CAMBRIDGE, Mass. — Zai Lab Limited announced that it has dosed the first participant in a global Phase 1/1b clinical study of ZL-1503, a potential first-in-class bispecific antibody designed to treat moderate to severe atopic dermatitis and other conditions driven by Type 2 helper T-cell (Th2) pathways. The therapy, discovered and developed internally, targets both IL-13 and IL-31 signaling with an extended serum half-life, aiming to deliver faster onset and improved efficacy.
Preclinical findings, recently presented at the 2025 European Academy of Allergy and Clinical Immunology Congress, showed that ZL-1503 could simultaneously suppress inflammatory and itch-related pathways involved in atopic dermatitis. According to the company, these results support the therapy’s potential as a novel treatment option for patients with moderate to severe disease.
“The progress of ZL-1503 is another strong example of our global development capabilities, underscoring the speed, scientific rigor and operational excellence of our team,” said Rafael G. Amado, M.D., president and head of global research and development at Zai Lab. “Importantly, ZL-1503 has the potential to provide patients with a novel and much-needed treatment option. We are encouraged by the preclinical data and look forward to evaluating its performance in the clinic.”
The Phase 1/1b trial is a randomized, double-blind, placebo-controlled study that includes both single-dose and multiple-ascending-dose cohorts. It is designed to assess safety, tolerability, pharmacokinetics and preliminary efficacy in healthy volunteers and participants with moderate to severe atopic dermatitis.
