The US Food and Drug Administration (FDA) is warning that a patient taking fingolimod for multiple sclerosis (MS) developed a rare and life-threatening brain infection.
Progressive multifocal leukoencephalopathy (PML) is a rare condition that leads to severe neurodegeneration and often death. It is caused by the John Cunningham (JC) virus, which is usually harmless but can trigger PML in immunosuppressed individuals.
Previously, the FDA and drug manufacturers have alerted the public to cases of PML among patients taking newer monoclonal antibody drugs, including efalizumab, mycophenolate mofetil, natalizumab, and rituximab, for autoimmune or inflammatory conditions (Kuehn BM. JAMA. 2009;301:1423-1424). The labels of these immunosuppressing drugs have been updated to reflect this risk. But according to the FDA alert, the European patient with PML is the first case in a patient taking fingolimod who had not previously taken natalizumab, a drug also used to treat MS and Crohn disease. Because of its elevated risk of PML, natalizumab is available to US patients only through a restricted distribution program.