AVERROES: Apixaban in Atrial Fibrillation Study Stopped Early for Benefit

June 14, 2010

June 14, 2010 (Princeton, New Jersey and New York, New York) The Apixaban versus Acetylsalicylic Acid to Prevent Strokes (AVERROES) trial, a study comparing the safety and effectiveness of apixaban (Pfizer/Bristol-Myers Squibb) and aspirin in patients with atrial fibrillation, has been stopped early after a predefined interim analysis by the independent data monitoring committee "revealed clear evidence of a clinically important reduction in stroke and systemic embolism" [1].

Full data from the study are not yet available, although a company statement issued yesterday reported that the interim analysis demonstrated an acceptable safety profile for apixaban compared with aspirin.

The AVERROES trial is being coordinated by the research institute at McMaster University, in Hamilton, ON, and consisted of 5600 patients from 36 countries with all types of atrial fibrillation who were intolerant of or unsuitable for warfarin. The study began in September 2007, with patients randomized to 5 mg of apixaban or 81 to 324 mg of aspirin for up to 36 months or until the end of the study.

The primary efficacy outcome is the time from the first dose of the study drug to the first occurrence of ischemic stroke, hemorrhagic stroke, or systemic embolism. The secondary efficacy outcome includes the time to the first occurrence of ischemic stroke, hemorrhagic stroke, systemic embolism, MI, or vascular death.

Apixaban is an oral factor Xa inhibitor that is being tested in a number of different types of patients. In one phase 2 study, reported by heartwire , researchers showed that apixaban added to antiplatelet therapy in acute coronary syndrome patients resulted in a dose-dependent increase in bleeding and a trend toward a reduction in clinically relevant ischemic events. Another study, also reported by heartwire , showed that the drug missed its primary end point in patients undergoing knee surgery, failing to meet statistical criteria for noninferiority when compared with enoxaparin (Lovenox, Sanofi-Aventis) for the prevention of venous thromboembolism.

Full results from the AVERROES study will be published at a later date in a medical journal and will likely be presented at a future cardiology meeting, according to company officials.


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