'However, in response to the decision, three members of the Food and Drug Administration’s expert independent advisory committee, which voted almost unanimously against approval, resigned, with Harvard professor of medicine Aaron Kesselheim describing it as “probably the worst drug approval decision in recent US history.”1 Given that existing treatments for Alzheimer’s disease have only marginal benefit at best,2 what does aducanumab’s controversial approval in the US mean for patients, clinicians, and researchers?'