Idraparinux: review of its clinical efficacy and safety for prevention and treatment of thromboembolic disorders.

Background: Idraparinux is a synthetic pentasaccharide that binds to antithrombin with high affinity. In view of its long half-life, it is suitable for once-a-week administration. Objective: To review the evidence favoring the use of idraparinux for the acute and long-term treatment of patients with venous thromboembolism (VTE) and for the prevention of thromboembolic events in patients with atrial fibrillation (AF). Methods: All preclinical and clinical studies carried out with the use of idraparinux were sought through electronic searches of MEDLINE from January 1, 1999 up to December 31, 2007. Results: The administration of idraparinux in subcutaneous fixed doses of 2.5 mg once weekly was found to be as effective and safe as conventional antithrombotic therapy in the initial treatment of patients with deep vein thrombosis, but less effective than standard therapy in the initial treatment of patients with primary pulmonary embolism. During a 6-month extension of thromboprophylaxis, idraparinux was effective in preventing recurrent VTE but was associated with an increased risk of bleeding versus placebo. Finally, in patients with AF the long-term treatment with idraparinux was as effective as vitamin K antagonists, but caused more bleeding. Conclusions: In its current formulation, idraparinux can be recommended only for the initial treatment of patients with deep vein thrombosis. The bioequipotency of a biotinylated version of idraparinux (idrabiotaparinux), whose effects can be reversed by a neutralizing agent (avidin), is under investigation in the treatment of VTE at present, as is the use of lower doses in patients with AF.