Oral rivaroxaban after symptomatic venous thromboembolism: the continued treatment study (EINSTEIN-extension study).

Over recent years, research on anticoagulant drugs has been guided by the requirement for convenient administration and a wide therapeutic window to allow fixed dosing without the need for coagulation monitoring. Rivaroxaban is the first of a new class of anticoagulant drugs, the direct, selective inhibitors of Factor Xa. The EINSTEIN-extension study compared rivaroxaban with placebo in patients who completed their standard treatment course after venous thromboembolism (VTE), in whom there was equipoise with respect to the need for continued anticoagulation. After 6-12 months of treatment, rivaroxaban significantly reduced the risk of recurrent VTE at the cost of a moderate increase in bleeding complications. Overall, these results suggest that rivaroxaban can be a valid alternative to warfarin for patients requiring long-term secondary prevention of VTE. However, additional data are needed for special populations including the elderly, patients with cancer, renally impaired patients and morbidly obese patients, all of whom were scarcely represented in this trial.