BOSTON — A new, easier-to-use blood-thinning pill offers the first potential alternative in 50 years to warfarin, the standard treatment given to millions of people to prevent blood clots, researchers report today.
The new drug has been tested in 17,000 patients for a number of uses and has been shown to work as well as or, in some cases, better than warfarin at preventing dangerous clots, the researchers said. It reportedly acts more quickly and does not require the frequent blood testing of warfarin, also known as Coumadin.
In today's issue of the New England Journal of Medicine, the researchers report on two of the latest tests of the drug Exanta. The studies showed it reduced the risk of blood clots by one-quarter after knee-replacement surgery and substantially cut the long-term risk of another clot developing in patients who had a clot in a leg or lung.
The drug maker, AstraZeneca, which paid for the studies, has filed for approval of Exanta in Europe and expects to apply for U.S. approval this year.
"I think in most cases it will replace warfarin because it is much easier and seems safer also," said Dr. Sam Schulman, who is at the Karolinska Hospital in Stockholm and led the long-term study of Exanta. "It will take some time, but I think that gradually patients will be switched."
Warfarin, originally developed as a rat poison, was first used as a blood thinner in the 1950s. It is still the only oral blood thinner available to protect against clots that can block blood vessels. It is widely prescribed after strokes, heart attacks and orthopedic surgery and is also given to prevent recurring clots in the legs or lungs.
But warfarin, which takes time to kick in, interacts with other drugs and foods containing vitamin K. It requires regular blood tests to adjust the dose. Doctors are wary of using it for more than a few months because of the risk of bleeding.
Exanta, also known as ximelagatran, works by targeting one coagulation factor; warfarin affects many.
Exanta acts faster and does not have the monitoring or diet drawbacks, the researchers said.
"Everyone has Coumadin patients who aren't doing very well, so they'll probably try this," said Dr. Charles W. Francis, who led the knee-replacement study at the University of Rochester Medical Center in New York. "And if the experience is positive and patients do well, they'll use more and more of it."