Apixaban: an emerging oral factor Xa inhibitor.

Apixaban, an oral direct factor Xa inhibitor, is currently in late stage clinical development for the prevention and treatment of thromboembolic diseases. In comparison with current treatment standards for venous thromboembolism (VTE) prophylaxis, apixaban has shown decreased rates of clinically significant bleeding with mixed results in terms of non-inferiority for VTE events. Secondary treatment of VTE with apixaban is currently in phase III clinical study after earlier trials showed comparable safety and efficacy outcomes. The APPRAISE-1 trial, a phase II investigation of apixaban versus placebo following acute coronary syndrome showed a higher risk of clinically significant bleeding in addition to a trend toward decreased ischemic events. A large, international phase III clinical study (APPRAISE-2) of apixaban following acute coronary syndrome is currently underway. Large, phase III studies testing apixaban for the prevention of vascular events in subjects with non-valvular atrial fibrillation are also ongoing.