Lower demand for Tecfidera, Biogen's drug for multiple sclerosis led to a drop of 22% in the company's share price. Because of the lower demand the 2015 revenue growth for Biogen will be 6-8% instead of 14-16% predicted earlier for the Cambridge, Mass. company. The lower demand is because of a rare side effect, patients discontinuing treatment because it was not helping, and lower reimbursement price in Germany. Tecfidera sales were $2.9 billion in 2014. Another factor is the competition from Gilenya for MS by Novartis.