Two phase III failures with Roche Holding AG subsidiary Genentech Inc.’s gantenerumab in staving off mild cognitive impairment tied to Alzheimer’s disease (AD) revealed the level of amyloid-beta removal was lower than the company expected. The protein amyloid beta accumulates in the brains of AD patients and its removal is suspected to be an eventual boon to AD patients. But there are still plenty of doubts. Top-line results from Genentech’s phase III Graduate I and II studies show gantenerumab, a fully human monoclonal IgG1 antibody, missed the primary endpoints of slowing clinical decline in those with mild cognitive impairment due to AD and mild AD dementia.