Abstract
PURPOSE: HBM9378 (SKB378/WIN378) is a novel monoclonal antibody targeting thymic stromal lymphopoietin (TSLP), characterized by an extended half-life and developed to address the unmet medical need for a more durable and convenient biologic therapy for asthma. This first-in-human (FIH) study was conducted to evaluate the safety, tolerability, pharmacokinetics (PK) and immunogenicity of HBM9378 in healthy subjects, providing essential human data to support further clinical development. PARTICIPANTS AND METHODS: This Phase I study utilized a single ascending dose (SAD) design with randomization, double-blinding, and placebo control. Five dose-escalation cohorts were included: 20 mg, 60 mg, 200 mg, 600 mg, and 900 mg. Each cohort comprised ten healthy subjects, of whom eight received HBM9378 at the assigned dose and two received placebo. Safety was evaluated through monitoring of adverse events and laboratory assessments. Pharmacokinetics (PK) were characterized by calculating and comparison of key PK parameters. Immunogenicity was assessed by determining the incidence of anti-drug antibody (ADA) following administration. RESULTS: The safety profiles of the HBM9378 dose groups were comparable to those of the placebo group with respect to treatment-emergent adverse events (TEAEs), and no dose-dependent increase in safety risk was observed. The median T(max) was 4.05-14.1 days and the mean T(1/2) was 55.0-65.8 days. HBM9378 exposure (C(max) and AUC) increased dose-proportionally across the 20-900 mg dose range, and the ADA incidence during the study was 5% (2/40). CONCLUSION: HBM9378 was well-tolerated and exhibited a prolonged half-life in healthy subjects. These results support further investigation of HBM9378 in patients with severe immunological disorders. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov (NCT05790694) and on the China Center for Drug Evaluation (CDE) platform (CTR20221961).