Bempikibart Shows Positive Phase 2a Results in Alopecia Areata

Q32 Bio recently announced positive 36-week topline results from Part B of the SIGNAL-AA phase 2a trial evaluating bempikibart in patients with severe or very severe alopecia areata (AA). Bempikibart, a fully human anti-IL-7Rα antibody, reduced mean Severity of Alopecia Tool (SALT) score by 35.3% from baseline in the modified intent-to-treat (mITT) analysis at week 36. The company reported a generally well-tolerated safety profile, with no new safety signals observed.¹

The Part B results build on proof-of-concept data from SIGNAL-AA Part A (NCT06018428) and include patients with prior exposure to oral Janus kinase (JAK) inhibitors. Among the 33 enrolled patients, 36.4% (12/33) had previously received JAK inhibitor therapy, positioning bempikibart as a potential option for patients without durable control on existing agents. Q32 Bio said the data support advancing bempikibart into a registration-directed program in the first half of 2027.¹

SIGNAL-AA Part B is an open-label trial evaluating bempikibart in 33 patients with severe or very severe AA, defined as baseline SALT scores of 50 to 100, with a maximum current episode duration of four years. Patients received an initial loading regimen of bempikibart 200 mg administered subcutaneously (SC) weekly for four doses, followed by 200 mg SC every other week through week 36. Total enrollment exceeded the initial target due to patient demand.¹

The prespecified primary efficacy analysis assessed mean percentage change from baseline in SALT score in the mITT population. At week 36, bempikibart produced a mean SALT score reduction of 35.3% from baseline in the mITT analysis. A SALT-20 response, defined as 80% scalp hair coverage, was achieved by 40.0% (10/25) of patients in the mITT analysis and 30.3% (10/33) of patients in the intent-to-treat (ITT) analysis, with responses observed across both severe and very severe disease.¹

Arash Mostaghimi, MD, MPA, MPH, associate professor of dermatology and vice chair of clinical trials and innovation at Brigham and Women's Hospital, Harvard Medical School, said the Part B findings reinforce bempikibart's potential as an alternative to JAK inhibitors.

"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," Mostaghimi said. "For patients and prescribers seeking an effective and safe alternative to JAK inhibitors, these findings are encouraging and merit further clinical advancement."¹

Bempikibart Secondary End Points and Safety

Bempikibart produced additional improvement on secondary SALT end points at week 36. SALT30, a 30% improvement in SALT score from baseline, was achieved by 44.0% (11/25) of patients in the mITT analysis and 33.3% (11/33) of patients in the ITT analysis. SALT50, a 50% improvement from baseline, was achieved by the same proportions: 44.0% (11/25) in the mITT analysis and 33.3% (11/33) in the ITT analysis.¹

Q32 Bio reported bempikibart demonstrated a generally well-tolerated safety profile in Part B, consistent with prior studies, with no new safety signals observed. No serious adverse events or grade 3 or higher treatment-related adverse events occurred. The most common treatment-emergent adverse event was injection site reaction, occurring in 36.3% of patients, with an incidence of 4% across all Part B dose administrations.¹

Injection site reactions were largely singular events, described as mild and resolved without intervention, with most resolving within one day. Bempikibart also demonstrated a favorable pharmacokinetic, pharmacodynamic, and anti-drug antibody profile in Part B. The loading dose regimen achieved steady-state concentrations approximately 10 weeks earlier than in Part A, with negligible anti-drug antibody observed.¹

"These results provide important further evidence that our differentiated approach to targeting the biology underlying alopecia areata has the potential to translate into meaningful and durable clinical benefit for patients," said Shelia Violette, PhD, co-founder and chief scientific officer of Q32 Bio, in the news release. "Despite recent advances, many patients continue to seek treatment options that combine robust efficacy with improved safety and the potential for sustained disease control. These findings strengthen our confidence in the therapeutic potential of this mechanism and its continued advancement as a differentiated treatment option for patients living with alopecia areata and other autoimmune and inflammatory diseases."¹

Q32 Bio said the completed Part A open-label extension, in which 8 patients previously off drug for 26 to 55 weeks resumed dosing, supports the importance of a maintenance regimen for durable hair regrowth. The company plans to share full Part B data at a future medical meeting as it advances bempikibart toward registration-directed development.¹

Clinical Need

The FDA granted Fast Track Designation to bempikibart in March 2025 for severe alopecia. Jodie Morrison, chief executive officer of Q32 Bio, described the designation as an opportunity to address the seriousness of AA and the unmet need.²

"The Fast Track designation granted by the FDA recognizes the seriousness of AA and the significant current unmet medical need while underscoring bempikibart's potential as a novel, differentiated therapy for patients needing new options. This Fast Track designation follows the encouraging clinical activity observed in Part A of our SIGNAL-AA clinical trial and the recent initiation of dosing in the Part A open-label extension and Part B portions of the SIGNAL-AA trial. We look forward to continued collaboration with the FDA as we work to deliver this potentially paradigm-shifting treatment to patients."²

References

1. Q32 Bio announces positive 36-week topline results from part B of the SIGNAL-AA phase 2a clinical trial of bempikibart in alopecia areata. Q32 Bio Inc. July 13, 2026. Accessed July 13, 2026. https://ir.q32bio.com/news-releases/news-release-details/q32-bio-announces-positive-36-week-topline-results-part-b-signal
2. Q32 Bio announces FDA fast track designation granted to bempikibart (ADX-914) for the treatment of alopecia areata. Q32 Bio. April 30, 2025. Accessed April 30, 2025. https://ir.q32bio.com/news-releases/news-release-details/q32-bio-announces-fda-fast-track-designation-granted-bempikibart/

Frequently Asked Questions

What is bempikibart being studied for in alopecia areata?
Bempikibart is a fully human anti-IL-7Rα antibody in Phase 2a development for severe or very severe alopecia areata, including patients with prior JAK inhibitor exposure.

How does bempikibart work in alopecia areata?
Bempikibart blocks IL-7 and thymic stromal lymphopoietin (TSLP) signaling through the IL-7Rα receptor, re-regulating adaptive immune function implicated in AA.

What did the SIGNAL-AA Part B trial show?
At week 36, bempikibart reduced mean SALT score by 35.3% from baseline in the mITT analysis, with 40.0% (10/25) of mITT patients achieving a SALT-20 response.