September 1, 2021 — The STOPDAPT-2 ACS trial does not support the use of one month of dual antiplatelet therapy (DAPT) in acute coronary syndrome (ACS) patients undergoing stent implantation. That was the finding of late-breaking research presented in a Hot Line session at European Society of Cardiology (ESC) Congress 2021.
“One-month DAPT and subsequent clopidogrel monotherapy failed to achieve noninferiority for net clinical benefit compared with standard 12-month DAPT after ACS. There was a trend toward an increase in cardiovascular events despite a reduction in major bleeding events," explained study author Dr. Hirotoshi Watanabe of Kyoto University, Japan.
The STOPDAPT-2 trial previously demonstrated that among patients undergoing percutaneous coronary intervention (PCI), one month of DAPT followed by clopidogrel monotherapy resulted in a significantly lower rate of a composite of cardiovascular and bleeding events, compared with 12 months of DAPT with aspirin and clopidogrel. In that trial, 62% of patients had stable coronary artery disease and 38% had ACS.
To generate sufficient statistical power to compare the effect of the two treatments in ACS patients alone, the STOPDAPT-2 ACS trial enrolled 2,988 ACS patients and pooled the results with the 1,148 ACS patients in STOPDAPT-2 – for a total of 4,136 patients. Both trials used the same protocol. Participants were randomly assigned in a 1:1 ratio to one-month DAPT followed by clopidogrel monotherapy or 12-month DAPT after PCI with cobalt-chromium everolimus-eluting stents.
The primary outcome was a composite of cardiovascular and bleeding outcomes at one year: death from cardiovascular causes, myocardial infarction, definite stent thrombosis, ischemic or hemorrhagic stroke, and Thrombolysis in Myocardial Infarction (TIMI) major or minor bleeding.
The two major secondary endpoints were: 1) a cardiovascular composite outcome (death from cardiovascular causes, myocardial infarction, definite stent thrombosis, ischemic or hemorrhagic stroke); and 2) TIMI major or minor bleeding.
The primary outcome occurred in 65 patients (3.2% one-year cumulative incidence) assigned to one-month DAPT and 58 patients (2.83%) assigned to 12-month DAPT (hazard ratio [HR] 1.14; 95% confidence interval [CI] 0.80–1.62; p=0.06 for noninferiority).
The major secondary cardiovascular outcome occurred in 56 (2.76%) patients in the one-month DAPT group and 38 (1.86%) patients in the 12-month DAPT group (HR 1.5; 95% CI 0.99–2.26). The major secondary bleeding outcome occurred in 11 (0.54%) patients allocated to one-month DAPT and 24 (1.17%) patients allocated to 12-month DAPT (HR 0.46; 95% CI 0.23-0.94).
2. Watanabe H, Domei T, Morimoto T, et al. Effect of 1-month dual antiplatelet therapy followed by clopidogrel vs 12-month dual antiplatelet therapy on cardiovascular and bleeding events in patients receiving PCI: The STOPDAPT-2 Randomized Clinical Trial. JAMA. 2019;321:2414–2427.