In the HOST-EXAM trial investigators found monotherapy with clopidogrel (in patients who had experienced an event-free 6 to 18 months) following percutaneous coronary intervention (PCI; using a drug-eluting stent) was superior to monotherapy with aspirin, over a 2-year follow-up period. Clopidogrel was associated with both fewer thrombotic and bleeding endpoints.
In patients who have experienced an acute myocardial infarction (MI) and undergone a percutaneous coronary intervention (PCI), guidelines suggest 6 to 12 months of dual antiplatelet therapy (DAPT), typically aspirin plus a P2Y12 inhibitor such as clopidogrel. After the initial 6 to 12 month period, lifetime monotherapy is recommended, and although guidelines do not specify which type of monotherapy, aspirin is the most widely used. Investigators aimed to explore if an alternative monotherapy could achieve superior clinical outcomes as compared with aspirin.
To address this question, the HOST-EXAM study (NCT02044250) randomized 5438 patients who had completed 6-12 months of event-free DAPT following MI and PCI; 2710 (49.8%) participants took P2Y12 inhibitor clopidogrel only, and 2728 (50.2%) took aspirin only. All participants were followed for 24 months.
The primary endpoint was a composite of all-cause death, acute coronary syndrome including non-fatal MI, stroke, the need for revascularization while under antiplatelet therapy, and grade ≥ 3 bleeding academic research consortium (BARC) bleeds. At 2 years, 152 (5.7%) primary endpoint events had occurred in the clopidogrel group, as compared with 207 (7.7%) in the aspirin group (hazard ratio 0.73; 95%CI 0.59-0.70; P=0.0035). Researchers acknowledged some limitations of this trial; it was open-label, and it was conducted only in South Korea; therefore, results may not be generalizable to other ethnicities. Furthermore, most of the enrolled patients had followed a DAPT regimen for about 1 year; therefore, results may not be generalizable to those who have been on DAPT for a shorter period.
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Author: Kelly Schoonderwoerd
Original article: Bon-Kwon K et al. Lancet. 2021 Jun 26;397(10293):2487-2496.