Biogen Idec (NASDAQ:BIIB) is a biotechnology company that makes drugs to treat cancer, neurological diseases, and autoimmune diseases. The company's most important products are Avonex and Rituxan, which treat multiple sclerosis (MS) and non-Hodgkin's lymphomas (NHLs), respectively. The company earned $4.4 billion in revenue and $970 million in net income in 2009.^[1]

Biogen has high hopes for Tysabri, a new multiple sclerosis drug that has the potential to become a major blockbuster. However, Tysabri was withdrawn from the market in 2005 after it was linked to a rare brain disease. After two years of safety reviews, the FDA has reapproved the drug which is currently being relaunched. However, investors still consider Tysabri a significant risk and a make-or-break issue for the company.

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