Zai Lab Limited announced positive topline results from a randomized, double-blind, placebo-controlled Phase 1b proof-of-concept and first-in-human study to evaluate the safety, pharmacokinetics, and efficacy of a topical formulation of ZL-1102 in adults with mild-to-moderate chronic plaque psoriasis (CPP). ZL-1102 is an investigational, novel human VH antibody fragment, targeting the IL-17A cytokine and is formulated for topical use. In efficacy data in 51 evaluable patients, Treatment with ZL-1102 showed approximately a 45% relative improvement compared to placebo in the local Psoriasis Area Severity Index (PASI)1 score of the target lesion at four weeks. A trend of increasing efficacy compared to placebo was observed over time, and clinical benefit was maintained after the end of treatment up to six weeks. Anti-inflammatory effects were observed, with clear improvement in erythema of the target lesion up to four weeks, maintained after the end of treatment up to six weeks. Clinical improvement in scaling was also observed. ZL-1102 showed consistent clinical improvement in target lesion size (reduction in area) compared to an area increase in the placebo arm during the treatment period. 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. The responder rate in this study was defined as the percentage of patients who achieved a ?50% reduction compared to baseline in local PASI score of the target lesion, measured weekly. Safety data in 53 evaluable patients showed: A benign safety and tolerability profile comparable to placebo, with treatment-emergent adverse events that were few in number and mild. Pharmacokinetic studies confirmed lack of systemic absorption of the compound.