What was Aduhelm and why was its approval such a big deal?
A monoclonal antibody approved in June 2021 to clear amyloid plaques — over the objections of its outside advisers — opening a potential multibillion-dollar Alzheimer's market that one expert called the worst FDA decision ever made.
Aduhelm (aducanumab) was a monoclonal antibody given by monthly infusion, designed to clear amyloid-beta plaques from the brain. The FDA granted it accelerated approval on June 7, 2021 on the basis that it reduced amyloid, a surrogate marker, rather than on proof it slowed cognitive decline. With more than six million Americans living with Alzheimer's, the approval promised a new era for patients and a potentially enormous market for Biogen. But it came over the objections of the FDA's outside advisers, who did not believe the data definitively proved benefit, and one expert described it as "the worst decision the FDA has ever made". The drug's short commercial life and eventual discontinuation reflect how contested it was.