Rivaroxaban received FDA approval on November 4, 2011 for stroke prevention in patients with nonvalvular atrial fibrillation. Results from the ROCKET-AF trial demonstrated that rivaroxaban was noninferior to warfarin for the prevention of stroke or systemic embolism without a significant difference in the risk for major bleeding. The double-blind trial compared rivaroxaban, a direct factor Xa inhibitor, 20 mg/day (or 15 mg/day for those with decreased renal function) vs dose-adjusted warfarin in 14,264 patients with nonvalvular atrial fibrillation. The primary efficacy endpoint, a composite of ischemic or hemorrhagic stroke and systemic embolism, occurred in 188 patients in the rivaroxaban group (1.7%/year) and 241 patients in the warfarin group (2.2%/year) (P < .0001 for noninferiority). Rivaroxaban demonstrated significant reductions in intracranial hemorrhage (0.5% vs 0.7%, P = .02) and fatal bleeding (0.2% vs 0.5%, P = .003) compared with warfarin. However, major gastrointestinal bleeding was more common with rivaroxaban (3.2%) than with warfarin (2.2%) (P < .001).
Rivaroxaban was approved earlier this year for the prevention of deep vein thrombosis and pulmonary embolism following knee or hip replacement surgery. Low-dose rivaroxaban may also reduce death after acute coronary syndrome and is being considered for this indication as well.
Apixaban, another direct factor Xa inhibitor, demonstrated superiority to warfarin in preventing stroke or systemic embolism in the randomized, double-blind ARISTOTLE trial. It also caused less bleeding and had lower mortality. Apixaban (5 mg/day twice daily) or dose-adjusted warfarin were administered to 18,201 patients who had atrial fibrillation and at least 1 additional risk factor for stroke. After a median duration of 1.8 years, 1.27% of the apixaban group vs 1.60% of the warfarin group reached the primary outcome of stroke or systemic embolism (P < .001 for noninferiority, P = .01 for superiority). Major bleeding was lower with apixaban (2.13%/year) compared with warfarin (3.09%/year), P < .001. The rate of hemorrhagic stroke was significantly lower with apixaban, 0.24%/year vs. 0.47%/year with warfarin (P < .001). The rates of ischemic or uncertain type of stroke were not significantly different. Adverse events occurred in similar numbers in both treatment groups. Barring any surprises, FDA approval is expected in the next few months.
Medscape Neurology © 2011 WebMD, LLC
Cite this: Andrew N. Wilner. The Year in Neurology: Studies Not to Miss From 2011 - Medscape - Nov 23, 2011.