Biotech company Celgene Corp. this week sent a letter to doctors warning that a study of its drug to treat dangerous blood clots suggests it may increase the risk of death in elderly patients.
The letter, posted late Wednesday on the Web site of the Food and Drug Administration, recommends that doctors consider alternatives to Innohep in patients with deep vein thrombosis, life-threatening blood clots in major veins such as in the legs.
The new warning comes after analysis of preliminary data from a study in Europe of patients 70 years old and older — a group often excluded from medical studies — who were diagnosed with deep vein thrombosis and also had failing kidneys.
The study, known by the acronym IRIS, was stopped in February 2008 after 350 of the patients had been followed for three months. By then, 13 percent in the group getting Innohep had died of various causes, versus 5 percent in a comparison group getting heparin, a widely used anticlotting drug.
"There is no clear pattern as to the causes of death," the FDA said in a statement.
The agency said available data cannot rule out the possibility that patients in the Innohep group suffered another deep vein blood clot or that there was a problem in manufacturing of the drug.
Celgene, based in Summit, N.J., one of the country's biggest biotech companies, sells Innohep, but it is manufactured by Leo Pharmaceutical Products of Denmark, according to the product's package insert.
Innohep has been sold in Europe since 1991 and was approved for U.S. sales in 2000. From early 2001 through early 2007, more than 30 million people in 60 countries were treated with the drug, which is injected just under the skin.
The FDA said it had received 383 reports of side effects and complications worldwide, including 96 deaths, as of Oct. 15, 2008.
Late last July, Celgene sent another letter to doctors warning of an elevated risk of death in patients aged 90 and older. The new letter extends the warning to all elderly patients.
The FDA statement Wednesday said the agency has asked the company to revise the package insert, or label, "to better describe the overall study results which suggest that, when compared to (heparin), Innohep increases the risk of death for elderly patients" with failing kidneys.
The agency said it expects to get a final report from the study in January and will complete its review soon after that.