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Studies show misuse of expensive blood-clotting drug

Two studies from the School of Medicine, published Monday in Annals of Internal Medicine, revealed that an expensive blood-clotting drug intended only for hemophilia patients has been mainly prescribed for patients without this disorder. This practice, however, may pose certain health risks.

The first study looked at uses of the drug, known as recombinant factor 7a (RF7a), at American hospitals. RF7a, approved by the U.S. Food and Drug Administration (FDA) in 1999, was developed for a small group of hemophilia patients whose bodies reject other treatments to curtail bleeding.

Veronica Yank, an instructor in medicine and the first author of one of the studies, said researchers were surprised to find that the drug was prescribed off-label. More than 17,000 patients without hemophilia received the drug in 2008 to prevent or stop heavy bleeding.

Off-label prescribing is a common practice where doctors use a drug to treat conditions other than those approved by the FDA. The practice is not illegal, but Yank said many patients and doctors fail to understand that drugs do not have the same level of scrutiny for off-label uses as they have for on-label uses.

The study estimates that the drug was only used to treat hemophilia patients in 4 percent of cases in U.S. hospitals from 2000 to 2008. A staggering 96 percent of RF7a usage involved cases of heart surgery, trauma, intracranial hemorrhages (bleeding in or near the brain) and a host of other problems.

Previously published studies raised concerns that RF7a increased the risk of blood clots, spurring the U.S. Agency for Healthcare Research and Quality (AHRQ) to ask researchers to examine the drug in 2008. The agency funded both Stanford studies.

The second study examined the risks and benefits of prescribing RF7a for five particular patient scenarios or conditions: heart surgery, intracranial hemorrhage, body and brain trauma, liver transplantation and prostate surgery.

“We found no evidence to suggest that this particular drug saves lives for any of the scenarios that we evaluated,” Yank said.

They also found evidence that use of the drug in these conditions significantly increased the risk of blood clots, particularly for cardiac surgery and bleeding in or around the brain. These clots can lead to heart attacks or strokes near the clot.

“A way to translate that risk to readers is the example of heart surgery,” Yank said. “The risk of clots is increased by 5 percent with the use of this drug. That means if 20 patients are given the drug, one would be expected to suffer a blood clot that would not have otherwise occurred.”

The drug is also very expensive, ringing in at an estimated $10,000 per dose.

The authors say RF7a is a good example of what happens when doctors increasingly use a “wonder” drug for uses distinctly different than its original purpose.

“We want doctors and hospitals to be having serious conversations about whether this drug should be prescribed for these indications,” Yank said.

The other Stanford co-authors of the first study include Randall Stafford, associate professor of medicine at the Stanford Prevention Research Center; Dena Bravata M.S. ‘00, an adjunct associate of the Center for Health Policy/Center for Primary Care and Outcomes Research; Kristan Staudenmayer M.S. ‘10, assistant professor of surgery; graduate student Robin Eisenhut; Vandana Sundaram, assistant director for research at CHP/PCOR; Ingram Olkin, professor emeritus of statistics and of education; Kathryn McDonald, executive director of CHP/PCOR and Professor of Medicine Douglas Owens, a senior investigator at the Veterans Affairs Palo Alto Health Care System.

About Billy Gallagher

Billy Gallagher is a senior staff writer at The Stanford Daily. He has previously worked at The Daily as editor in chief, a managing editor of news, news desk editor, sports desk editor and staff development editor. He is a junior from Villanova, PA majoring in Economics. He is also a writer for TechCrunch.