Pharmacokinetics of Opicapone and Its Metabolites in Healthy White and Chinese Subjects

Abstract Opicapone (OPC) is a third‐generation catechol‐O‐methyltransferase inhibitor developed to treat Parkinson disease and motor fluctuations. This open‐label, single‐center, phase 1 study aimed to evaluate the pharmacokinetics (PK) of OPC and its metabolites when administered as single and multiple doses in healthy White and Chinese subjects. The study enrolled a total of 30 White and Chinese healthy subjects, equally balanced among groups. The first dose of OPC was administered orally as a single dose of 50 mg on day 1, followed by a 10‐day once‐daily treatment from day 5 to day 14. Plasma concentrations of OPC and its metabolites were measured at 0 to 72 and 0 to 144 hours after dosing for single dose and multiple dose, respectively. Moreover, urine concentrations of OPC and its metabolite were measured 0 to 24 hours after dosing. PK parameters were derived from noncompartmental analysis. Geometric mean ratios and 90% confidence intervals for the main PK parameters were conducted to evaluate the ethnic difference between White and Chinese subjects. The plasma and urine exposure of OPC and its metabolites in Chinese subjects were similar to those in White subjects. These results indicated that ethnicity had no significant impact on PK of OPC between White and Chinese subjects.