Phase 1 results show Bambusa Therapeutics’ BBT001 quickly reduces atopic dermatitis and itch, sustains type 2 biomarker suppression, and may enable quarterly dosing.
Preliminary data from
"I had the opportunity to enroll several patients with severe AD in this study and saw firsthand the substantial burden this disease placed on their lives," said
BBT001 is a half-life-extended bispecific antibody designed to target both interleukin-4 receptor alpha (IL-4Rα) and interleukin-31 (IL-31). The proof-of-concept AD cohort is part of an ongoing global, randomized, double-blind, placebo-controlled phase 1 trial (
The study enrolled biologic-naïve adults with moderate to severe AD who had not previously received biologics targeting the same pathways as BBT001 or Janus kinase inhibitors. Participants were randomized 2:1 to receive either 450 mg IV BBT001 or placebo every 2 weeks during a 4-week treatment period at sites in the US and New Zealand. Primary endpoints included safety and tolerability, while exploratory endpoints assessed changes in Eczema Area and Severity Index (EASI), Peak Pruritus Numerical Rating Scale (PP-NRS) scores, and type 2 inflammatory biomarkers. At the June 8, 2026 data cutoff, 17 patients had been enrolled, including 12 treated with BBT001 and 5 receiving placebo. Median follow-up was 71 days after the first dose.
Key Preliminary Findings from Phase 1 Study of BBT001
Treatment with BBT001 was associated with statistically significant improvements in EASI beginning at week 1. Placebo-adjusted EASI reductions were 35.56% at week 1 (P = .0012), 61.10% at week 2, 63.46% at week 4, and 78.95% at week 6 (all P < .0001). As the company noted, improvements continued through week 12 and remained sustained in patients with longer follow-up.
Exploratory efficacy analyses also favored BBT001. Placebo-adjusted EASI-50 response rates increased from 25% at week 1 to 75% at week 2 and 91% at week 4 before reaching 82% at week 6. Placebo-adjusted EASI-75 responses increased from 17% at week 2 to 45% at week 4 and 64% at week 6. Pruritus improved rapidly following treatment initiation. Reductions in PP-NRS scores were observed as early as day 1 after the first dose, with placebo-adjusted improvements of 29% at week 1, 35% at week 2, 41% at week 4, and 43% at week 6. Investigators reported that itch relief remained evident for up to 8 weeks after the final dose.
Biomarker analyses demonstrated early reductions in thymus and activation-regulated chemokine (TARC) and immunoglobulin E (IgE), with suppression maintained for 8 weeks after treatment, indicating continued inhibition of type 2 inflammatory activity after dosing concluded. Preliminary safety findings were also favorable. BBT001 was reported to be well tolerated, and no cases of conjunctivitis were observed during the study. Investigators also reported a low incidence of treatment-emergent anti-drug antibodies, with low titers and no apparent neutralizing activity. Pharmacokinetic findings demonstrated an extended half-life consistent with prior healthy volunteer data, supporting the evaluation of maintenance dosing intervals as long as once every 3 months in future studies.
Bambusa Therapeutics plans to present the complete dataset at an upcoming medical meeting and intends to initiate a phase 2b trial evaluating extended maintenance dosing in moderate-to-severe AD. Additional topline results are expected in the first half of 2027 from ongoing studies evaluating both IV and subcutaneous formulations of BBT001 in biologic-naïve and biologic-experienced patients with AD, as well as in patients with chronic spontaneous urticaria.
"Despite important advances in AD treatment, patients and physicians are still looking for therapies that provide more complete control of both skin lesions and itch without the burden of frequent dosing," Eric Simpson, MD, MCR, professor of dermatology and director of clinical research at Oregon Health & Science University and a member of Bambusa's Scientific Advisory Board, said in the press release. "The rapid onset and depth of response observed with BBT001 in this study, together with its favorable safety results and potential for extended dosing intervals, make BBT001's emerging profile particularly compelling. If these findings are confirmed in larger and longer studies and if BBT001 is approved, it could meaningfully raise the standard of care for patients with moderate to severe AD."1
References
1. Bambusa Therapeutics Reports Potentially Transformative Preliminary Proof-of-Concept Results for BBT001 in Atopic Dermatitis, Reinforcing Its Best-in-Disease Potential. News release. PR Newswire. Published July 27, 2026. Accessed July 28, 2026.
2. Bambusa Therapeutics announces highly positive healthy volunteer results and first atopic dermatitis patient dosed in phase I trial of BBT001. News release. Bambusa Therapeutics. Published September 25, 2025. Accessed July 28, 2026.
