A man who was taking Gilenya® and had a history of Tysabri® treatment has been diagnosed with progressive multifocal leukoencephalopathy (PML), a serious brain disease caused by an infection from the JC Virus (JCV). The man, who lives outside the U.S., is now “clinically stable”, according to Gilenya drug maker Novartis.

Novartis said the PML diagnosis was confirmed in mid-March, approximately three and a half months after the man started on Gilenya. He had been off Tysabri for six weeks. Duration of Tysabri treatment had been 3.5 years and he had tested JCV antibody positive.

Presence of the JCV antibodies and longer duration of Tysabri treatment, especially more than two years, have been identified as risk factors for developing PML. A third risk factor is treatment with an immunosuppressant medication prior to starting Tysabri.

Symptoms signaling a relapse began a few weeks after starting on Gilenya, according to Novartis. No MRI was taken then, and the man received high dose steroids for five days with no improvement. When symptoms worsened about two months later, he received a MRI that showed lesions suspicious of PML. Further testing confirmed the PML diagnosis, Novartis said.

“The current assessment is that Tysabri is the drug most likely associated with this case of PML,” Novartis said in a statement. “However, a contribution of Gilenya to the evolution of this case can’t be excluded.”

This is the first known case of PML in a person taking Gilenya, according to Novartis. No change in protocol is anticipated. Gilenya, which is currently the only oral MS drug on the market, has so far been approved in more than 55 countries, with more than 35,000 people receiving treatment.

For more information contact 1-888-Now-Nova (452-0051).

msfocus.org, 16/4/2012