Q32 Bio Reports Positive Phase 2 Results for Bempikibart in Alopecia Areata

Q32 Bio Inc. has announced positive 36-week topline results from Part B of its SIGNAL-AA Phase 2a clinical trial (NCT06018428), evaluating bempikibart in patients with severe or very severe alopecia areata (AA). Bempikibart, also known as ADX-914, is a fully human anti-IL-7Rα antibody that works by blocking IL-7 and TSLP signaling to re-regulate adaptive immune function. The data were announced on July 13, 2026, alongside a company conference call featuring dermatology key opinion leader Arash Mostaghimi, MD, of Brigham and Women’s Hospital, Harvard Medical School.

Trial Design

Part B of SIGNAL-AA is a multicenter, open-label study that built on the earlier placebo-controlled Part A, which had established proof of concept for bempikibart in AA. The trial enrolled 33 patients with severe or very severe AA, defined by baseline SALT scores of 50 to 100, with a current disease episode lasting up to four years. Enrollment exceeded the study’s initial target because of strong patient demand. About 36.4% of participants had previously been treated with oral JAK inhibitors. Patients received an initial loading dose of 200 mg bempikibart subcutaneously once weekly for four doses, followed by 200 mg every other week through week 36. Off-drug follow-up continues through week 52, after which eligible patients may enter an open-label extension.

Efficacy Results

The trial met it’s prespecified primary endpoint, with a mean 35.3% reduction in SALT score from baseline at week 36 in the prespecified modified intent-to-treat (mITT) population. A SALT-20 response, corresponding to at least 80% scalp hair coverage, was achieved by 40.0% (10 of 25) of mITT patients and 30.3% (10 of 33) of all enrolled patients in the intent-to-treat (ITT) analysis. SALT30 and SALT50 responses were each reached by 44.0% of mITT patients and 33.3% of ITT patients. Early signals of durability were also observed after treatment discontinuation, with several patients maintaining or deepening their response, including one patient who achieved complete scalp hair regrowth (SALT score of 0).

Safety Profile

Bempikibart’s safety profile in Part B was consistent with earlier findings, and no new safety signals emerged. No treatment-related serious adverse events or Grade 3 or higher adverse events were reported. Injection site reactions were the most common adverse event, occurring in 36.3% of patients, corresponding to a 4% incidence across all dose administrations. These reactions were mild and largely resolved within a day without intervention. Pharmacokinetic and pharmacodynamic analyses showed the loading-dose regimen reached steady-state concentrations roughly 10 weeks earlier than in Part A, and anti-drug antibody formation was negligible.

Part A Open-Label Extension

Separately, Q32 Bio reported completed results from the open-label extension (OLE) of SIGNAL-AA Part A, which began in April 2025 following signs of durable response after treatment cessation. Eight patients from Part A, including responders, non-responders, and prior placebo recipients, re-entered dosing after off-drug intervals ranging from 26 to 55 weeks. Patients who had maintained hair growth at OLE entry showed durable or further improvement, and no new safety concerns were identified, supporting the case for a maintenance dosing approach.

Regulatory Path Forward

Based on the Part B results; Q32 Bio intends to advance bempikibart into a registration-directed development program in the first half of 2027. Full Part B data are expected to be presented at a future medical meeting.

What This Means for Patients

Alopecia areata affects roughly 700,000 people in the United States and can cause substantial hair loss that significantly affects quality of life. Although JAK inhibitors have expanded treatment options, they may not be suitable or effective for every patient. The Phase 2 findings suggest bempikibart could promote meaningful scalp hair regrowth with an encouraging tolerability profile, including in patients previously treated with JAK inhibitors. If confirmed in larger registration-directed studies, bempikibart may eventually provide clinicians and patients with a new subcutaneous treatment option, although its long-term efficacy and safety will need to be confirmed before it can be considered for regulatory approval.

Reference

Q32 Bio Announces Positive 36-Week Topline Results from Part B of the SIGNAL-AA Clinical Trial of Bempikibart in Alopecia Areata – Q32 Bio Inc.