New findings from a McMaster University-led study of a drug recently identified to prevent stroke in patients with atrial fibrillation have been published in the high-impact New England Journal of Medicine (NEJM) today.
The investigators are now reporting that, in high risk patients who have already had a stroke or warning stroke, apixaban reduces stroke or embolism from 8.3% per year on aspirin to 2.5% per year. This means that one stroke would be prevented, each year, for every 20 of these high risk patients treated with the new drug, apixaban.
The study has found the drug apixaban is superior to aspirin in reducing stroke or embolism in patients with atrial fibrillation who are unsuitable for the traditional therapy of warfarin. It reduces the risk of stroke by more than 50%. Compared to aspirin, apixaban did not significantly increase the risk of major bleeding. Apixaban is a new anticoagulant, still under regulatory review, that blocks the activity of Factor Xa.
"Patients with a stroke who have atrial fibrillation and who cannot take warfarin are at particularly high risk of recurrent stroke," said principal investigator Dr. Stuart Connolly, a professor of medicine at McMaster University and the Population Health Research Institute of McMaster and Hamilton Health Sciences. "It is great to know that we now have a drug that can reduce recurrent strokes substantially in these patients and which most patients will be able to take without the need for monitoring."
The full report published on the NEJM website follows preliminary results of the AVERROES study of apixaban presented last year. The report is also being presented today at the American Stroke Association's international conference in Los Angeles, CA.
Approximately one in four for people aged 40 or older will develop atrial fibrillation (AF), or irregular heart beat, during their lifetime. The biggest threat from AF is a greatly increased risk of stroke, which is five times higher than for others. Blood thinners such as warfarin reduce this risk but are very hard to use successfully. About a third of AF patients are unsuitable for the treatment with warfarin, a vitamin K antagonist, which requires life-long blood monitoring.
The international study, which involved more than 5,500 patients in 522 centres in 36 countries, was funded by pharmaceutical companies Bristol-Myers Squibb and Pfizer Inc.
McMaster University, one of four Canadian universities listed among the Top 100 universities in the world, is renowned for its innovation in both learning and discovery. It has a student population of 23,000, and more than 140,000 alumni in 128 countries.