The U.S. Food and Drug Administration said it will update the label of Novartis AG’s multiple sclerosis drug, Gilenya, after cases of serious brain infections were linked with its use.

A case of definite progressive multifocal leukoencephalopathy (PML) and a case of probable PML have been reported with the use of the drug, a first in patients not previously treated with an immunosuppressant for MS or any other condition, the agency said on Tuesday.

As a result, information about these cases is being added to the oral drug’s label, the FDA said. (

PML has long been a concern associated with the long-term use of MS drugs. Sales of Biogen Inc’s Tecfidera and Tysabri had been affected by reports of the rare brain infection.

Caused by a common virus that is harmless for most, PML tends to trouble patients with weakened immune systems, including those taking immunosuppressants.

The infection causes symptoms such as vision problems, confusion, as well as changes in personality, memory and orientation — potentially culminating in severe disability or death.

Gilenya was approved in 2010 to reduce relapses and delay disability progression in patients with relapsing forms of MS. (

The drug raked in sales of about $700 million in the Swiss drugmaker’s latest quarter. (

The FDA had said in August 2013 that it was investigating a case of PML in a patient taking Gilenya, but could not conclusively link the infection to the drug as the patient had been treated with other drugs as well.

More than 2.3 million people are affected by MS, a chronic, unpredictable incurable disease of the central nervous system, according to the National Multiple Sclerosis Society.


(Reporting by Natalie Grover in Bengaluru; Editing by Sriraj Kalluvila)

Source: Reuters