Rivaroxaban for pulmonary embolism

Rivaroxaban, Janssen's oral factor Xa inhibitor, may be an effective alternative to heparin/warfarin for treatment of symptomatic pulmonary embolism, according to a new study. The drug is currently approved for the prevention of stroke in patients with nonvalvular atrial fibrillation and for deep vein thrombosis (DVT) prophylaxis following hip replacement. It has also been shown to be an effective treatment for DVT, although it is not approved for this indication. The new study was a randomized, open-label, event-driven, noninferiority trial comparing rivaroxaban to standard therapy with enoxaparin followed by adjusted-dose vitamin K antagonist for 3, 6, or 12 months for the treatment of pulmonary embolism. The primary outcome was symptomatic recurrent venous thromboembolism with a secondary safety outcome of clinically relevant nonmajor bleeding. In more than 4800 patients who were randomized, rivaroxaban was noninferior to standard therapy with 50 events in the rivaroxaban group (2.1%) vs 44 events in the standard therapy group (1.8%) (hazard ratio [HR], 1.12; confidence interval [CI] 0.75 to 1.68, noninferiority margin 2.0; P = 0.003). The principal safety outcome occurred in 10.3% of patients in the rivaroxaban group and 11.4% of those in the standard therapy group, while major bleeding occurred in 26 patients (1.1%) in the rivaroxaban group and 52 patients (2.2%) in the standard therapy group (HR 0.49; 95% CI, 0.31 to 0.79; P = 0.003). The authors conclude that a fixed-dose regimen of rivaroxaban was noninferior to standard therapy with enoxaparin and warfarin for the initial and long-term treatment of pulmonary embolism, and potentially showed an improved benefit-risk profile (N Engl J Med published online March 26, 2012). The doses of rivaroxaban used in the study were 15 mg twice a day for 3 weeks followed by 20 mg once daily for the duration. Rivaroxaban offers the advantage of oral therapy compared to enoxaparin and the lack of need for blood test monitoring compared to warfarin.