Is it Safe to Replace Aspirin With Low-Dose Rivaroxaban in DAPT?

Low-dose rivaroxaban vs. aspirin added to P2Y12 inhibitor was evaluated
Low-dose rivaroxaban vs. aspirin added to P2Y12 inhibitor was evaluated

WASHINGTON, DC—At the ACC.17 Scientific Session, Erik Magnus Ohman, from Duke Clinical Research Institute, Durham, NC, presented findings from the GEMINI-ACS-1 trial that evaluated the safety of low-dose rivaroxaban vs. aspirin daily in addition to a P2Y12 inhibitor (clopidogrel or ticagrelor) for acute coronary syndrome (ACS) patients. 

The current standard of treatment for patients with ACS is dual antiplatelet therapy (DAPT; aspirin + P2Y12 inhibitor). Rivaroxaban, a Factor Xa inhibitor, has shown to cut mortality and ischemic events when added to DAPT but has been associated with a higher risk of bleeding. 

"The safety of a dual pathway antithrombotic approach combining low-dose rivaroxaban (in place of aspirin) with a P2Y12 inhibitor has not been evaluated," explained Ohman. The Phase 2, double-blind, randomized trial looked at rivaroxaban 2.5mg twice daily vs. aspirin 100mg daily in addition to clopidogrel or ticagrelor for ACS patients (STEMI, NSTEMI, and unstable angina) when initiated 2–10 days after presentation and continued for 6–12 months. The administration of clopidogrel or ticagrelor during the trial was not randomized and was based on investigator preference. 

"The primary endpoint was non-CABG TIMI clinically significant bleeding (major, minor, or requiring medical attention)," said Ohman. The composite efficacy endpoint was CV death, myocardial infarction (MI), ischemic stroke, or definite stent thrombosis. 

The study randomized 3,037 patients with ACS from April 2015–February 2016. The median age in the rivaroxaban group (n=1,519) was 62 years and the median age in the aspirin group (n=1,518) was 63 years. Prior MI was seen in 21% and 23% of patients, respectively. In addition, 87% of patients in each group were treated with percutaneous coronary intervention (PCI) for the index ACS event. 

The median duration of treatment was 291 days. Ohman and coauthors observed a similar risk of TIMI non-CABG clinically significant bleeding with rivaroxaban vs. aspirin (5% in each group; hazard ratio [HR] 1.09, 95% CI: 0.80–1.50; P=0.5840). The risk of composite ischemic outcomes were also similar.

Overall, the dual pathway antithrombotic therapy approach of combining low-dose rivaroxaban + P2Y12 inhibitor for treating ACS patients demonstrated similar risk of clinically significant bleeding as aspirin + P2Y12 inhibitor. Ohman concluded, "Defining best intensity of antithrombotic therapy while patients transition from an antithrombotic setting to chronic prevention deserves more research."