Bristol-Myers Squibb Company (BMS) and Pfizer announced that the companies have agreed to stop the phase 3 AVERROES clinical trial of apixaban in patients with atrial fibrillation. The study will be stopped early because a predefined interim analysis by the independent Data Monitoring Committee (DMC) revealed clear evidence of a clinically important reduction in stroke and systemic embolism in patients with atrial fibrillation considered intolerant of or unsuitable for vitamin K antagonist therapy who received apixaban as compared to aspirin. This interim analysis also demonstrated an acceptable safety profile for apixaban compared to aspirin.

The AVERROES (Apixaban Versus Acetylsalicylic Acid to Prevent Strokes) study included 5,600 patients with atrial fibrillation at risk for stroke who were considered intolerant of or unsuitable for therapy with a vitamin K antagonist such as warfarin. Patients were randomized to receive either apixaban 5mg twice daily or aspirin 81mg to 324 mg once daily. Conducted in 36 countries, the study was coordinated by the Population Health Research Institute (PHRI) at McMaster University and at Hamilton Health Sciences.

The AVERROES investigators have been informed of the decision to stop the study. Bristol-Myers Squibb and Pfizer are working to close out the study and to ensure that patients are informed of the opportunity to start treatment with apixaban in an open label extension. PHRI will complete a full evaluation of the final AVERROES data set and will seek to publish the results in a peer reviewed journal and present the findings at a scientific congress once the full analysis is complete.

Apixaban, which is currently being developed by Bristol-Myers Squibb and Pfizer, is an investigational oral factor Xa inhibitor, a new class of agents being studied for the prevention and treatment of blood clots. Apixaban is being investigated within the EXPANSE Clinical Trials Program, which is projected to include nearly 60,000 patients worldwide across multiple indications and patient populations and includes a total of nine completed or ongoing, randomized, double-blind Phase 3 trials, including AVERROES.

The apixaban phase 3 trial program is evaluating the prevention of venous thromboembolism, prevention of stroke and other thromboembolic events in patients with atrial fibrillation, the treatment of venous thromboembolism and secondary prevention of cardiovascular events in patients with acute coronary syndrome.

In 2007, Pfizer and Bristol-Myers Squibb entered into a worldwide collaboration to develop and commercialize apixaban, an investigational oral anticoagulant discovered by Bristol-Myers Squibb. This global alliance combines Bristol-Myers Squibb's long-standing strengths in cardiovascular drug development and commercialization with Pfizer’s global scale and expertise in this field to maximize the potential benefits of apixaban for patients.