A new study has failed to confirm the non-inferiority of one month of dual antiplatelet therapy (DAPT) in acute coronary syndrome (ACS) patients undergoing stent implantation compared to standard 12-month DAPT.
Presented at the European Society of Cardiology (ESC) 2021 meeting, the STOPDAPT-2 study compared one-month DAPT followed by clopidogrel monotherapy or 12-month DAPT after PCI with cobalt-chromium everolimus-eluting stents.
The study enrolled 4,136 patients with ACS undergoing PCI, who were followed up at 12 months for the primary outcome of a composite of cardiovascular and bleeding outcomes at one year (death from cardiovascular causes, myocardial infarction, definite stent thrombosis, ischaemic or haemorrhagic stroke, and TIMI major or minor bleeding).
The primary outcome occurred in 3.20% of patients assigned to one-month DAPT and clopidogrel monotherapy versus 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 two major secondary endpoints were: 1) a cardiovascular composite outcome; and 2) TIMI major or minor bleeding.
A secondary cardiovascular composite outcome (death from cardiovascular causes, myocardial infarction, definite stent thrombosis, ischaemic or haemorrhagic stroke) occurred in 2.76% patients in the one-month DAPT group and 1.86% of patients in the 12-month DAPT group (HR 1.50; 95% CI 0.99–2.26).
The major secondary bleeding outcome occurred in 0.54% patients allocated to one-month DAPT and 1.17% of patients allocated to 12-month DAPT (HR 0.46; 95% CI 0.23-0.94).
The study investigators said a previous STOPDAPT trial had demonstrated better outcomes for one month of DAPT followed by clopidogrel monotherapy compared with 12 months of DAPT with aspirin and clopidogrel after PCI, although that trial had 62% of patients with stable coronary artery disease and 38% had ACS.
The STOPDAPT-2 ACS trial with only ACS patients using the same protocol had failed to achieve noninferiority for net clinical benefit compared with standard 12-month DAPT after ACS, concluded study investigator Dr. Hirotoshi Watanabe of Kyoto University, Japan.
“There was a trend toward an increase in cardiovascular events despite a reduction in major bleeding events, he said.
Dr Watanabe added that clopidogrel might not be the optimal P2Y12 inhibitor for monotherapy after PCI in ACS patients, and more potent agents such as prasugrel or ticagrelor may be used instead.