Aduhelm (aducanumab) became the first anti-amyloid antibody to reach the market, in one of the most contested approvals in FDA history, after decades of failed trials built on the amyloid hypothesis.
Given as a monthly intravenous infusion, it targeted aggregated amyloid beta and held accelerated approval based on plaque reduction alone. That approval proceeded despite a negative advisory committee vote and conflicting results between its two pivotal trials.
Biogen discontinued Aduhelm’s development and commercialization in 2024, citing business priorities rather than safety, and redirected resources to Leqembi. It remains the pivotal case study in accelerated approval controversy, CMS coverage-with-evidence policy, and amyloid-class commercial risk.
