Zai Lab Reports Early Data for ZL-1503 Eczema Drug
First-in-human results for a long-acting IL-13/IL-31Rα bispecific antibody were presented at ACAAI 2026 in healthy volunteers.
Updated on Nov. 13, 2026 in Asthma
Zai Lab presented first-in-human data for ZL-1503, a long-acting IL-13/IL-31Rα bispecific antibody under evaluation for atopic dermatitis. A single dose produced at least 90% inhibition of an atopic dermatitis signaling biomarker through Week 12 in healthy volunteers.
Why it matters
The results support continued development of a dosing approach with a serum half-life of approximately 40 to 50 days, which could reduce how often patients need treatment. Because the study enrolled healthy volunteers, the findings do not yet show whether the drug improves clinical symptoms.
The phase 1/1b trial (NCT07235384) enrolled 48 healthy volunteers, with doses of 200 mg to 1,000 mg achieving at least 90% inhibition of IL-13-stimulated pSTAT6 at Week 12. Whether these biomarker effects translate into clinical benefit in patients remains unknown.
The players
Zai Lab
Zai Lab is a biopharmaceutical company that developed ZL-1503 and presented its first-in-human data.
American College of Allergy, Asthma & Immunology (ACAAI)
ACAAI is a professional medical society whose annual scientific meeting served as the venue for the data presentation.
The details
ZL-1503 was discovered internally at Zai Lab and incorporates serum half-life extension technology to prolong systemic exposure. Treatment reduced circulating type 2 inflammatory biomarkers TARC, CCL26, and IgE, and no anti-drug antibodies, dose-limiting toxicities or serious adverse events were reported as of the data cutoff.
Timeline
September 2024: FDA approved Eli Lilly's Ebglyss (lebrikizumab) for atopic dermatitis.
December 2024: FDA approved Galderma's Nemluvio (nemolizumab).
November 13, 2026: Zai Lab presented first-in-human ZL-1503 data at ACAAI 2026.
First half of 2027: Expected Part B cohort data for ZL-1503 in patients.
Health Landscape
ZL-1503 follows the same IL-13 and IL-31 pathway logic as Eli Lilly's Ebglyss, approved by the FDA in September 2024, and Galderma's Nemluvio, approved in December 2024. Its differentiator is a serum half-life of approximately 40 to 50 days, aiming to extend the interval between doses.
ZL-1503 is still in early development and is not available to patients. If later studies confirm clinical benefit, a longer-acting option could mean fewer injections for people managing atopic dermatitis.
The takeaway
Early biomarker suppression is a necessary first step, but clinical benefit in patients will determine whether long-acting IL-13 and IL-31 blockade becomes a practical treatment option.
What happens next
Data from the Part B cohort are expected in the first half of 2027, and initial data from the intravenous-to-subcutaneous bioavailability bridging study are expected in 2027.
Further reading
For broader context on related immune-driven conditions, see Asthma.
