Eisai, Biogen share landmark Alzheimer's trial results

Sept. 28, 2022

Eisai and Biogen announced that their jointly-developed investigational mAb slowed progress of the Alzheimer's disease by 27% compared with a placebo in a large phase 3 trial of patients in early stages of the disease.

According to Tokyo-based Eisai, the global 1,795-person Clarity AD trial of lecanemab met the primary endpoint and all key secondary endpoints with highly statistically significant results. The primary endpoint, Clinical Dementia Rating-Sum of Boxes (CDR-SB), is a numeric scale used to quantify the various severity of symptoms of dementia.

Lecanemab is an investigational anti-amyloid beta protofibril antibody for the treatment of mild cognitive impairment due to Alzheimer’s disease and early Alzheimer’s disease with confirmed presence of amyloid pathology in the brain. The drug targets a toxic protein plaque known as amyloid beta — long been considered crucial to slowing the progression of the fatal brain disease.

This 'amyloid hypothesis' however, has been historically tough to prove. Biogen knows this all too well. The U.S. FDA gave Aduhelm the green light back in June of last year — amid much debate over its effectiveness — making it the first new treatment for the memory-robbing disease in nearly 20 years. The approval was based on the drug's plaque-clearing ability — rather than proof that it helped slow cognitive decline. Earlier this year, citing unconvincing demonstrations of the drug’s effectiveness, the U.S. Medicare program decided to cover the drug only for patients who were participating in clinical trials.

But according to Eisai, the lecanemab Clarity AD study results prove the amyloid hypothesis. And the market seems to agree. BMO Capital Markets analyst Evan Seigerman called the data an "unequivocal win" for Biogen and Alzheimer's patients, as both company's stocks skyrocketed.

Lecanemab's PDUFA is set for January 6, 2023. Eisai says the FDA has agreed that the results of Clarity AD can serve as the confirmatory study to verify the clinical benefit of the drug.