Clinical outcomes for prasugrel versus clopidogrel in patients with unstable angina or non-ST-elevation myocardial infarction: an analysis from the TRITON-TIMI 38 trial

Aims: In the TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel Thrombolysis In Myocardial Infarction 38 (TRITON-TIMI 38), prasugrel reduced the primary ischaemic endpoint as compared with clopidogrel in acute coronary syndrome (ACS) patients planned to undergo percutaneous coronary interventions, but increased the risk of bleeding. The present analysis shows the efficacy and safety data for the 10,074 non-ST segment elevation (NSTE)-ACS patients included in that trial.

Methods and results: The primary endpoint was significantly reduced by prasugrel in the overall NSTE-ACS population (hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.73-0.93, p=0.002) as well as in unstable angina (UA) and in non-ST elevation myocardial infarction (NSTEMI) patient subgroups (interaction p value=0.39). Although non-coronary artery bypass graft (CABG) TIMI major bleeding was increased with prasugrel as compared with clopidogrel (HR 1.40, 95% CI 1.05-1.88, p=0.02), there was a net clinical benefit in patients assigned to prasugrel (HR 0.89, 95% CI 0.80-1.00, p=0.043), which was consistent for UA and NSTEMI subgroups (interaction p value=0.84 and 0.72). In patients who met the criteria for prasugrel use recommended by the European Medicines Agency, thus excluding from the analysis patients with prior transient ischemic attack (TIA)/stroke, with weight <60 kg or age ≥75 years, and censoring follow-up at 365 days, (European Union (EU)-label cohort) prasugrel showed superiority over clopidogrel with regard to the primary endpoint (HR 0.73, 95% CI 0.63-0.85, p<0.0001) for the entire NSTE-ACS population, as well as for UA patients and NSTEMI patients without significant differences in non-CABG TIMI major bleeding.

Conclusion: Prasugrel, as compared with clopidogrel, significantly reduced the primary endpoint of the TRITON-TIMI 38 trial in NSTE-ACS patients, as well as in the UA and NSTEMI groups. A significant reduction in the primary endpoint without increased bleeding was observed in the EU-label cohort.