Prasugrel 60/10 mg provided greater inhibition of platelet aggregation than clopidogrel 600/75 mg at 2 hours post-loading dose (mean MPA 31% vs 55%, P<0.001).
RCT (n=110)
double-blind
randomized
Does prasugrel improve P2Y12 receptor-mediated platelet inhibition compared to clopidogrel in aspirin-treated patients with stable coronary artery disease?
Prasugrel provides faster onset and greater inhibition of P2Y12 receptor-mediated platelet aggregation than clopidogrel due to more efficient generation of its active metabolite.
Absolute Event Rate: 31% vs 55%
p-value: p=<0.001
AIMS: P2Y(12) receptor antagonism and platelet inhibition by prasugrel vs. clopidogrel were investigated in patients with stable coronary artery disease. METHODS AND RESULTS: One hundred and ten aspirin treated subjects were randomized to double-blind treatment with clopidogrel (n = 55) 600 mg loading dose (LD) and 75 mg maintenance dose (MD) or prasugrel (n = 55) 60 mg LD and 10 mg MD for 28 days. Concentrations of prasugrel and clopidogrel active metabolites were determined. Platelet aggregation to 20 microM adenosine diphosphate, measured by light transmission aggregometry, was reported as maximal platelet aggregation (MPA). P2Y(12) function was assessed by the vasodilator-stimulated phosphoprotein assay and reported as platelet reactivity index (PRI). The same pharmacodynamic measurements were performed after ex vivo addition of clopidogrel's active metabolite. At 2 h post-LD, mean MPA was 31 vs. 55%, and mean PRI 8.3 vs. 55.9% for prasugrel and clopidogrel, respectively (P < 0.001). During MD on day 14 and 28, mean MPA was 42 vs. 54% and mean PRI was 25 vs. 51%, respectively (P < 0.001). Peak level of the active metabolite and P2Y(12) inhibition occurred earlier and was greater with prasugrel (P < 0.001). Mean area under the time-concentration curve (AUC; microM.h) of the respective active metabolite was higher with prasugrel vs. clopidogrel post-LD (1.11 vs. 0.24) and post-MD (0.16 vs. 0.062). Ex vivo addition of clopidogrel's active metabolite further reduced PRI in all patients whose platelets were not already maximally inhibited. CONCLUSION: In aspirin-treated subjects with coronary artery disease, prasugrel 60/10 mg provides faster onset and greater inhibition of P2Y(12) receptor-mediated platelet aggregation than clopidogrel 600/75 mg, because of greater and more efficient generation of the active metabolite.
Wallentin et al. (2007) conducted an RCT in stable coronary artery disease (n=110). prasugrel vs. clopidogrel 600 mg LD and 75 mg MD was evaluated on maximal platelet aggregation (MPA) at 2 h post-LD (p=<0.001). Prasugrel 60/10 mg provided greater inhibition of platelet aggregation than clopidogrel 600/75 mg at 2 hours post-loading dose (mean MPA 31% vs 55%, P<0.001).