First patient dosed as Bambusa expands global development of its long-acting bispecific antibody targeting both IL-4Rα and IL-31

High-concentration subcutaneous formulation designed to combine BBT001's emerging profile of rapid, deep and durable clinical activity with convenient administration and the potential for infrequent maintenance dosing

Milestone demonstrates continued execution of Bambusa's strategy to bring together efficacy, durability and dosing convenience in a single differentiated therapy for patients with chronic inflammatory skin disease

Bambusa Therapeutics, Inc. (Bambusa), a clinical-stage biotechnology company advancing next-generation, long-acting bispecific antibodies for immunology and inflammation (I&I),  announced that the first patient has been dosed in the subcutaneous (SC) cohort of its ongoing global Phase 1 clinical trial of BBT001 at a clinical research center in New Zealand. BBT001 is Bambusa's half-life-extended, bispecific antibody engineered to block IL-4Rα and IL-31 signaling, with the goal of addressing both Type 2 inflammation and itch in patients with atopic dermatitis (AD) and other Type 2 inflammatory skin diseases. The initiation of SC dosing follows the potentially transformative preliminary proof-of-concept results already achieved with intravenously administered BBT001 and expands Bambusa's evaluation of a potentially more convenient treatment approach for chronic use in AD patients.

"Subcutaneous dosing represents an important step in advancing BBT001 as a differentiated, long-acting and convenient therapy for patients with atopic dermatitis," said Thang Ho, Ph.D., Co-Founder and Chief Development Officer of Bambusa Therapeutics. "The prolonged half-life observed in healthy volunteers and patients, together with the compelling clinical activity demonstrated in our intravenous proof-of-concept study and our high-concentration subcutaneous formulation, provides a strong foundation for the late-stage development of BBT001. We are now focused on translating BBT001's rapid, deep and durable clinical profile into a convenient subcutaneous therapy with the potential for infrequent maintenance dosing. This study represents an important part of our advancement of the BBT001 development program, with preparations for our Phase 2b study already underway."

Compelling Clinical Proof of Concept Data

In July 2026, Bambusa reported preliminary results from a randomized, double-blind, placebo-controlled proof-of-concept cohort enrolling biologic-naïve patients with moderate-to-severe AD from New Zealand and the United States. After four weeks of treatment, BBT001 demonstrated rapid, deep and durable clinical activity:

• Rapid and deep skin responses: Statistically significant placebo-adjusted EASI improvement was observed beginning at Week 1 (35.6%; p=0.0012), deepening to 79.0% at Week 6 (p<0.0001), with a 64% placebo-adjusted EASI-75 response at Week 6. The placebo-adjusted EASI reduction deepened through Week 6 and remained sustained throughout the follow-up period.
• Rapid and progressively greater itch relief. BBT001 reduced PP-NRS scores as early as Day 1, with improvements deepening throughout treatment and remaining sustained for eight weeks after the last dose.
• Durable pharmacology: Type 2 inflammatory biomarkers, including TARC and IgE, were substantially suppressed, with effects sustained for eight weeks following the last dose.
• Favorable emerging profile: BBT001 was observed to be well tolerated, with no cases of conjunctivitis reported and low immunogenicity. An approximately 33-day half-life, together with sustained clinical and pharmacodynamic activity, support the potential for maintenance dosing as infrequently as once every three months.