The landmark, yet controversial, accelerated approval of Biogen and Eisai’s anti-amyloid antibody Aduhelm came despite Phase III clinical trial data resulting in one positive and one negative study. In its release of this groundbreaking news, the US Food and Drug Administration (FDA) acknowledged there is some uncertainty around the data, but reiterated that the treatment is the first to show a benefit in amyloid plaque reduction, thus targeting the underlying disease pathology rather than masking symptoms. 

The FDA’s accelerated approval of Aduhelm based on amyloid reduction rather than cognitive improvement lowered the bar for approval, though market access barriers remain. Medicare will cover about 80% of the cost of anti-amyloid antibodies, and CMS will only cover drugs using the accelerated approval pathway under an FDA-approved randomized controlled trial that evaluates clinical benefit, severely limiting patient access. 

In July 2023, Leqembi (lecanemab) became the first anti-amyloid antibody to gain full approval from the US FDA, after receiving accelerated approval from the agency in January the same year. Though competitor donanemab may have a slight efficacy advantage, physicians may favor Leqembi’s better safety profile. A traditional approval decision for Eli Lilly’s donanemab is expected by the end of 2023. Despite current uncertainties around efficacy and barriers to access, a high unmet need may ultimately create a lucrative market for anti-amyloid antibodies. If positive, data from subcutaneous formulations of anti-amyloid antibodies may generate excitement about a more desirable formulation coming down the pipeline. 

This Datamonitor Healthcare report contains a Disease Analysis module.