By granting accelerated approval for Biogen Inc.’s Aduhelm (aducanumab) for Alzheimer’s disease (AD), the FDA is “essentially confirming that the beta-amyloid hypothesis has been validated,” Mizuho analyst Salim Syed said in an alert to investors. Shares of Cambridge, Mass.-based Biogen (NASDAQ:BIIB) closed $395.85, up $109.71, or 38.3%, as Wall Street hailed the first new AD therapy to reach the market since 2003.