Pharmacokinetics and Bioequivalence of Abiraterone Acetate Tablets in Healthy Chinese Volunteers: An Open, Randomized, Single-Dose, Three-Period, Three-Sequence Crossover Study

Background and Objective Abiraterone acetate tablet is an inhibitor of androgen synthesis, primarily for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This study evaluated the bioequivalence and pharmacokinetics of the reference and test formulations of abiraterone acetate tablets in healthy Chinese volunteers. Methods A single-center, open, single-dose, randomized, three-period, three-sequence, semi-repeat (only repeated reference formulations), and reference formulation-corrected fasting reference-scaled average bioequivalence test was conducted in 36 healthy volunteers included in this study. Volunteers were randomly assigned to one of three groups in a 1:1:1 ratio. There was a minimum 7-day washout period between each dose. Blood samples were collected at prescribed time intervals, the plasma concentration of abiraterone acetate tablets was determined by liquid chromatography-tandem mass spectrometry, and adverse events were recorded. Results Under fasting conditions, the maximum plasma concentration (C-max) was 27.02 +/- 14.21 ng/mL, area under the concentration-time curve from time zero to time t (AUC(t)) was 125.30 +/- 82.41 h.ng/mL, and AUC from time zero to infinity (AUC(infinity)) was 133.70 +/- 83.99 h.ng/mL. The 90% confidence intervals (CIs) of the geometric mean ratio (GMR) of AUC(t) and AUC(infinity) were in the range of 0.8000-1.2500, and the coefficient of variation (CVWR) of C-max was more than 30%. The Critbound result was - 0.0522, and the GMR was between 0.8000 and 1.2500. Conclusion Both test and reference formulations of abiraterone acetate tablets were bioequivalent in healthy Chinese subjects under fasting conditions.