Extending Rivaroxaban Prophylaxis Significantly Reduces Risk of Venous Thromboembolic Events: Presented at ASH
By Ed Susman
NEW ORLEANS -- December 7, 2009 -- Patients who receive long-term prophylaxis for venous thromboembolism (VTE) with oral rivaroxaban can reduce their risk of events by more than 80%, compared with placebo, researchers stated here at the American Society of Hematology (ASH) 51st Annual Meeting and Exposition.
“In many cases, after 6 months or 1 year of anti-coagulation treatment to prevent recurrence of thromboembolism, doctors are not sure if they should continue treatment or stop it,” said Harry Buller, MD, Academic Medical Centre, Amsterdam, the Netherlands, during a press briefing here on December 6.
The study indicates that continuing treatment dramatically reduces risk of events such as pulmonary embolism, he added.
“Rivaroxaban decreased the risk of a thrombotic event by 82% compared with placebo,” said Dr. Buller. “We would need to treat 15 patients for 1 year with rivaroxaban to prevent 1 event in this population.”
In the study, 42 patients assigned to placebo experienced VTE compared with 8 patients assigned to rivaroxaban (P < .0001). After the stop of study medication, 6 symptomatic recurrent VTE events occurred in each group during the 1 month observational period
Conversely, because rivaroxaban can cause bleeding, it would take treatment of 139 patients to cause 1 major bleeding episode. Four major bleeds occurred with rivaroxaban compared with none in the placebo group (P = .106). “None of the major bleeds were fatal or occurred in a critical organ,” said Dr. Buller.
“Oral rivaroxaban, 20 mg once-daily, provides clinicians and patients with a simple option if continued anticoagulant treatment is indicated,” he said.
The international, mutlicentre, EINSTEIN Extension (EXT) study was designed to evaluate the long-term benefits of rivaroxaban treatment in the secondary prevention of recurrent symptomatic VTE versus placebo. EINSTEIN is a global clinical development program of 3 trials in about 8,000 patients, of which EINSTEIN-EXT is the third study.
Patients had previously experienced deep vein thrombosis or a pulmonary embolism and had been treated for either 6 or 12 months with rivaroxaban or a vitamin K antagonist such as warfarin. Their physicians had reached a point where they were unsure if they should stop or continue therapy.
Dr. Buller and colleagues randomised these patients (mean age, 58 years; 58% male) to receive placebo (n = 594) or continue treatment with rivaroxaban 20 mg once daily (n = 602) for an additional 6 or 12 months (mean duration, 190 days).
Dr. Buller said that the fixed dose of rivaroxaban did not alter its effect with regard to body mass index or renal status.
Funding for this study was provided by Bayer Healthcare
[Presentation title: Once-Daily Oral Rivaroxaban versus Placebo in the Long-Term Prevention of Recurrent Symptomatic Venous Thromboembolism. the Einstein-Extension Study. Abstract LBA2]
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