Zai Lab Limited reports preclinical data showing its bispecific antibody ZL-1503 delivers sustained suppression of itch and inflammation in atopic disease models, supporting ongoing Phase 1/1b trials.
Written By: Mahathi Palivela, PharmD
Reviewed By: Pharmacally Editorial Team
Zai Lab Limited reported preclinical data for its investigational bispecific antibody ZL-1503 at IMMUNOLOGY2026, demonstrating sustained suppression of itch and inflammation in models of atopic disease.
ZL-1503 is designed to simultaneously target interleukin-13 (IL-13), a driver of type 2 inflammation, and interleukin-31 receptor alpha (IL-31Rα), which mediates pruritus and amplifies immune responses.
By inhibiting both pathways, the therapy aims to disrupt the itch–scratch–inflammation cycle that underlies conditions such as atopic dermatitis.
In the study, a single intravenous dose of ZL-1503 produced dose-dependent inhibition of IL-31-induced scratching and IL-13 signaling, with effects sustained for up to 112 days. A single dose of 10 mg/kg also improved lung function, reduced airway inflammation in asthma models, and alleviated symptoms of allergic rhinitis and conjunctivitis.
Transcriptomic and histopathological analyses showed suppression of T helper 2-driven inflammatory pathways, reduced immune cell infiltration, and decreased mast cell activation across affected tissues. The therapy demonstrated a favorable nonclinical safety profile, supporting its continued development.
According to Rafael G. Amado, President and Head of Global Research and Development at Zai Lab, the breadth and durability of activity observed in these models support the rationale for dual targeting of IL-13 and IL-31 pathways and reinforce the advancement of ZL-1503 into clinical studies.
The company initiated a Phase 1/1b trial in December 2025 to evaluate safety, tolerability, pharmacokinetics, and early efficacy in healthy volunteers and patients with moderate-to-severe atopic dermatitis across Australia, New Zealand, and China.
Reference
About the Writer
Mahathi Palivela is pursuing PharmD and has a strong interest in Clinical Pharmacy and Patient safety. She is passionate about handling and analyzing patient data, and translating clinical insights into clear, meaningful summaries. She aims to apply this interest in Medical Writing and Pharmacovigilance, focusing on improving patient outcomes through careful data interpretation and communication .