During a recent Morgan Stanley healthcare conference, Biogen Idec Inc., who along with Elan Corp. co-market the multiple sclerosis (MS) drug Tysabri, said it would be premature to conclude that the risk of developing progressive multifocal leukoencephalopathy (PML) increases the longer patients use the drug.

There has been 13 confirmed cases of PML, a rare and often fatal viral disease that causes progressive damage and inflammation of the white matter of the brain, in patients taking Tysabri–which treats relapsing forms of MS.

As of June 30th, approximately 43,300 patients are actively taking Tysabri. More than 30,000 have taken the drug for more than 1 year and approximately 10,000 have taken it for longer than 2 years.

Tysabri was pulled from the U.S. market in 2005 due to growing concerns over PML cases. It was relaunched in July 2006 with stricter patient safety guidelines.

Although some patients and physicians may express concern over the documented cases of PML, the rate of individuals with MS developing PML after using Tysabri is very low and within the one-in-1,000 patient rate listed on the drug’s label.

Researchers are currently studying a multitude of factors that may play a role in a patient developing PML.

This entry was posted on Tuesday, September 15th, 2009 at 12:26 pm and is filed under All Articles, News Alerts. You can follow any responses to this entry through the RSS 2.0 feed.