Clopidogrel Versus Aspirin Monotherapy Beyond 1 Year After PCI: The Final 5-Year Results of the STOPDAPT-2 ACS and STOPDAPT-2 Total Cohort.

BACKGROUND: Clopidogrel may have ischemic benefit over aspirin as long-term monotherapy in patients receiving percutaneous coronary intervention.

METHODS: Both the STOPDAPT-2 (Short and Optimal Duration of Dual Antiplatelet Therapy-2) and STOPDAPT-2 ACS (Short and Optimal Duration of Dual Antiplatelet Therapy-2 Study for the Patients With Acute Coronary Syndrome) were multicenter, open-label, adjudicator-blinded, randomized clinical trials in Japan, with the same protocol except that the STOPDAPT-2 ACS enrolled patients with acute coronary syndrome, exclusively. The patients after percutaneous coronary intervention with cobalt-chromium everolimus-eluting stents were randomized into 1-month dual antiplatelet therapy followed by clopidogrel monotherapy (clopidogrel group) or 12-month dual antiplatelet therapy followed by aspirin monotherapy (aspirin group). Follow-up duration was 5 years. The clinical effect between clopidogrel and aspirin monotherapy was compared by the 1-year landmark analysis in the STOPDAPT-2 ACS and STOPDAPT-2 total cohort, a pooled cohort of the 2 trials. The primary end point was the composite of cardiovascular end point (cardiovascular death, myocardial infarction, stroke, or definite stent thrombosis) and bleeding end point (Thrombolysis in Myocardial Infarction major/minor). The major secondary end points were each of the cardiovascular composite end point and the bleeding end point.

RESULTS: Of 2986 patients (clopidogrel group: 1492, aspirin group: 1494) in the 5-year analysis of the STOPDAPT-2 ACS, 2875 (96.3%) completed follow-up. By the 1-year landmark analysis, clopidogrel group was superior to aspirin group for both the primary end point (6.18% and 8.27%; hazard ratio, 0.75 [95% CI, 0.57-0.997]; P=0.048) and the major secondary cardiovascular end point (4.73% and 6.77%; hazard ratio, 0.70 [95% CI, 0.51-0.96]; P=0.03). In the STOPDAPT-2 total cohort, including 5991 patients, the superiority of clopidogrel over aspirin for the cardiovascular end point was highly significant (hazard ratio, 0.74 [95% CI, 0.60-0.91]; P=0.004), although the superiority on the primary end point was insignificant (hazard ratio, 0.86 [95% CI, 0.72-1.03]; P=0.11). There was no between-groups difference in the major secondary bleeding end point, both in the STOPDAPT-2 ACS and STOPDAPT-2 total cohort.

CONCLUSIONS: Clopidogrel monotherapy was superior to aspirin monotherapy for cardiovascular outcomes beyond 1 year after percutaneous coronary intervention, without increased bleeding risk.

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02619760 and NCT03462498.