A Comparison of Reduced-Dose Prasugrel and Standard-Dose Clopidogrel in Elderly Patients with Acute Coronary Syndromes Undergoing Early Percutaneous Revascularization
Background—Elderly patients are at elevated risk of both ischemic and bleeding complications after an acute coronary syndrome (ACS), and display higher on-clopidogrel platelet reactivity as compared to younger patients. Prasugrel 5 mg provides more predictable platelet inhibition, as compared to clopidogrel, in the elderly, suggesting the possibility of reducing ischemic events without increasing bleeding.
Methods—In a multicenter, randomized, open-label, blinded-endpoint trial, we compared a once daily maintenance dose of prasugrel 5 mg with the standard clopidogrel 75 mg in patients >74 years with ACS undergoing percutaneous coronary intervention (PCI). The primary endpoint was the composite of mortality, myocardial infarction, disabling stroke and re-hospitalization for cardiovascular causes or bleeding within one year. The study was designed to demonstrate superiority of prasugrel 5 mg over clopidogrel 75 mg.
Results—Enrolment was interrupted, according to pre-specified criteria, after a planned interim analysis, when 1443 patients (40% women, mean age 80 years) had been enrolled, with a median follow-up of 12 months, due to futility for efficacy. The primary endpoint occurred in 121 patients (17%) with prasugrel and 121 (16.6%) with clopidogrel (HR 1.007, 95% CI, 0.78-1.30; P =0.955). Definite/probable stent thrombosis rates were 0.7% with prasugrel vs 1.9% with clopidogrel (OR 0.36, C.I. 0.13-1.00, p=0.06). Bleeding Academic Research Consortium types ≥2 were 4.1% with prasugrel vs 2.7% with clopidogrel (OR 1.52, C.I. 0.85-3.16, P= 0.18).
Conclusions—The present study in elderly ACS patients showed no difference in the primary endpoint between reduced-dose prasugrel and standard-dose clopidogrel. However, the study should be interpreted in the light of premature termination of the trial.
Clinical Trial Registration—URL: https://clinicaltrials.gov/ Unique Identifier: NCT01777503
- Received October 10, 2017.
- Revision received January 10, 2018.
- Accepted February 2, 2018.