A patient taking Novartis AG’s Gilenya multiple sclerosis pill has been diagnosed with a potentially deadly brain infection. The patient previously took Tysabri, an injection from Weston-based Biogen Idec Inc. and Elan Corp., Novartis said in an e-mailed statement. Tysabri increases the risk of the viral infection, known as progressive multifocal leukoencephalopathy, that usually leads to death or severe disability, according to a warning the drug’s label has carried since 2006.
