Zai Lab has reported positive topline data from Phase Ib clinical trial of a topical formulation of its therapy, ZL-1102, in mild-to-moderate chronic plaque psoriasis (CPP) patients.

Formulated as a hydrogel for topical usage, ZL-1102 is an experimental human VH antibody fragment that acts on the IL-17A cytokine.

The two-part, proof-of-concept, randomised, placebo-controlled, double-blind trial assessed the safety, pharmacokinetics, and efficacy of the therapy.

The open-label Part A segment enrolled six subjects with mild-to-moderate CPP to analyse pharmacokinetics of single-dose ZL-1102.

In the double-blind, placebo-controlled, multicentre Part B segment, the safety, pharmacokinetics and efficacy of ZL-1102 were investigated in 53 subjects. The participants were randomised to receive a twice-daily dose of either topical ZL-1102 or a placebo.

The percentage change from baseline in the local Psoriasis Area Severity Index (PASI) score at day 29 was the primary efficacy goal of Part B.

Change from baseline of local PASI components, target lesion size and responder rates by visit comprised the secondary goals.

According to the efficacy results from 51 evaluable subjects, ZL-1102 demonstrated to offer nearly a 45% relative improvement in the local PASI score of the target lesion versus placebo at four weeks.

A trend of growing efficacy against placebo was reported over time with clinical benefit sustained up to six weeks on concluding the treatment.

In the trial, anti-inflammatory benefits were seen with robust improvement in erythema of the target lesion lasting up to four weeks. This trend sustained up to six weeks on concluding the treatment.

The subjects also had clinical improvement in scaling.

ZL-1102 showed consistently higher responder rates over time compared to placebo up to four weeks and maintained after the end of treatment up to six weeks.

Furthermore, treatment-emergent adverse events were infrequent and mild, with good safety and tolerability profile equivalent to placebo reported in the trial.

The absence of systemic absorption of the compound was established in pharmacokinetic studies.

Zai Lab Autoimmune and Infectious Diseases chief medical officer Harald Reinhart said: “As 70–80% of plaque psoriasis cases are mild-to-moderate in severity, there is a strong rationale and patient need to develop a topical formulation of an IL-17-directed therapy that works directly on the lesion and avoids systemic exposure.

“ZL-1102 is the first IL-17-directed topical treatment for patients with milder forms of chronic plaque psoriasis.”

A common chronic, systemic, inflammatory autoimmune skin disease, plaque psoriasis is marked by red patches and silvery-scaled plaques on the skin.