Pharmacokinetics and pharmacodynamics of prasugrel in subjects with moderate liver disease

BACKGROUND AND OBJECTIVE: Prasugrel is a thienopyridine antiplatelet agent under investigation for the prevention of atherothrombotic events in patients with acute coronary syndrome who undergo percutaneous coronary intervention. Patients with chronic liver disease are among those in the target population for prasugrel. As hepatic enzymes play a key role in formation of prasugrel's active metabolite, hepatic impairment could affect the safety and/or efficacy of prasugrel in such patients. METHODS: This was a parallel-design, open-label, multiple dose study of 30 subjects, 10 with moderate hepatic impairment (Child-Pugh Class B) and 20 with normal hepatic function. Prasugrel was administered orally as a 60-mg loading dose (LD) and daily 10-mg maintenance doses (MDs) for 5 days. Pharmacokinetic parameters (AUC(0-t), C(max) and t(max)) and maximal platelet aggregation (MPA) by light transmission aggregometry were assessed after the LD and final MD. RESULTS AND DISCUSSION: Exposure to prasugrel's active metabolite was comparable between healthy subjects and those with moderate hepatic impairment. Point estimates for the ratios of geometric least square means for AUC(0-t) and C(max) after the LD and last MD ranged from 0.91 to 1.14. MPA to 20 microm ADP was similar between subjects with moderate hepatic impairment and healthy subjects for both the LD and MD. Prasugrel was well tolerated by all subjects, and adverse events were mild in severity. CONCLUSION: Moderate hepatic impairment appears to have no effect on exposure to prasugrel's active metabolite. Furthermore, MPA results suggest that moderate hepatic impairment has little or no effect on platelet aggregation relative to healthy controls. Overall, these results suggest that a dose adjustment would not be required in moderately hepatically impaired patients taking prasugrel.