August 29, 2013 — Gilenya, a medication for multiple sclerosis (MS), has been linked to one case of a rare but serious brain infection called progressive multifocal leukoencepalopathy (PML).
According to the FDA:
“Patients should not stop taking Gilenya without first discussing any questions or concerns with their health care professionals. We are providing this alert while we continue to investigate the PML case.”
Novartis reported that the patient was treated with Gilenya for nearly eight months. Before using Gilenya, the patient took other medications, but not Tysabri (natalizumab), which is another MS drug that has been linked to PML. The patient was diagnosed based upon symptoms and discovery of the JC virus DNA in their cerebrospinal fluid.
This is the first case of PML associated with Gilenya. Novartis has reported that 71,000 people have used Gilenya to treat MS since it was approved in 2010.
What is PML?
Progressive Multifocal Leukoencephalopathy (PML) is a rare but serious brain infection that is caused by the John Cunningham (JC) virus. Although infection with the JC virus is widespread, it usually only causes PML in people with weak immune systems. Drugs that weaken a person’s immune system, such as Gilenya, may also increase the risk of PML.
PML damages myelin, which is a fatty covering around nerves in the brain and spinal cord that insulates electrical signals. Damage to myelin can cause electrical signals to slow down.