Has Biogen Found the Answer to Treating Alzheimer's?

For years, we've seen the failure of clinical trials targeting Alzheimer's disease based on a controversial hypothesis. Biogen's (NASDAQ:BIIB) aducanumab may become the newest addition to the list. Should shareholders be worried about a material decline in the stock price if the U.S. Food and Drug Administration (FDA) rejects the drug's Biological License Application (BLA) filing?