citing breadth and depth of response, normalization of the immune proteome, and a favorable safety profile. Expressed confidence in the compound's potential best-in-class activity.
• Dr. Michael Cameron (Investigator): Called the AD data "very noteworthy" for strength, rapidity, and durability, noting a refractory patient had a durable response lasting months beyond the last dose.
• Dr. Chris Brightling (Investigator): Stated results were "significantly better than encouraging," highlighting rapid improvements in FeNO and FEV1.
• Dr. Emma Guttman (Investigator): Confirmed pharmacodynamic biomarker results were clear and significantly correlated to efficacy, suggesting early potent anti-inflammatory activity.

Other Key Points:

• Aclaris will host a webcast and conference call at 8:00 AM ET on the announcement date to discuss results.
• Presentation slides are available for download at the time of the call.
• The company is a clinical-stage biopharmaceutical focused on immuno-inflammatory diseases with a multi-stage portfolio.
• Forward-looking statements include expectations regarding the initiation of the Phase 2b EoE trial and the potential for ATI-052 to treat atopic, immunologic, and respiratory diseases.