Disappointment struck Biogen (BIIB -0.66%) -- one of the best performing big biotech stocks of 2012 -- yesterday after the company announced that its experimental ALS drug failed its phase 3 clinical trial. This is sad news for ALS patients, but multiple sclerosis patients and Biogen investors are now looking toward the potential approval from the Food and Drug Administration for the company's drug BG-12. In this video, our analysts discuss the recent news and also give an overview of Biogen's potential position in the MS drug market.