Multiple Sclerosis and Crohn’s Disease Drug Tysabri Linked to Rare, Deadly Brain Infection

Tysabri, a drug prescribed to tens of thousands of multiple sclerosis patients and also used to a lesser extent to treat the form of irritable bowel syndrome called Crohn’s disease, has been linked to more than a dozen cases of a potentially deadly opportunistic infection of the brain.


Progressive multifocal leukoencephalopathy (PML) is a viral brain infection that has been reported in at least 13 Tysabri patients since 2006 when marketing of the drug resumed, according to the Food and Drug Administration. Tysabri was approved by the Food and Drug Administration in November 2004, but was quickly removed from the market after some users developed PML. The drug was later allowed back on the market after stronger warning labels about the risks of PML were added to Tysabri’s labeling.

Tysabri is approved to treat relapsing forms of multiple sclerosis and moderate to severe cases of Crohn’s disease. However, less than two percent of Tysabri use in the United States is for Crohn’s disease and the vast majority of patients taking the drug are being treated for multiple sclerosis.

Also, no cases of PML have been reported in patients taking the drug for Crohn’s disease. All of the infections have been reported in multiple sclerosis patients taking Tysabri.

The use of Tysabri also has been found to cause liver toxicity and malignant melanoma in some users. The problems developed shortly after the drug was administered.

By most estimates, more than 43,000 patients around the world are currently taking Tysabri, including more than 30,000 who have been taking the drug for more than a year and another 10,000 who have been on it for more than three years. The drug is made by Biogen Idec Inc.

Drug safety officials have taken repeated actions against Tysabri to warn users and prescribing physicians about the risks of injury from the drug.

In April 2009, federal regulators warned Biogen about Internet advertisements for Tysabri the FDA said falsely promoted the drug without emphasizing the risks of PML and other serious health complications.

Then, in September 2009, a new study concluded that Tysabri put patients at greater risk of developing PML by awakening the virus that causes the disease and making the virus even stronger.

This article is a reprint of http://www.attorneyatlaw.com/2009/09/multiple-sclerosis-and-crohns-disease-drug-tysabri-linked-to-rare-deadly-brain-infection/ The time or date displayed reflects when an article was added to Google News. Sep 18, 2009‎