Once-weekly anticoagulant eased treatment burden for patients with DVT

Patients taking idraparinux had a 2.9% recurrence rate compared with those on low–molecular-weight heparin who had a 3% recurrence.

Issue: January 1, 2007

ASH 48th Annual Meeting ORLANDO, Fla — Subcutaneous idraparinux taken once weekly is as safe and effective as the more complicated standard treatment of heparins and vitamin K antagonists, according to a recent study presented here at the 48th Annual Meeting of the American Society of Hematology.

This new drug for treating deep vein thrombosis can be taken less often than the standard treatment, which could ease the burden faced by some patients.

“In the past decade, the introduction of low–molecular-weight heparin was a major breakthrough in the treatment of venous blood clots, paving the way for outpatient treatment. Now, idraparinux has the potential to further advance the treatment of this common and potentially deadly condition,” said ASH President Kanti R. Rai, MD, from Long Island Jewish Medical Center and the Albert Einstein College of Medicine in New York.

The limitations of current therapies are the need for daily injections, adverse interactions with food and many other drugs, and a wide variation in treatment results that requires intensive monitoring.

More than 5,000 patients, 2,904 with DVT and 2,215 with pulmonary embolism, participated in the study comparing standard treatment with idraparinux (Sanofi-Aventis). The researchers treated patients with either 2.5 mg of idraparinux by subcutaneous injection once a week or the standard daily treatment regimen of low–molecular-weight heparin followed by a vitamin K inhibitor for three to six months. The primary measure of success was whether a symptomatic venous clot would recur three months after treatment.

The researchers found that in the DVT group, idraparinux was just as effective as the low–molecular-weight heparin regimen, with a recurrent incidence of 2.9% in the patients taking idraparinux, compared with 3% in the control group (95% CI, 0.63-1.50). Severe bleeding occurred in 4.5% of the patients with DVT taking idraparinux and in 7% of those receiving traditional treatment (P<.01). By six months, the bleeding rates were similar.

Among the patients with pulmonary embolism, the new drug was not as effective as the standard treatment. The incidence of recurrent blood clots after three months was higher in those taking idraparinux at 3.4%, compared with 1.6% in the control group.

“Although the results for idraparinux in the pulmonary embolism group were surprising and disappointing, for patients with deep vein thrombosis our findings should have a remarkable impact,” said Harry Buller, MD, chairman of the department of vascular medicine at the Academic Medical Center in Amsterdam, the Netherlands. “The fact that once-a-week injections of idraparinux are just as effective and safe as traditional treatment frees patients with DVT from the daily injections and continuous monitoring that would otherwise be required.”

Editor’s note: This was an interesting and potentially important presentation. Like its “sister” drug fondaparinux (Arixtra, GlaxoSmithKline), it is synthetic and has advantages over heparin and low molecular weight heparins. Its most unique feature is that it is given once weekly. But it still needs to be administered via injection. One of the problems with this class of synthetic carbohydrates is that, with the development of bleeding, there are no direct ways to neutralize the drug. And with a long half-life, the advantage of idraparinux, reversing bleeding complications are also compounded. – Bruce Furie, MD

For more information:
Buller HR on behalf of the Van Gogh Investigators. Evaluation of once weekly subcutaneous idraparinux versus standard therapy with heparin and vitamin K antagonists in the treatment of deep-vein thrombosis or pulmonary embolism — the Van Gogh Investigators. Abstract 6. Presented at: 48th Annual Meeting of the American Society of Hematology; Dec. 9-12, 2006; Orlando, Fla.