The global market for multiple sclerosis is currently worth about $12 billion, he said. About 2.5 million people are estimated to have the disease worldwide.

"It looks like BG-12 is the best drug," said Eric Schmidt, an analyst at Cowen and Co, who predicts peak annual sales of about $3 billion. "There are still some things we don't know about its long-term safety, but I think it's possible BG-12 will be the biggest MS treatment in the future."

The link: http://www.reuters.com/article/2011/10/26/biogen-idUSN1E79P05O20111026