Rivaroxaban seems to reduce the risk of recurrent venous thromboembolism (VTE) without increased risk of bleeding, even when used continuously at low doses (10-20 mg), according to results from the Reduced-dosed Rivaroxaban in the Long-term Prevention of Recurrent Symptomatic Venous Thromboembolism (EINSTEIN CHOICE) study presented at the 2017 American College of Cardiology Annual Scientific Session.
The randomized, double-blind, phase III EINSTEIN CHOICE trial assigned patients to receive either rivaroxaban 10 mg or 20 mg daily or aspirin 100 mg daily for 12 months. Patients were 18 years of age or older, had previously completed 6-12 months of anticoagulation therapy, and were in equipoise for continuing anticoagulation. The efficacy endpoint was fatal or nonfatal symptomatic recurrent VTE and the safety endpoint was major bleeding.
Recurrent VTE occurred in 17 of 1,107 patients (1.5%) receiving rivaroxaban 20 mg daily (therapeutic dose) and in 13 of the 1,127 patients (1.2%) receiving rivaroxaban 10 mg daily. The incidence of VTE was nearly three times higher among the aspirin-treated patients (n=50/1,131; 4.4%).
Both rivaroxaban doses were superior to aspirin in the primary efficacy endpoint (hazard ratio [HR] = 0.34 [95% CI 0.20-0.59] for rivaroxaban 20 mg vs. aspirin; HR=0.26 [95% CI 0.14-0.47] for rivaroxaban 10 mg vs. aspirin; p<0.001 for both comparisons), but there was no significant difference in bleeding among the three treatment groups.
The authors are planning a follow-up study to explore whether low-dose rivaroxaban is equally effective in other patient populations, since the patients enrolled in EINSTEIN CHOICE were younger than the typical patient with VTE, which may limit the generalizability of the study results.
Source: Weitz JI, Lensing AWA, Prins MH, et al. Rivaroxaban or aspirin for extended treatment of venous thromboembolism. N Eng J Med. 2017 March 18. [Epub ahead of print]