Aducanumab is a human monoclonal antibody that has been studied for the treatment of Alzheimer's disease (AD). It was developed by Biogen Inc., which licensed the drug candidate from Neurimmune, its discoverer. The antibody targets aggregated forms of β-amyloid found in the brains of people with Alzheimer’s disease, in the hopes of reducing its buildup. Biogen halted development of the drug in March 2019 after preliminary data from two phase III trials suggested it would not meet the primary endpoint. On 22 October 2019 Biogen announced that it would be re-starting the FDA approval process for aducanumab stating that new analysis of a larger dataset showed that the drug reduced clinical decline in patients with early Alzheimer's disease when given at higher doses. The reanalysis of the data from the discontinued trial concluded that patients receiving a high dose had a 23% reduction in their rate of decline.
Interim results from the second Phase 1 study of the drug were reported in March 2015.
A phase 1b study was published in August 2016, based on one year of "monthly intravenous infusions" of aducanumab, with brain scans to measure amyloid plaques. Phase 3 clinical trials were ongoing in September 2016, but were canceled in March 2019 after "an independent group's analysis show[ed] that the trials were unlikely to 'meet their primary endpoint.'"
Despite this, in October 2019 the company announced their intention to seek regulatory approval, following a reanalysis of the data.