PURPOSE: Abiraterone acetate (AA) was recently approved for castration-resistant prostate cancer in Japan.
Two phase 1 studies were conducted to assess the pharmacokinetics of abiraterone after single-dose administration in Japanese healthy men and to evaluate the effects of food timing on abiraterone pharmacokinetics after single-dose administration of AA in Japanese and Caucasian healthy men.
METHODS: In the dose-proportionality study, subjects (n = 30 Japanese) were randomly assigned to receive single doses of 250, 500, and 1,000 mg AA, and in the food-timing study, subjects (n = 22 Japanese and n = 23 Caucasian) randomly received single doses of 1,000 mg AA under fasted (overnight) and three different modified fasting conditions.
RESULTS: Mean C max and AUC∞ for abiraterone increased dose-dependently in Japanese healthy men; however, 90 % confidential interval (CI) was outside the predefined dose-proportionality criteria. Based on geometric mean ratios and 90 % CIs (versus overnight fasting condition), abiraterone exposure (AUC) increased significantly with dosing 1 h premeal, 2 h postmeal, or in between two meals 4 h apart by 57 %, 595 %, and 649 %, respectively.
CONCLUSION: No clinically meaningful difference was observed in the pharmacokinetics of abiraterone between Caucasian and Japanese subjects.
Inoue K, Shishido A, Vaccaro N, Jiao J, Stieltjes H, Bernard A, Yu M, Chien C. Are you the author?
Janssen Pharmaceutical, KK, Tokyo, Japan.
Reference: Cancer Chemother Pharmacol. 2014 Oct 25. Epub ahead of print.