Rivaroxaban (Xarelto)
WASHINGTON, DC—Results of the EINSTEIN CHOICE study suggest rivaroxaban is more effective than, and just as safe as, aspirin for long-term anticoagulation in patients with venous thromboembolism (VTE).
In this phase 3 study, patients who had completed 6 to 12 months of anticoagulant therapy were randomized to receive rivaroxaban or aspirin.
Those who received rivaroxaban had a significantly lower risk of recurrent VTE, and the rates of major bleeding were similar between the treatment arms.
“How best to extend anticoagulant use beyond the initial treatment window has been a constant source of debate, with physicians carefully balancing patients’ risk of another VTE with the risk of anticoagulant-related bleeding,” said study investigator Philip S. Wells, MD, of The Ottawa Hospital in Ontario, Canada.
“With EINSTEIN CHOICE, for the first time, we have clinical evidence confirming rivaroxaban is superior to aspirin in reducing recurrent VTE, with no significant impact on safety. These important results have the potential to trigger a paradigm shift in how physicians manage their patients and protect them from VTE recurrence over the long term.”
These results were presented at the American College of Cardiology’s 66th Annual Scientific Session and published in NEJM. The research was funded by Bayer Pharmaceuticals.
The study enrolled 3365 patients with confirmed deep vein thrombosis or pulmonary embolism who were initially treated with anticoagulant therapy for 6 to 12 months.
Patients who required extended anticoagulation at therapeutic doses were not included in this trial, as the objective was to investigate those patients for whom the treating physician was uncertain about the need for continuing anticoagulant therapy.
Patients were randomized in a 1:1:1 ratio to receive a prophylactic dose of rivaroxaban (10 mg once daily), a treatment dose of rivaroxaban (20 mg once daily), or aspirin (100 mg once daily) for up to 12 months. Sixty percent of patients completed the full 12 months of treatment.
Efficacy
Both rivaroxaban doses were superior to aspirin in preventing fatal or non-fatal recurrent VTE, the study’s primary efficacy endpoint.
The rate of recurrent VTE was 1.2% in the 10 mg rivaroxaban arm (hazard ratio [HR]=0.26; 95% CI, 0.14 to 0.47; P<0.001), 1.5% in the 20 mg rivaroxaban arm (HR=0.34; 95% CI, 0.20 to 0.59; P<0.001), and 4.4% in the aspirin arm. Fatal VTE occurred in 0%, 0.2%, and 0.2%, respectively.
For the primary endpoint, the HR for the comparison between the 20 mg and 10 mg rivaroxaban arms was 1.34 (95% CI, 0.65 to 2.75, P=0.42). However, the researchers noted that the comparison of these 2 arms was not powered for significance.
The researchers also found that rivaroxaban reduced patients’ risk of experiencing one of the following events: recurrent VTE, heart attack, ischemic stroke, systemic embolism, or venous thrombosis in another location.
This endpoint occurred in 1.9% of patients in the 10 mg rivaroxaban group (HR=0.33; 95% CI, 0.20 to 0.54; P<0.001), 2.0% of patients in the 20 mg rivaroxaban group (HR=0.35; 95% CI, 0.22 to 0.57; P<0.001), and 5.6% of patients in the aspirin group.
Recurrent VTE or all-cause mortality occurred in 1.3% of patients in the 10 mg rivaroxaban group (HR=0.27; 95% CI, 0.15 to 0.47; P<0.001), 2.1% of patients in the 20 mg rivaroxaban group (HR=0.42; 95% CI, 0.26 to 0.68; P<0.001), and 4.9% of patients in the aspirin group.
Safety
The primary safety endpoint was major bleeding as defined by the International Society on Thrombosis and Haemostasis.
The rate of major bleeding was 0.4% for the 10 mg rivaroxaban group (HR=1.64; 95% CI, 0.39 to 6.84; P=0.50), 0.5% for the 20 mg rivaroxaban group (HR=2.01; 95% CI, 0.50 to 8.04; P=0.32), and 0.3% for the aspirin group.
Rates of clinically relevant non-major bleeding were 2.0%, 2.7%, and 1.8%, respectively (no significant difference).
“We know from previous studies that only about 40% of venous thromboembolism patients are actually on long-term blood thinners,” Dr Wells said.
“We hope that this study, which shows the blood thinner rivaroxaban is as safe as aspirin but much more effective at preventing future clots, will convince patients and their physicians to continue life-long medication that can prevent potentially dangerous blood clots.”
