Hemophilia Drug Can Damage Heart, Study Finds

* Doctors give NovoSeven to stop other serious bleeding

* 35 studies weighed in new analysis

* Danger most pronounced in older patients

By Gene Emery

BOSTON (Reuters) - Using high doses of Novo Nordisk's anti-clotting medicine to treat dangerous bleeding in non-hemophiliacs may raise the risk of heart attack or related complications, researchers said Wednesday.

The drug, NovoSeven, is a genetically engineered version of factor VII, a key protein missing in some people with the bleeding disease hemophilia.

Some doctors prescribe the drug in "off-label" use to stop unwanted bleeding associated with stroke, trauma, surgery, transplantation and other medical conditions. Doctors may prescribe any approved drug for any reason they want to.

But this drug may not be worth the risk, said Dr. Marcel Levi of the University of Amsterdam and colleagues at Novo Nordisk.

Their analysis of 35 studies found that the overall likelihood that an artery would clog was 68 percent higher with NovoSeven therapy compared to a placebo.

The risk of heart attack, angina or related complication more than doubled, the researchers reported in the New England Journal of Medicine .

People over 65 who got the drug were more than twice as likely to develop an unwanted clot in an artery than younger patients, they found. Those over 74 were three times more likely.

"This is a highly effective drug in patients with excessive blood loss in various circumstances. But the main message is you need to realize that there is a price to be paid," Levi said in a telephone interview.

"If a patient's bleeding so serious he or she may have a major problem or even die, you can accept the small increased risk of having an arterial thrombosis (clot)," Levi said.

"On the other hand, if it's not excessive bleeding and there are other options to explore, the safety issue may hold you back from doing this."

The treatment did not increase the risk of unwanted clots in veins, regardless of age, the researchers found. It increased the risk of stroke, but not enough to be statistically significant.

Dr. Louis Aledort of the Mount Sinai School of Medicine in New York said in a commentary that 4 percent of the NovoSeven used at his hospital is for non-approved therapy. "At other centers, the rate of off-label use may be even higher," Aledort said.

Levi said hospitals that are quick to give the drug may now want to reconsider that practice. (Editing by Philip Barbara)