No Pharmacokinetic Drug-Drug Interaction Between Prasugrel and Vorapaxar Following Multiple-Dose Administration in Healthy Volunteers

Vorapaxar is a first-in-class antagonist of the protease-activated receptor-1, the primary thrombin receptor on human platelets, which mediates the downstream effects of thrombin in hemostasis and thrombosis. Prasugrel is a platelet inhibitor that acts as a P2Y12 receptor antagonist through an active metabolite, R-138727. This study investigated the interaction of these 2 platelet antagonists when coadministered. This was a randomized, open-label, multiple-dose study in 54 healthy volunteers consisting of a fixed-sequence crossover and a parallel group design. In sequence 1, 36 subjects received prasugrel 60 mg on day 1 and then prasugrel 10 mg once daily on days 2 to 7, followed by vorapaxar 40 mg and prasugrel 10 mg on day 8 and then vorapaxar 2.5 mg and prasugrel 10 mg orally once daily on days 9 to 28. In sequence 2, 18 subjects received vorapaxar 40 mg on day 1 and then vorapaxar 2.5 mg once daily on days 2 to 21. The geometric mean ratios (90% confidence intervals) for AUC(tau) and C-max of coadministration/monotherapy for vorapaxar (0.93 ng.h/mL[0.85-1.02 ng.h/mL] and 0.95 ng/mL [0.86-1.05 ng/mL]) and R-138727 (0.91 ng.h/mL [0.85-0.99 ng.h/mL] and 1.02 ng/mL [0.89-1.17 ng/mL]) were within prespecified bounds, demonstrating the absence of a pharmacokinetic interaction between vorapaxar and prasugrel. There was no specific safety or tolerability risk associated with multiple-dose coadministration of vorapaxar and prasugrel. In conclusion, in this study in healthy volunteers, there was no pharmacokinetic drug-drug interaction between vorapaxar and prasugrel. Multiple-dose coadministration of the 2 drugs was generally well tolerated.