Greater Inhibition of Platelet Aggregation and Reduced Response Variability With Prasugrel Versus Clopidogrel: An Integrated Analysis

Multiple studies report response variability to a 300-mg clopidogrel loading dose (LD). Pooled platelet aggregometry data compared responses (change in maximal platelet aggregation [ΔMPA] or inhibition of platelet aggregation [IPA]) to clopidogrel 300-mg (n = 131) or prasugrel 60-mg (n = 109) LDs. Poor responder rates were determined using empiric criteria (IPA < 10% and ΔMPA < 10% for 20 µM and 5 µM adenosine diphosphate [ADP]) and Bayesian model-based criteria (IPA < 20% and ΔMPA < 15% for 20 µM ADP; IPA < 25% and ΔMPA < 20% for 5 µM ADP). Prasugrel achieved greater ΔMPA and IPA from 2 to 24 hours post-LD (P < .001). For 20 µM ADP, poor responder rates for clopidogrel ranged from 17% to 43%; no prasugrel poor responders were observed. Regardless of the criterion, prasugrel 60 mg achieved greater IPA and fewer poor responders than the clopidogrel 300-mg LD.