In this video, health-care analyst David Williamson discusses Biogen's latest drug up for FDA approval. The big biotech is on a roll lately: The FDA recently accepted applications for two hemophelia drugs and today came news of multiple sclerosis drug Plegridy. This is a longer-lasting, and therefore less-injected, version of the company's flagship product Avonex.

Watch and find out why this submission is important for expanding Avonex's sales and why it may help protect the franchise from its biggest threat, another recently approved Biogen MS drug.