Q32 Bio has reported positive 36-week Phase 2 data showing clinically meaningful hair regrowth in patients with severe alopecia areata treated with bempikibart.

Q32 Bio has reported positive topline results from the Phase 2a SIGNAL-AA clinical trial showing that its investigational therapy, bempikibart, achieved clinically meaningful hair regrowth in patients with severe or very severe alopecia areata.

The 36-week results showed the treatment met its primary endpoint, with patients experiencing a mean 35.3% reduction in Severity of Alopecia Tool (SALT) scores in the prespecified modified intent-to-treat analysis. The SALT score is a standard measure of scalp hair loss, with lower scores indicating greater hair coverage.

The open-label study enrolled 33 patients with severe or very severe alopecia areata, including individuals who had previously received oral JAK inhibitor treatment. Alopecia areata is an autoimmune condition in which the immune system attacks hair follicles, causing patchy or extensive hair loss.

By Week 36, 40% of patients in the modified intent-to-treat analysis achieved a SALT-20 response, equivalent to at least 80% scalp hair coverage. In the intent-to-treat analysis of all enrolled patients, 30.3% achieved the same level of response.

Researchers also reported that 44% of patients in the modified intent-to-treat population achieved both SALT30 and SALT50 responses, representing at least 30% and 50% improvements in hair regrowth respectively.

Importantly, early follow-up data suggested that several patients maintained or continued to improve their response after treatment had stopped, including one participant who achieved complete scalp hair regrowth.

Jodie Morrison, chief executive officer of Q32 Bio, said: “Today’s Part B 36-week topline results mark a significant milestone for Q32 Bio, supporting our target efficacy and safety profile and providing compelling evidence reinforcing the therapeutic potential of bempikibart in alopecia areata. We believe these findings highlight the opportunity to deliver a differentiated, targeted treatment option for patients who remain in need of an effective, safe, and more durable alternative to JAK inhibitors.”

Bempikibart is a fully human antibody designed to regulate immune activity by blocking IL-7 and thymic stromal lymphopoietin (TSLP) signalling, two pathways believed to play a role in autoimmune diseases including alopecia areata.

The treatment continued to demonstrate a favourable safety profile, consistent with previous studies. No new safety signals were identified, no serious treatment-related adverse events were reported and all injection site reactions were mild and resolved without intervention.

The study also demonstrated favourable pharmacokinetic, pharmacodynamic and anti-drug antibody profiles, supporting the selected dosing regimen and continued clinical development.

Arash Mostaghimi, associate professor of dermatology and vice chair of clinical trials and innovation at Brigham and Women’s Hospital, Harvard Medical School, said: “Alopecia areata is a complex, immune driven disease with limited therapeutic options. The robust efficacy data in a population that includes JAK inhibitor-experienced patients, combined with a differentiated safety profile, demonstrate the potential for bempikibart to be a first-line treatment for alopecia areata. For patients and prescribers seeking an effective and safe alternative to JAK inhibitors, these findings are encouraging and merit further clinical advancement.”

Q32 Bio said the off-treatment follow-up period will continue through Week 52, while eligible participants are also being enrolled into an ongoing open-label extension study. The company plans to begin a registration-directed clinical programme during the first half of 2027.