Breaking News: The multiple sclerosis drug Tysabri has been linked to an aggressive brain infection known as progressive multifocal leukoencephalopathy (PML). PML attacks the central nervous system and damages the white matter areas of the brain. Tysabri’s label information will be updated to include this new information.
What’s the problem?
April 14, 2011 – This week, the U.S. Food & Drug Administration (FDA) announced that labels of the multiple sclerosis drug Tysabri will be updated to include new information linking the drug to an extremely serious brain infection known as progressive multifocal leukoencephalopathy (PML). To date, PML has killed at least 21 people using Tysabri.
New label changes will include the following information:
- Tysabri side effects may lead to as many as 1.5 multiple sclerosis patients out of every 1,000 contracting PML
- table detailing the PML rate of incidence
- FDA drug safety communication
In 2005, Tysabri was recalled briefly after three MS patients developed PML after using the drug, but was reintroduced a year later with enhanced warnings. Since being reintroduced, at least 102 cases of progressive multifocal leukoencephalopathy infections have been reported in Tysabri users, 21 of those resulting in the death of the patient. FDA has justified keeping Tysabri on the market because it says the drug’s health benefits may outweigh the potential risks.
Progressive Multifocal Leukoencephalopathy (PML)
PML is caused by the reactivation of a common virus in the central nervous system of individuals with compromised immune systems. The condition manifests itself as an infection that causes the loss of white matter (myelin) in multiple areas of the brain. Signs and symptoms of PML include:
- Loss of coordination, clumsiness
- Loss of language ability (aphasia)
- Memory loss
- Vision problems
- Progressive weakness in the legs and arms