A New Oral Direct Factor Xa Inhibitor

Edoxaban is an oral direct factor Xa inhibitor that is currently undergoing investigation in phase III clinical trials for the prevention of stroke in patients with atrial fibrillation (AF) and for the prevention and treatment of venous thromboembolic events (VTE). Factor Xa is an attractive target for anticoagulant treatment, as it is the primary and rate-limiting source of amplification in the coagulation cascade. Edoxaban is a competitive inhibitor of factor Xa and has >10 000-fold greater selectivity for factor Xa relative to thrombin. In phase I clinical trials, the anticoagulant effects of edoxaban included dose-dependent increases in activated partial thromboplastin time and prothrombin time following single edoxaban doses of 10-150 mg and after multiple ascending doses (60 mg twice daily, 90 mg daily and 120 mg daily). The anticoagulant effects of edoxaban were rapid in onset (time to peak plasma concentration 1-2 hours) and sustained for up to 24 hours. Prolongation of bleeding time in 8% of subjects was >9.5 minutes (none of which appeared to be clinically significant) 2 hours after initial dosing,