Idraparinux versus standard therapy for venous thromboembolic disease

N Engl J Med. 2007 Sep 13;357(11):1094-104. doi: 10.1056/NEJMoa064247.


Background: Venous thromboembolism is treated with unfractionated heparin or low-molecular-weight heparin, followed by a vitamin K antagonist. We investigated the potential use of idraparinux, a long-acting inhibitor of activated factor X, as a substitute for standard therapy.

Methods: We conducted two randomized, open-label noninferiority trials involving 2904 patients with deep-vein thrombosis and 2215 patients with pulmonary embolism to compare the efficacy and safety of idraparinux versus standard therapy. Patients received either subcutaneous idraparinux (2.5 mg once weekly) or a heparin followed by an adjusted-dose vitamin K antagonist for either 3 or 6 months. The primary efficacy outcome was the 3-month incidence of symptomatic recurrent venous thromboembolism (nonfatal or fatal).

Results: In the study of patients with deep venous thrombosis, the incidence of recurrence at day 92 was 2.9% in the idraparinux group as compared with 3.0% in the standard-therapy group (odds ratio, 0.98; 95% confidence interval [CI], 0.63 to 1.50), a result that satisfied the prespecified noninferiority requirement. At 6 months, the hazard ratio for idraparinux was 1.01. The rates of clinically relevant bleeding at day 92 were 4.5% in the idraparinux group and 7.0% in the standard-therapy group (P=0.004). At 6 months, bleeding rates were similar. In the study of patients with pulmonary embolism, the incidence of recurrence at day 92 was 3.4% in the idraparinux group and 1.6% in the standard-therapy group (odds ratio, 2.14; 95% CI, 1.21 to 3.78), a finding that did not meet the noninferiority requirement.

Conclusions: In patients with deep venous thrombosis, once-weekly subcutaneous idraparinux for 3 or 6 months had an efficacy similar to that of heparin plus a vitamin K antagonist. However, in patients with pulmonary embolism, idraparinux was less efficacious than standard therapy. ( numbers, NCT00067093 [] and NCT00062803 [].).

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anticoagulants / adverse effects
  • Anticoagulants / therapeutic use*
  • Female
  • Follow-Up Studies
  • Hemorrhage / chemically induced
  • Heparin / adverse effects
  • Heparin / therapeutic use
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Oligosaccharides / adverse effects
  • Oligosaccharides / therapeutic use*
  • Pulmonary Embolism / drug therapy*
  • Pulmonary Embolism / mortality
  • Recurrence
  • Treatment Outcome
  • Venous Thrombosis / drug therapy*
  • Venous Thrombosis / mortality
  • Vitamin K / antagonists & inhibitors


  • Anticoagulants
  • Oligosaccharides
  • Vitamin K
  • idraparinux
  • Heparin

Associated data