Can lowering tau biology translate into a clinically meaningful slowing of decline in people with early symptomatic Alzheimer’s disease? That is the practical question behind BIIB080, an intrathecal antisense therapy designed to reduce production of tau protein by targeting the tau gene transcript. In a phase 1b program originally designed for safety and dosing, investigators later examined cognitive, functional, and global outcomes as exploratory endpoints. The clinical question matters because current disease-modifying options primarily target amyloid, while tau pathology tracks...