Phase 1 study of the effect of icosapent ethyl on warfarin pharmacokinetic and anticoagulation parameters.

Background And Objective: Icosapent ethyl (IPE) is a high-purity prescription form of eicosapentaenoic acid (EPA) ethyl ester approved to reduce triglyceride levels in patients with severe (≥5.65 mmol/L) hypertriglyceridemia. EPA, the active metabolite of IPE, is mainly metabolized via β-oxidation, and studies suggest that omega-3 fatty acids such as EPA may have antithrombotic effects. The objective of this study was to evaluate the effect of IPE on the pharmacokinetic and anticoagulation pharmacodynamics of warfarin, a substrate of cytochrome P450 2C9-mediated metabolism.

Methods: Healthy adults received oral warfarin (25 mg) on day 1, oral IPE (4 g/day) on days 8-35, and co-administration on Day 29. Primary pharmacokinetic end points were area under the concentration-versus-time curve from zero to infinity (AUC(0-∞)) and maximum plasma concentration (C(max)) for R- and S-warfarin; pharmacodynamic end points were area under the international normalized ratio (INR) effect-time curve after the warfarin dose (AUC(INR)) and maximum INR (INR(max)).

Results: Twenty-five subjects completed the study. AUC(0-∞) and C max ratios of geometric means for both R- and S-warfarin following co-administration of warfarin with versus without IPE were within the 90 % confidence intervals of 0.80-1.25. AUC(INR), INR(max), and ratios were also similar.

Conclusions: IPE 4 g/day did not significantly change the single-dose AUC(0-∞) or C(max) of R- and S-warfarin or the anticoagulation pharmacodynamics of warfarin when co-administered as racemic warfarin at 25 mg. Co-administration of these drugs was safe and well tolerated in this study of healthy adult subjects.