Bempikibart Maintains Responses After Treatment Discontinuation in Alopecia Areata

Q32 Bio reported additional results from Part B of the SIGNAL-AA Phase 2a (NCT06018428) clinical trial evaluating bempikibart in patients with severe or very severe alopecia areata (AA). The findings were presented as a late-breaking oral presentation and poster at the European Academy of Dermatology and Venereology (EADV) Congress 2026 in Vienna, Austria.

Q32 Bio previously reported the 36-week topline results from SIGNAL-AA Part B in July 2026. The current EADV update provides an extended analysis of responses during the 16-week period following treatment discontinuation.

The data showed continued scalp hair growth through 36 weeks of treatment, with responses maintained during the initial 16-week off-treatment period among patients who had demonstrated hair growth during treatment.

Bempikibart and Its Mechanism

Bempikibart is a fully human monoclonal antibody targeting interleukin-7 receptor alpha (IL-7Rα), blocking signaling from both IL-7 and thymic stromal lymphopoietin (TSLP). Q32 Bio is developing bempikibart as an immune-modulating AA treatment operating via a mechanism distinct from JAK inhibition.

SIGNAL-AA Part B Study Design

SIGNAL-AA Part B is an open-label Phase 2a study enrolling 33 patients with baseline Severity of Alopecia Tool (SALT) scores ranging from 50 to 100.

Patients received subcutaneous bempikibart 200 mg weekly for four loading doses, followed by 200 mg every two weeks through Week 36, then entered a 16-week treatment-free follow-up period. Eligible participants could subsequently join an open-label extension.

The prespecified primary efficacy endpoint assessed mean percentage change from baseline in SALT score in the modified intent-to-treat (mITT) population (n=25).

Week 36 Efficacy Results At Week 36, mean reduction in SALT score from baseline was 35.3% in the mITT population.

• SALT-20 (<=20 absolute score): Achieved by 40.0% (10/25) of mITT patients and 30.3% (10/33) of intent-to-treat (ITT) patients.

• SALT30 (>=30% improvement): Achieved by 44.0% (11/25) of mITT patients and 33.3% (11/33) of ITT patients.

• SALT50 (>=50% improvement): Achieved by 44.0% (11/25) of mITT patients and 33.3% (11/33) of ITT patients.

Responses in Patients with Prior JAK Inhibitor Exposure In an exploratory analysis of 10 mITT patients with prior oral JAK inhibitor exposure:

• Prior JAK Responders (n = 4): Achieved a 48.3% mean SALT score reduction.

• Prior JAK Non-Responders (n = 6): Achieved a 4.8% mean SALT score reduction.

• JAK-Naïve Patients: Achieved a 44.1% mean SALT score reduction.

These small subgroup analyses are descriptive and exploratory and do not establish differential efficacy based on prior JAK response.

Responses After Treatment Discontinuation

Eighteen patients entered the 16-week off-drug follow-up period. At the end of follow-up, response rates in this cohort (n=18) were 44% (8/18) for SALT-20, 61% (11/18) for SALT30, and 50% (9/18) for SALT50.

Of these 18 patients, 12 had demonstrated hair growth by Week 36. Defining response maintenance as a -point worsening in SALT score from the final on-treatment value, all 12 patients () maintained response off-drug, with 5 experiencing further improvement.

Individual trajectories included one patient improving from SALT-10 at Week 36 to complete regrowth (SALT 0), two improving from SALT-20 to SALT-10, and one latent responder reaching SALT-20 during follow-up. Because this off-drug analysis involved a subset (n=18), findings should not be directly compared with Week 36 mITT rates.

Pharmacodynamic and Biomarker Findings

Pharmacodynamic evaluation demonstrated reductions in CD3+ T cells and changes in T-effector cytokines. Patients with higher baseline biomarkers showed reductions in IFN$\gamma$, IL-17, IL-6, TARC, IgE, and eosinophils, as well as decreases in downstream CXCL10. Post-treatment biopsies revealed reduced perifollicular CD3+/CD8+ infiltrates and increased anagen follicles. These exploratory analyses support bempikibart’s biological activity.

Safety and Development

Bempikibart was generally well tolerated with no new safety signals, treatment-related SAEs, or Grade  adverse events. Mild injection-site reactions occurred in 36.3% (12/33) of patients (4% per-injection incidence).

Q32 Bio is utilizing the open-label extension to evaluate monthly, Q2M, and quarterly maintenance dosing, targeting a registration-directed program entry in severe or very severe AA in H1 2027, subject to regulatory discussions.

Preliminary Evidence of Treatment-Free Response

These findings provide preliminary evidence of clinical activity and sustained off-treatment hair growth. However, given the small, open-label, uncontrolled study design, these exploratory analyses do not establish long-term durability or definitive clinical benefit, necessitating larger controlled trials.

Reference

Q32 Bio Presents Results from Part B of the SIGNAL-AA Clinical Trial of Bempikibart in Alopecia Areata in a Late-Breaker at the European Academy of Dermatology and Venereology Congress 2026, Q32 Bio, 30 September 2026

A Phase 2a Proof-of-Concept Trial of Bempikibart (ADX-914) for the Treatment of Severe Alopecia Areata (SIGNAL-AA) (SIGNAL-AA), ClinicalTrials.gov ID NCT06018428