Sanofi-Aventis says that taking its blood thinner Lovenox for five weeks prevents more clots than using the medicine for the standard 10 days of treatment.

The company presented data at the XXI International Society on Thrombosis and Haemostasis Congress in Geneva, Switzerland from the EXCLAIM study, which showed the benefit of extended prophylaxis in acutely ill patients with reduced mobility by demonstrating the superiority of five weeks course of prophylaxis with Lovenox (enoxaparin) compared to 10 days regimen with a statistically significant 44% reduction in venous thromboembolism (VTE) events.

The Franco-German drugmaker noted that acutely ill patients are at high risk of VTE and the benefit of thromboprophylaxis with enoxaparin is already considered as the standard regimen. Nonetheless, this study is important because clinical practice suggests that the risk of VTE may continue beyond 10 days, particularly in patients with reduced mobility, and the efficacy and safety of extended prophylaxis “had never been assessed”.

The 44% relative risk reduction in VTE events observed for extended-duration prophylaxis with enoxaparin versus placebo was associated with a reduction in symptomatic VTE by 73% and asymptomatic proximal DVT by 34%. The company added that no statistically significant differences were observed for symptomatic pulmonary embolism or fatal PE.

Victor Tapson at Duke University Medical Center in the USA, and a lead investigator of the EXCLAIM study, said that "what the trial results showed is that patients do not leave their risk for VTE at the door when they leave the hospital”, while Russell Hull from the University of Calgary, Canada and chair of the steering committee for the study, claimed that "similarly to the initial demonstration of the benefit of thromboprophylaxis for acutely ill medical patients, first established by the MEDENOX trial, EXCLAIM “should be a landmark trial in advancing the standard of care of patients at high risk".

The data will help Sanofi expand the use of Lovenox, its best-selling drug which brought in 614 million euros in the first quarter, up 12%, though its future looks decidedly dicey after a California court invalidated the patent on the drug in February. The drug is particularly important now following the firm’s withdrawal of an application for US Food and Drug Administration approval for the anti-obesity drug Acomplia (rimonabant) after an expert panel voted against recommending it.