NEW ORAL ANTICOAGULANTS SHOW PROMISE IN PHASE 3 STUDIES

Studies of 2 new oral anticoagulants, rivaroxaban and dabigatran,in joint replacement patients have yielded positiveresults for prevention of venous thromboembolism (VTE).Results of the studies were recently presented at the 2007Congress of the International Society on Thrombosis andHemostasis. Results obtained with rivaroxaban suggestedsuperior efficacy and similar bleeding rates when comparedwith enoxaparin. Two studies were presented for dabigatran,the results of which were conflicting. In the RE-NOVATE trial,dabigatran showed equivalence to 40 mg of enoxaparin,while in the RE-MOBILIZE study it failed to show equivalenceto a 60-mg dose of enoxaparin.

The 2 new oral anticoagulants are among a number ofcompounds under development that may one day replacewarfarin. Neither of the drugs needs regular monitoring.Liver-toxicity problems, which caused a predecessor drug(ximelagatran) to be rejected by the FDA, have not beennoted. Dabigatran appears closest to market, having alreadybeen filed for approval in Europe. Approval applications forprevention of VTE are expected to be filed for rivaroxaban inthe United States in 2008. Both drugs are also under study foruse in atrial fibrillation and acute coronary syndromes.