The findings are reported in the February 9 issue of the Journal of the American Medical Association.
In patients with atrial fibrillation, the upper part of the heart often quivers instead of beating, so blood pools and clots in the upper chambers. The blood clots tend to be large and can travel to the brain causing massive strokes.
AstraZeneca, the company that developed Exanta, had submitted a New Drug Application to the Food and Drug Administration for approval of the drug as an agent to prevent strokes in patients with atrial fibrillation as well as to prevent blood clots in other conditions. The drug was intended as an alternative to warfarin.
In October 2004, the FDA denied Exanta approval. The agency noted that Exanta carried a small risk of liver damage and cited insufficient evidence that it was as effective as warfarin for preventing strokes.
"Warfarin is extremely effective," says lead author Brian F. Gage, M.D., associate professor of medicine. "It lowers the risk of stroke by 65 percent. Unfortunately, patients have different sensitivities to warfarin, so it's difficult to adjust the dose, especially when initiating the drug. While they're on warfarin, patients' blood clotting has to be monitored often, and patients find that inconvenient. Warfarin also interacts with various foods and other drugs. Moreover, it doubles the risk of hemorrhage."
Before Exanta, the alternative for patients unable to tolerate warfar
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Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University School of Medicine
8-Feb-2005