Biogen, Elan report Tysabri brain disease cases

LOS ANGELES (Reuters) - Biogen Idec Inc (BIIB.O) and Elan Corp Plc (ELN.I) said on Thursday they have notified regulators of two confirmed cases of a potentially deadly brain disease in multiple sclerosis (MS) patients being treated with Tysabri.

Sales of the drug were suspended in 2005 after three cases of the brain infection, progressive multifocal leukoencephalopathy (PML), developed.

Tysabri returned to the market in 2006 with limits after the Food and Drug Administration decided MS patients were willing to accept the risks given the potential benefits.

(Reporting by Deena Beasley; editing by Jeffrey Benkoe)