By | February 06 2013 9:08 AM

Biogen Idec Inc. (NASDAQ:BIIB) has agreed to make an upfront payment of $3.2 billion and later pay royalties to acquire sole ownership of the multiple sclerosis drug Tysabri from its Irish partner Elan Corp. PLC (NYSE:ELN), which owns 50 percent of the world's second-biggest MS drug.