FDA Investigates Brain Infection in Patient Taking MS Drug

The U.S. Food and Drug Administration (FDA) is investigating a rare and serious brain infection developed by a patient taking the Novartis multiple sclerosis drug Gilenya (fingolimod).

The patient, in Europe, developed progressive multifocal leukoencephalopathy (PML). The FDA said this was the first reported instance of the infection developing in a Gilenya patient who had not previously received Biogen Idec’s drug Tysabri (natalizumab), Reuters reports. Tysabri, another multiple sclerosis (MS) drug, is associated with a high risk of PML and for this reason, demand for the drug has slowed. PML is potentially fatal.

Novartis informed the FDA of the infection in July but in an email to Reuters the company said the infection was unlikely attributable to Gilenya because the patient had a relatively short exposure to the drug (seven months); the patient had atypical MRI lesions before being treated with the drug; and the patient had repeated exposure to corticosteroids, which can contribute to the development of PML. The company said over 71,000 patients had been treated with Gilenya and “there has been no previous case of PML attributable to Gilenya.”

Gilenya was approved in the United States in September 2010 to treat relapsing forms of MS, a nervous system disease that affects the brain and spinal cord. Tysabri, approved by the FDA in 2004, was briefly withdrawn from market over concerns about PML, according to Reuters.  Because of its effectiveness as an MS treatment, it was reintroduced in 2006 with stricter safety warnings.

PML is caused by the JC (John Cunningham) virus, which is generally harmless, but can lead to an increased chance of PML in people with weakened immune systems.  Tysabri is an immune system-suppressing drug.

The FDA said patients taking Gilenya should not stop taking the drug without discussing this their health care provider.