A promising new drug shown to be better than warfarin at preventing strokes in patients with a dangerously irregular heartbeat may reach the U.S. market more quickly after health regulators gave it an expedited review.

Eliquis, from Bristol-Myers Squibb Co and Pfizer Inc, would be the third new U.S. treatment for these patients after Xarelto, from Bayer and Johnson & Johnson, was approved earlier this month, and Pradaxa from Boehringer Ingelheim was approved last year.

The U.S. Food and Drug Administration typically takes 10 months or longer to review new drug applications but will give Eliquis a quicker review after clinical trials showed the drug was safer and more effective than decades-old warfarin.

The FDA is expected to give a decision on approval by March 28, Bristol and Pfizer said. That would close the gap in the three-way race, as the new treatments compete in an estimated $10 billion market.

Many industry watchers had expected Xarelto to have a full year on the market before facing competition from Eliquis. But some analysts told Reuters earlier this month that the FDA had a good case for accelerating its review of Eliquis.

"With two alternatives to warfarin currently approved and one on the near horizon, it seems like a dream come true for patients and physicians who have lived with warfarin for the last 40 years," said Dr. Micah Eimer, a cardiologist in private practice in suburban Chicago. Eimer, an assistant professor at the University of Chicago Pritzker School of Medicine, has no financial affiliation with any of the three drugs' manufacturers.

Atrial fibrillation affects more than 2 million Americans. The condition causes blood to pool in the heart and form clots, raising the risk of stroke.

Many patients are unwilling or unable to take warfarin because of dietary requirements, bleeding risk, conflicts with other medicines and the need for regular testing to ensure the right concentrations of warfarin are in the bloodstream.

ISI Group analyst Mark Schoenebaum said he expects Eliquis to become the dominant player in the atrial fibrillation market.

Anthony Butler, an analyst with Barclays, said Eliquis remains his pick for the top selling oral anticoagulant in the next decade.

Deutsche Bank analyst Barbara Ryan said peak sales of Eliquis could top $2.5 billion.

"Our estimates could prove conservative depending on the degree to which warfarin is displaced and the likelihood that Eliquis will hold the No. 1 (market) share position," Ryan wrote in a research note.

Bristol-Myers shares rose 1.1 percent, performing better than a slight increase for the wider stock market. Pfizer gained 1.0 percent. Bayer gained 0.4 percent in Frankfurt.

Eimer wouldn't rate the chances of each of the three drugs to succeed but did see Pradaxa having an advantage as being first to market.

"Physicians (may) develop an initial comfort level with the drug and are unlikely to want to develop that again with another drug for the same clinical indication," he said.At the same time, Eimer does not necessarily see a huge migration of patients who are tolerating warfarin well.

He noted there is little safety data with the new drugs on big groups of patients, including the elderly, people with impaired kidney function and patients with significant valvular heart disease.

"I am expecting and dreading the day a patient of mine on a newer agent presents with significant bleeding or trauma and we are not certain how to reverse the blood thinning effect the way we can with warfarin," Eimer said.