Aspirin-Free Prasugrel Monotherapy After Percutaneous Coronary Intervention in Patients With Non-ST Elevation Acute Coronary Syndrome

Background: In the presence of a potent P2Y12 inhibitor such as prasugrel, the additional clinical antithrombotic benefit of aspirin is unclear. The feasibility of prasugrel monotherapy without aspirin after percutaneous coronary intervention (PCI) has been demonstrated in chronic coronary syndrome, but is yet to be assessed in patients with non-ST elevation acute coronary syndrome (NSTE-ACS) and low anatomical complexity. Methods and Results: ASET-Japan is a single-arm study investigating the safety of prasugrel 12-month monotherapy with a locally approved dose (loading 20mg; maintenance 3.75mg), started immediately after successful PCI using platinum-chromium everolimus-eluting SYNERGY stents. The primary ischemic endpoint is a composite of cardiac death, spontaneous target vessel myocardial infarction, or definite stent thrombosis; the primary bleeding endpoint is Bleeding Academic Research Consortium (BARC) Type 3 and 5 bleeding. ASET-Japan recruited 101 NSTE-ACS patients from 11 Japanese sites. The mean (±SD) age was 69.1±12.3 years and 36.6% had a PRECISE-DAPT score >25. The mean anatomical SYNTAX score was 7.9±4.7. At 1 year, the primary ischemic endpoint occurred in 1 patient (1.0%; cardiac death). Two BARC Type 3a bleeding events occurred (2.0%): 1 due to a gastric ulcer and 1 to a descending colon malignancy. Conclusions: Low-dose (3.75mg/day) prasugrel monotherapy started immediately after SYNERGY stent deployment was feasible and safe in selected NSTE-ACS patients.