Q32 Bio’s Bempikibart Shows Durable Hair Regrowth in Phase 2 Alopecia Study

Key Points

• Q32 Bio reported positive 36-week Phase 2a results for bempikibart in severe and very severe alopecia areata, including a 35.3% mean SALT score reduction in the primary mITT analysis and 40% of patients reaching the SALT-20 endpoint.
• The drug appeared to show a durable hair regrowth response with no evidence of plateau, while also being well-tolerated: there were no Grade 3+ adverse events, no new safety signals, and only mild injection-site reactions.
• The company plans to use the data to support Phase 3 discussions with regulators, with a registration-directed program targeted for the first half of 2027 and potential maintenance dosing still being evaluated through follow-up data.

Q32 Bio NASDAQ: QTTB reported positive 36-week top-line results from Part B of its SIGNAL-AA Phase 2a clinical trial evaluating bempikibart in patients with severe and very severe alopecia areata, a disease that causes hair loss and can carry a significant psychosocial burden.

President and Chief Financial Officer Lee Kalowski opened the call by saying the company would review the results, the unmet need in alopecia areata and the potential commercial opportunity. Chief Executive Officer Jodie Morrison said the findings marked “a significant milestone” for the company’s bempikibart development program and for patients.

“We believe the efficacy, durability, and safety results from Part B have the potential to set the bar for biologics in the treatment of alopecia areata and address the shortcomings of JAK inhibitors,” Morrison said.

Trial Met Key Efficacy Measures

In the pre-specified modified intent-to-treat, or mITT, primary analysis, Q32 Bio said bempikibart produced a 35.3% mean reduction from baseline in score on the Severity of Alopecia Tool, or SALT, over the 36-week treatment period. Morrison said 40% of patients in the mITT population achieved the SALT-20 endpoint, which she described as the currently accepted registration endpoint. In the full intent-to-treat population, 30.3% of patients achieved SALT-20.

The company said the study enrolled patients with severe and very severe alopecia areata, defined by baseline SALT scores of 50 to 100. In the mITT population, the mean age was 42, 76% of participants were female, and the average baseline SALT score was 76.9. Approximately 76% of patients were classified as severe and 24% as very severe. Forty percent had prior oral JAK inhibitor exposure.

Q32 Bio reported a 37.8% mean SALT reduction at week 36 in the severe subgroup and a 27.4% reduction in the very severe subgroup. Morrison said the results showed “clear and sustained hair regrowth” with responses deepening over time and “no evidence of plateau.”

Bempikibart Mechanism and Dosing

Shelia Violette, Q32 Bio’s co-founder, chief scientific officer and president of research, described bempikibart as a fully human antibody that binds to the IL-7 receptor alpha subunit, blocking signaling from IL-7 and TSLP. She said the mechanism is designed to remodulate immune activity across T cell-mediated autoimmune and inflammatory diseases.

Part B of SIGNAL-AA used a loading regimen of 200 mg weekly for four weeks, followed by 200 mg every other week for 32 weeks. Bempikibart is administered subcutaneously. Morrison said the company expects this dosing regimen to be the one it takes into Phase 3 development, though she said Q32 Bio is not yet able to separate the contribution of the loading regimen from the longer 36-week treatment period.

The company said the loading regimen achieved its intended pharmacokinetic effect. Mean trough levels were approximately threefold higher in the first month compared with Part A of SIGNAL-AA, and steady-state concentrations were reached about 10 weeks earlier than in Part A and sustained through week 36.

Safety Profile and Durability

Q32 Bio said bempikibart was well-tolerated in Part B, with no Grade 3 or higher adverse events, no new safety signals and no discontinuations related to safety findings. The most common treatment-emergent adverse event was injection site reaction, occurring in approximately 36% of patients. The company said most of these were single events, producing an incidence of 4% across all Part B dose administrations. All injection site reactions were mild and resolved without intervention.

Morrison said patients are continuing through a 16-week off-drug follow-up period through week 52, and the company is enrolling eligible patients in an open-label extension. She said Q32 Bio will use the off-drug follow-up data to help define a potential chronic maintenance regimen, including options such as monthly, bimonthly or quarterly dosing.

The company also presented case examples of patients who maintained or deepened responses after stopping treatment, including one patient who achieved SALT 0 at week 44 after completing the treatment period. Q32 Bio said it plans to share full Part B results at a future medical meeting.

Market Context and Next Steps

Kalowski said alopecia areata affects approximately 700,000 people in the U.S. and that the disease has few approved options for severe and very severe patients. He noted that JAK inhibitors are currently the only approved advanced therapies in the disease, while no biologic therapy is approved for alopecia areata.

Kalowski said Q32 Bio partnered with IQVIA on a survey of 50 dermatologists, which identified improved safety, lack of black box warnings, minimal lab monitoring and better durability of effect as key unmet needs. He said U.S. net sales of oral JAK inhibitors in alopecia areata are expected to reach approximately $500 million in 2026. Based on Q32 Bio’s work with IQVIA, the company forecast a total U.S. market opportunity of at least $5 billion in 2037.

Morrison said Q32 Bio plans to hold regulatory discussions and intends to initiate a registration-directed program in severe and very severe alopecia areata in the first half of 2027. During the question-and-answer session, she said the company expects to have an end-of-Phase 2 meeting by the end of the year and intends to discuss Phase 3 design with regulators.

Dr. Arash Mostaghimi, associate professor of dermatology at Harvard Medical School and vice chair of clinical trials and innovation at Brigham and Women’s Hospital, said the data suggest bempikibart could provide “JAK-like efficacy” with a safety profile familiar to dermatologists who prescribe biologic therapies. He said, if validated in Phase 3, the profile could address concerns that limit the use of JAK inhibitors, including black box warnings and monitoring requirements.

“If these results bear out the way we’re hoping in a Phase III trial, this should be the first-line treatment for patients with alopecia areata,” Mostaghimi said.

About Q32 Bio NASDAQ: QTTB

Q32 Bio Inc, a clinical-stage biotechnology company, develops biologic therapeutics to restore healthy immune balance in patients with autoimmune and inflammatory diseases driven by pathological immune dysfunction in the United States. Its lead product candidate is ADX-097, a humanized anti-C3d monoclonal antibody fusion protein to restore complement regulation, which has completed Phase I clinical trial for the treatment of renal and other complement-mediated diseases of high unmet need, including lupus nephritis, immunoglobulin A nephropathy, complement component 3 glomerulopathy, and anti-neutrophil cytoplasmic antibody-associated vasculitis.

This instant news alert was generated by narrative science technology and financial data from MarketBeat in order to provide readers with the fastest reporting and unbiased coverage. Please send any questions or comments about this story to contact@marketbeat.com.