* One of at least 8 warfarin replacements being tested
* Market seen being worth more than $10 billion a year
LOS ANGELES Oct 19 (Reuters) - German drugmaker Boehringer Ingelheim won the first U.S. approval for a new stroke-fighting medicine that will compete in an estimated $10 billion market for drugs to replace the 65-year-old blood thinner warfarin.
The Food and Drug Administration cleared Boehringer's drug, Pradaxa, for preventing strokes in patients with a type of irregular heart beat.
The approval gives Boehringer a head start over several other drugmakers, including partners Bayer (BAYGn.DE) and Johnson & Johnson (JNJ.N), and Bristol-Myers Squibb Co (BMY.N) and Pfizer (PFE.N), that are working on competing drugs.
Pradaxa and potential rivals are alternatives to warfarin, a problematic medicine originally developed as rat poison.
Warfarin is the treatment of choice for people at high risk of stroke due to atrial fibrillation, a common form of irregular heart beat. But the drug interacts badly with food and other medicines, carries a high risk of bleeding and requires regular blood tests.
In September, an FDA advisory panel voted 9-0 to recommend approval of Pradaxa, which also carries a risk of serious bleeding.
The warfarin replacement market is expected to be worth more than $10 billion a year and possibly as much as $20 billion. Bayer Chief Executive Werner Wenning recently put the opportunity at $12 billion to $15 billion. [ID:nLDE68E078]
At least eight potential warfarin replacements are currently being tested by major drugmakers. [ID:nLDE67M0DP]
An estimated 2.3 million Americans have atrial fibrillation, and the prevalence is expected to grow to 5.6 million by 2050 as the population ages, Boehringer said.
Boehringer, now controlled by great-grandchildren of the company's founder, suffered a setback in June when U.S. advisers rejected the company's experimental sex pill for women. The company recently halted development of that drug. (Reporting by Lisa Richwine and Deena Beasley; Editing by Steve Orlofsky)