Emerging blood thinners to prevent stroke

By Dr. Ananya Mandal, MDNov 15 2010

As blood thinners emerge in the market for stroke prevention many experts believe is still too early to predict how they will stack up in the $15 billion a year market.

The oldest drug is the 65-year-old pill warfarin that prevents strokes among the estimated 2.2 million Americans with an irregular heartbeat called atrial fibrillation. The new ones to fight for the market include:

• Pradaxa (Dabigatran), from privately held German drugmaker Boehringer Ingelheim - approved by U.S. regulators last month. It may be as effective as warfarin in clinical trials but was tested in patients with only moderate risk of stroke. It has a twice daily dosing.
• Xarelto (rivaroxaban), from Bayer AG and Johnson & Johnson has not yet been proved to be superior to warfarin and was revealed at the annual scientific meeting of the American Heart Association this Monday. It sharply lowers risk of intracranial bleeding and hemorrhagic stroke and to some extent heart attacks and is still awaiting approval. One of its advantages is its once daily dosing. Dr. Elaine Hylek, who spoke at a Monday news conference on the findings, although she was not involved with the study said, “In October of 2006, the FDA [U.S. Food and Drug Administration] issued a black-box warning for warfarin due to a growing appreciation of its hazards in routine clinical practice… The requirement for monitoring has relegated millions of people to no therapy or ineffective therapy because of lack of access to monitoring and an intense search for an alternative with more predictable dose responses.” Hylek is an associate professor of medicine at Boston University School of Medicine and reported ties with several pharmaceutical companies.
• Apixaban, from Pfizer Inc and Bristol-Myers Squibb is about a year behind Xarelto in clinical trials, has not yet published late-stage stroke prevention data. Many experts believe apixaban to be the eventual market leader, with Pradaxa and Xarelto following in that order.