New indication: FDA approved rivaroxaban once-daily oral tablets to reduce the risk of stroke and systemic embolism in patients with nonvalvular AF.
Atrial fibrillation (AF) occurs in >2 million Americans and is one of the most common forms of abnormal heart rhythm. On November 4, 2011, FDA approved rivaroxaban once-daily oral tablets to reduce the risk of stroke and systemic embolism in patients with nonvalvular AF. Activation of factor X via the intrinsic and extrinsic coagulation pathways plays an important role in blood clotting. Rivaroxaban is an orally bioavailable factor Xa inhibitor.
Efficacy. Rivaroxaban's efficacy was established in a multicenter, randomized, double-blind, double-dummy, event-driven trial dubbed the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF). The trial enrolled 14,264 adults with AF and a moderate-to-high risk of stroke (87% with a CHADS2 score >3, mean of 3.5). Trial participants were randomly assigned to receive 20 mg (or 15 mg if their creatinine clearance (CrCl) was between 15 and 50 mL/min) of rivaroxaban once daily or adjusted-dose warfarin (target INR of 2.0-3.0; time-in-the-therapeutic range ~55% overall and 64% in North America). In the intention-to-treat analysis, the time to first occurrence of stroke or non-CNS systemic embolism occurred in 269 patients in the rivaroxaban group (2.1% per year) and in 306 patients in the warfarin group (2.4% per year) (HR=0.88; 95% CI, 0.74–1.03), confirming non-inferior efficacy of rivaroxaban to warfarin.
Safety. In the ROCKET AF trial, the most common adverse event seen was bleeding, which could be serious or fatal. Major and nonmajor clinically relevant bleeding occurred in 1,475 patients in the rivaroxaban group (14.9% per year) and in 1,449 in the warfarin group (14.5% per year) (HR=1.03; 95% CI, 0.96–1.11), with significant reductions in intracranial hemorrhage (0.5% vs 0.7%, P=.02) and fatal bleeding (0.2% vs 0.5%, P=.003) in the rivaroxaban group. Concomitant use of drugs affecting coagulation (eg, platelet aggregation inhibitors, other antithrombotic agents, fibrinolytic therapy, thienopyridines, and chronic use of nonsteroidal anti-inflammatory drugs) may increase the risk of bleeding. As with other anticoagulants, epidural or spinal hematomas may occur in patients who are receiving neuraxial anesthesia or undergoing spinal puncture. Rivaroxaban is contraindicated in patients with active major bleeding and in patients with a prior hypersensitivity reaction to the medication. Since discontinuing rivaroxaban increases the risk of thrombotic events, prescribers should consider another anticoagulant unless cessation occurs due to pathological bleeding.