Q32 Bio Inc. (Nasdaq: QTTB) reported 36-week topline results from Part B of its SIGNAL-AA Phase 2a clinical trial evaluating bempikibart, an anti-IL-7Rα antibody, in patients with severe or very severe alopecia areata.

The trial enrolled 33 patients with baseline Severity of Alopecia Tool (SALT) scores of 50 to 100 and a maximum duration of current episode of four years. Of those enrolled, 36.4% had prior exposure to oral JAK inhibitor therapy. Patients received 200mg of bempikibart weekly for four doses, followed by 200mg every other week for 32 weeks, administered subcutaneously.

In the prespecified modified intent-to-treat (mITT) analysis, the mean percent reduction in SALT score from baseline was 35.3% at Week 36. In the same population, 40.0% of patients achieved a SALT-20 response, defined as 80% scalp hair coverage. In the broader intent-to-treat (ITT) analysis of all 33 enrolled patients, 30.3% achieved SALT-20 response. Additionally, 44.0% of mITT patients achieved both SALT-30 and SALT-50 responses.

No serious adverse events or Grade 3 or higher treatment-related adverse events were reported. The most common treatment-emergent adverse event was injection site reaction, occurring in 36.3% of patients, though incidence across all dose administrations was 4%. All injection site reactions were mild and resolved without intervention.

Early off-drug follow-up data showed maintenance or deepening of response in multiple patients, including one who achieved complete hair growth. The off-drug follow-up period through Week 52 remains ongoing.

Q32 Bio stated it intends to advance bempikibart into a registration-directed program in the first half of 2027. Full results from Part B are planned for presentation at a future medical meeting.

Separately, the company reported completion of the Part A open-label extension, in which eight patients re-enrolled after off-drug periods ranging from 26 to 55 weeks. Patients who maintained hair at entry showed durable or further hair growth, with no new safety signals observed.