Biogen stocks plummet after failed Alzheimer’s trials

March 25, 2019

After losing more than $18 billion of its value last week after ending two late-stage trials of their experimental Alzheimer’s disease treatment, Biogen said it would buy back shares worth $5 billion.

The Phase 3 trials, ENGAGE and EMERGE, were designed to evaluate the efficacy and safety of aducanumab in patients with mild cognitive impairment due to Alzheimer’s disease and mild Alzheimer’s disease dementia.

The trial fails were particularly disappointing because they had come farther along than other studies in terms of potentially treating patients with mild cognitive impairment due to Alzheimer's disease or mild Alzheimer's disease dementia.

The market damage was so bad that Biogen has lost its title as Massachusetts' most valuable biotech to Vertex Pharmaceuticals.

Read the Boston Globe coverage.