Q32 Bio Inc. (Nasdaq: QTTB) announced results from Part B of the SIGNAL-AA Phase 2a clinical trial evaluating bempikibart in patients with severe or very severe alopecia areata. The data, presented at the European Academy of Dermatology and Venereology Congress 2026, includes 36-week treatment results and initial findings from a 16-week off-drug follow-up period.
The trial enrolled 33 patients with baseline Severity of Alopecia Tool (SALT) scores of 50-100. Bempikibart is a fully human anti-IL-7Rα antibody. Patients received a 200mg loading dose weekly for four weeks, followed by 200mg every other week for 32 weeks.
At Week 36, the mean percent reduction in SALT score from baseline was 35.3% in the modified intent-to-treat population. Key response rates included 40.0% (10/25) achieving SALT-20 (80% scalp coverage) and 44.0% (11/25) achieving SALT-50 (50% improvement) in the mITT analysis. Among patients with prior oral JAK inhibitor exposure, those who had responded to prior therapy saw a mean SALT reduction of 48.3%, compared to 4.8% in non-responders.
During the 16-week off-drug follow-up period, 18 patients were evaluated. Response rates at this time point were 44% for SALT-20, 61% for SALT-30, and 50% for SALT-50. The company reported that maintenance of response was observed in 100% of patients who had demonstrated hair growth by Week 36, with deepening of response observed in 42% of these patients.
Regarding safety, the company reported no serious adverse events or Grade 3 or higher adverse events related to treatment. The most common treatment-emergent adverse event was injection site reaction (ISR), occurring in 36.3% of patients. All ISRs were mild and resolved without intervention.
Q32 Bio stated that these results support advancing bempikibart into a registration-directed program for severe or very severe alopecia areata in the first half of 2027. The company also noted that eligible patients can enroll in an open-label extension (OLE) and anticipates OLE data in the second half of 2027.
