Blood Thinner From Pfizer, Bristol-Myers Blocks Leg Clots

Pfizer Inc. and Bristol-Myers Squibb Co.’s experimental drug Eliquis prevented blood clots in the legs and lungs and kept them from recurring, a study found.

Patients who took the medicine were 81 percent less likely to have symptoms of a clot or die than those who got a placebo, according to the study published today in the New England Journal of Medicine. The data is also being presented at the American Society of Hematology meeting in Atlanta.

U.S. regulators in June rejected Eliquis as a treatment to reduce the risk of stroke in people with a type of heart arrhythmia. The New York-based companies are expected to hear by March whether the agency will approve the drug. Should Eliquis gain clearance it may generate sales of $4.18 billion for Bristol-Myers by 2018, according estimates from three analysts compiled by Bloomberg.

“People are really waiting for a new drug that is able to have the same effect as warfarin without monitoring, without the same interaction with food, without the interactions with other drugs,” said Giancarlo Agnelli, a professor of internal medicine at Italy’s University of Perugia who led the study. Pfizer and Bristol-Myers sponsored the research.

Warfarin, a drug used for more than 50 years, requires regular blood tests to ensure the proper dose for patients. Two new competing therapies, Pradaxa, by Boehringer Ingelheim GmbH, and Xarelto, by Johnson & Johnson and Bayer AG, are approved for use against types of deep vein clots.

Attack Lungs

Venous thromboembolisms occur when clots form in blood vessels, which can break off and travel to the lungs. Those pulmonary embolisms kill about 300,000 people a year in the U.S., according to the Cleveland Clinic’s website. Blood thinners such as warfarin can prevent the clots from forming.

Patients with lung clots typically are treated with the fast-acting injected drug enoxaparin. After 5 to 10 days, they begin taking warfarin to prevent future blood clots.

Eliquis, Pradaxa and Xarelto offer a new generation of alternatives in part because they require no monitoring. The new drugs “will take away some of the management of warfarin, which can be time-consuming for a physician,” said John Bartholomew, a physician and director of the Thrombosis Center at the Cleveland Clinic. “There’s definitely a future.”

In the clinical trial, researchers assigned three groups of about 800 patients to receive either a placebo, a 2.5-milligram dose of Eliquis, or a 5-milligram dose of the drug for a year. Of patients getting the placebo, 8.8 percent had a recurrent venous thromboembolism event or died, compared with 1.7 percent taking either dose of the experimental medicine.

Bleeding Effects

Serious bleeding can be a side effect of blood thinners, including hemorrhaging in the brain or stomach bleeding. Of patients taking the placebo, 2.7 percent had a bleeding event, compared with 4.3 percent of patients on the 5-milligram dose of Eliquis and 3.2 percent of patients on the 2.5-milligram dose.

A previous trial of Eliquis showed it to have lower bleeding rates than warfarin.

Agnelli, who ran the trial, said he’d be inclined to prescribe the lower dose, even though the study showed little difference between the two. “As a clinician, I wouldn’t have any doubt, I would go for the lower dose,” he said.

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