Biogen laser-focused on Alzheimer's drug as rest of business falters

A single drug has defined Biogen, one of the world's largest biotechnology companies, for the past year and a half.

Known as aducanumab, the drug is far from ordinary. It stands a chance of being the first treatment approved to alter the course of Alzheimer's, a disease that impacts millions of lives and is estimated to cost healthcare systems hundreds of billions of dollars each year. The Food and Drug Administration should decide whether to clear aducanumab for market by June 7, and if it votes yes, investors expect a sales windfall for Biogen.