No one expected this. In March, Biogen and its collaboration partner, Tokyo-based Eisai, announced they were discontinuing the global Phase III clinical trials, ENGAGE and EMERGE, of aducanumab in patients with mild cognitive impairment from Alzheimer’s and mild Alzheimer’s dementia. Biogen was also discontinuing the EVOLVE Phase II trial and the long-term extension PRIME Phase Ib trial of the drug. An independent data monitoring committee indicated they probably wouldn’t hit their primary endpoint.
Many thought it was the final nail in the amyloid theory of Alzheimer’s disease. Aducanumab is an antibody targeting beta-amyloid, one of the proteins that accumulates in the brains of Alzheimer’s patients and was believed to be one of the primary causes of the disease.
Today, the two companies announced that after discussions with the U.S. Food and Drug Administration (FDA), Biogen will pursue regulatory approval for aducanumab. The Phase III EMERGE trial met its primary endpoint, showing a significant decrease in clinical decline. The company now believes that data from a subset of patients in the trial who were given a high enough dose of the drug had significant benefits on measures of cognition and function, including memory, orientation, and language. There were also benefits on activities of daily living—conducting personal finances, household chores like cleaning, shopping, and laundry, and independently traveling outside of the home.
