Aim: Vorapaxar is a proteaseactivated receptor (PAR)-1 antagonist being developed for the prevention and treatment of thrombotic vascular events. To evaluate race/ethnic differences between Caucasians and Chinese in the pharmacokinetics of vorapaxar and its active metabolite SCH 2046273 (M20) or in the metabolite/parent ratio, we conducted a cross-study comparison on pharmacokinetic data of vorapaxar and M20 obtained from two similarly designed studies: one in healthy Chinese subjects and the other in a healthy Western (United States, [U.S.]) population.
Methods: The pharmacokinetic profiles of vorapaxar and M20 were characterized using open label, two treatment parallel group designs in men and women aged 18 - 45 years. Vorapaxar was administered orally as a single dose of 40 mg in Chinese subjects (n = 14) or 120 mg in U.S. subjects (n = 14), or 2.5 mg QD for 6 weeks in both studies (Chinese, n = 14; U.S., n = 23).
Results: Vorapaxar was rapidly absorbed in both Chinese and U.S. subjects. Vorapaxar and M20 had similar elimination half-lives. The range of metabolite/parent ratios after single dose or daily administration was largely overlapped in Chinese and U.S. subjects. Steady state was attained by day 21 for vorapaxar and M20 in both race/ethnic groups. The accumulation ratios for vorapaxar and M20 during daily administration were similar in Chinese and U.S. subjects. Vorapaxar was well-tolerated in Chinese and U.S. subjects.
Conclusion: The pharmacokinetic profiles of vorapaxar and M20 and the metabolite/parent ratios in healthy Chinese were generally comparable to those in a healthy Western population.