Benefit of Switching Dual Antiplatelet Therapy After Acute Coronary Syndrome: the TOPIC (timing of Platelet Inhibition After Acute Coronary Syndrome) Randomized Study

Aims: Newer P2Y12 blockers (prasugrel and ticagrelor) demonstrated significant ischaemic benefit over clopidogrel after acute coronary syndrome (ACS). However, both drugs are associated with an increase in bleeding complications. The objective of the present study was to evaluate the benefit of switching dual antiplatelet therapy (DAPT) from aspirin plus a newer P2Y12 blocker to aspirin plus clopidogrel 1 month after ACS.

Methods And Results: We performed an open-label, monocentric, and randomized trial. From March 2014 to April 2016, patients admitted with ACS requiring coronary intervention, on aspirin and a newer P2Y12 blocker and without adverse event at 1 month, were assigned to switch to aspirin and clopidogrel (switched DAPT) or continuation of their drug regimen (unchanged DAPT). The primary outcome was a composite of cardiovascular death, urgent revascularization, stroke and bleeding as defined by the Bleeding Academic Research Consortium (BARC) classification ≥2 at 1 year post ACS. Six hundred and forty six patients were randomized and 645 analysed, corresponding to 322 patients in the switched DAPT and 323 in the unchanged DAPT group. The primary endpoint occurred in 43 (13.4%) patients in the switched DAPT group and in 85 (26.3%) patients in the unchanged DAPT (HR 95%CI 0.48 (0.34-0.68), P < 0.01). No significant differences were reported on ischaemic endpoints, while BARC ≥ 2 bleeding occurred in 13 (4.0%) patients in the switched DAPT and in 48 (14.9%) in the unchanged DAPT group (HR 95%CI 0.30 (0.18-0.50), P < 0.01).

Conclusion: A switched DAPT is superior to an unchanged DAPT strategy to prevent bleeding complications without increase in ischaemic events following ACS.