For 56 years, doctors have literally prescribed a rat poison called warfarin for patients with a serious risk of blood clots.
Now the FDA has approved the first alternative anti-clotting drug, called dabigatran – brand name Pradaxa.
The implications are big – both for 2.3 million North Americans who suffer from a heart-rhythm problem called atrial fibrillation that puts them at risk for blood clots and strokes, and for Boehringer Ingelheim, the new drug's sponsor.
Pradaxa is poised to become a super-blockbuster drug. Analysts say sales could reach $4 billion a year by 2020.
In fact, four other competing drugs are under development. The total market for the new "anti-clotters" could reach $12 billion a year or more. That's why other drug giants, such as Bayer, Johnson & Johnson, Bristol Myers-Squibb and Pfizer are also racing to get into the pool.
Patients and doctors are expected to flock to the new drugs because warfarin (widely known by the brand name Coumadin, among others) is such a difficult drug to take. It interacts with certain foods and other drugs, and different people respond to it very differently. So constant monitoring is necessary to keep blood levels within safe and therapeutic bounds.
"Such monitoring is not necessary for Pradaxa," says Dr. Norman Stockbridge of the FDA. A committee of outside experts unanimously recommended approval on September 20.
Dabigatran/Pradaxa is already approved in Europe for patients after hip and knee replacement surgery.
FDA staffers say studies of the new drug, including one involving more than 18,000 patients, show it reduced the risk of stroke by two-thirds – the same as warfarin.
The major side effect – potentially fatal hemorrhage – doesn't seem to be worse with dabigatran/Pradaxa than with warfarin. But it is a serious risk, so the FDA's approval comes with a condition. Its maker must warn doctors about the risk and address issues such as what to do if patients miss a dose or are taking other anti-clotting drugs.
The FDA staff says more research is needed on how the new drug causes bleeding, and what can be done about it.