MS patent challenges put billions in Biogen sales at risk

MS patent challenges put billions in Biogen sales at risk | FiercePharma
Biogen, already in a patent fight over multiple sclerosis star Tecfidera, faces another challenge--this time with fellow MS blockbuster Tysabri. With more than 34% of its sales now at risk, the company may need to revamp its drug portfolio to keep revenue flowing, analysts say.