BASEL, Switzerland – Novartis said Friday a patient treated with its multiple sclerosis (MS) pill Gilenya was diagnosed with a rare and often fatal brain disease.
"The current assessment is that Tysabri is the drug most likely associated with this case of PML. However, a contribution of Gilenya to the evolution of this case can't be excluded."
The Swiss drugmaker said the patient, whose identity was not disclosed, previously was treated with another MS drug, Tysabri, co-marketed by Biogen Idec and Elan, which already was associated with progressive multifocal leukoencephalopathy (PML).
"The current assessment is that Tysabri is the drug most likely associated with this case of PML," Novartis said. "However, a contribution of Gilenya to the evolution of this case can't be excluded."
The development comes at a critical time for Novartis' Gilenya, whose safety profile recently came into question after the death of one person in the US last fall within 24 hours of starting treatment. Heart problems in some patients also were reported.
The European Medicines Agency, the body responsible for licensing Gilenya in Europe a year ago, is expected to issue a decision on the safety of the medicine April 20 following an in-depth review.
Novartis said it does not know of any confirmed PML cases in patients treated with Gilenya, also known as fingolimod, who were not previously been treated with Tysabri. The company said details on the case were being submitted to the health authorities.
Elan spokeswoman Niamh Lyons said, "At this stage, we can't comment on the role that either drug might have had in this PML case." Biogen was not immediately available to comment.
"The development has to be taken seriously, but the question is more whether this is a trend, with a second or even third case coming up in the next few weeks," according to analyst Andrew Weiss, with Vontobel in Zurich.
Gilenya, which is currently the only oral MS treatment on the market, so far has been approved in more than 55 countries, with more than 25,000 patients having been prescribed it.
Industry analysts have said it could generate sales of at least $1 billion a year, helping to offset lost revenue caused by the expiry of Novartis' top-selling heart drug, Diovan.
Europe's drug regulator in January launched an in-depth review of the drug's benefits and risks and recommended that doctors closely monitor the hearts of patients after they have been given the first dose of the drug. The final verdict is likely to have a big impact on the product's prospects and investor sentiment to Novartis shares.