Doctors say blood-clot drug race too close to call

A half dozen experimental stroke-prevention drugs, and one already on the market, are racing for their share of a market that could be worth $15 billion a year. But doctors say it is still too early to predict how they will stack up in the marketplace.

The upstarts aim to supplant warfarin, a 65-year-old pill that prevents strokes among the estimated 2.2 million Americans with an irregular heartbeat called atrial fibrillation.

Pradaxa, from privately held German drugmaker Boehringer Ingelheim, was approved by U.S. regulators last month, and is therefore the current dominant player. It proved just as effective as warfarin in a large clinical trial but was tested in patients with only moderate risk of stroke.

Xarelto, from Bayer AG and Johnson & Johnson, just missed proving superiority over warfarin in results unveiled on Monday at the annual scientific meeting of the American Heart Association.

But it impressed cardiologists with its ability to sharply lower risk of intracranial bleeding and Hemorrhagic stroke. The pill could be on the market within the next year, if approved by regulators.

“I still haven’t made up my mind, but at the moment the sentiment is probably more toward Pradaxa,” said Ingo Ahrens, an interventional cardiologist at University Hospital in Freiburg, Germany.

“The populations studied were quite different, so we can’t really compare whether one drug is superior to the other,” he said at the heart meeting.

Pradaxa, by being the first to market, could have an enduring market advantage, Ahrens said. Moreover, he likes the fact that the Boehringer Ingelheim drug is given twice daily, saying that ensures strong stroke prevention throughout the day.

But Ioannis Goudevenos, a professor of cardiology at Ioannina University in Greece, said he is leaning toward Xarelto for the convenience of its once-daily dosing.

“I definitely prefer Xarelto,” he said. “It’s just simple logic: do you want to take a drug twice a day if you an take it only once?”

Goudevenos said Xarelto also gets his vote, at least for now, because it was tested in “very high risk patients” and because it was studied in a more rigorous fashion than Pradaxa. “The design was very sophisticated, which gives me confidence.”

“For the very sick, Xarelto appears to be a good alternative to prevent stroke in patients with atrial fibrillation,” said Dr. Stavros Konstantinides, head of the Department of Cardiology at University General Hospital in Alexandroupolis, Greece.

Parthiv Buch, a pharmacologist for the University of Medicine and Dentistry of New Jersey, predicts Pradaxa will be the long-time market leader because it will likely be used among mild- to moderate-risk patients—which represent about 80 percent of the stroke-prevention population.

“But a drug’s success is often determined by its sales force, and that’s where J&J and Bayer will make a big difference for Xarelto,” Buch said.

Similarly, he noted that Pfizer Inc and Bristol-Myers Squibb are conducting large trials of their own contender, called apixaban, which can be expected to get an enormous marketing push from their own formidable sales forces. Apixaban, which is about a year behind Xarelto in clinical trials, has not yet published late-stage stroke prevention data.

Morningstar analyst Damien Conover said Pradaxa, although first to market, could be hobbled by its smaller sales force.

“Boehringer Ingelheim doesn’t have a great track record for huge launches, while Pfizer and Bristol-Myers have entrenched sales forces,” Conover said.

For that reason, he expects apixaban to be the eventual market leader, with Pradaxa and Xarelto following in that order.

Other stroke-prevention treatments loom on the more-distant horizon, including Merck & Co’s betrixaban, which some analysts believe has potential to be the most effective of all, if it succeeds in ongoing mid-stage trials and late-stage studies.

(Editing by Steve Orlofsky)

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By Ransdell Pierson and Debra Sherman

CHICAGO