Radiprodil in Participants With Hepatic Impairment

This is a Phase 1, open-label, two-arm study designed to assess the pharmacokinetics (PK), safety, and tolerability of a single oral dose of radiprodil in adults with varying degrees of hepatic impairment compared with matched healthy participants. Up to 40 participants aged 18 to 75 years will be enrolled across five cohorts. Participants will include individuals with mild (Child-Pugh Class A), moderate (Child-Pugh Class B), or severe (Child-Pugh Class C) hepatic impairment, as well as healthy participants matched for age, sex, and body mass index where feasible. The study consists of a Screening Period (Days -28 to -2), check-in on Day -1, and a Treatment Period. Participants will be confined to the clinical research unit from Day -1 through completion of study assessments on Day 6. On Day 1, all participants will receive a single oral dose of radiprodil 15 mg administered as an oral suspension. Serial blood samples will be collected to determine plasma concentrations of radiprodil and its major metabolites. Key PK parameters include area under the concentration-time curve (AUC), maximum observed concentration (Cmax), time to maximum concentration (Tmax), terminal half-life (t½), apparent clearance (CL/F), and apparent volume of distribution (Vz/F). Safety and tolerability will be evaluated throughout the study by monitoring adverse events, vital signs, electrocardiograms, clinical laboratory tests, physical examinations, and Columbia Suicide Severity Rating Scale assessments. Hepatic impairment can alter the metabolism and exposure of many drugs. Because radiprodil is primarily eliminated via hepatic metabolism, this study is intended to characterize the effect of liver impairment on radiprodil exposure and to inform potential dosing recommendations for future clinical use.