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Promising Results from Alzheimer’s Drug Trial


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Last month, pharmaceutical companies Eisai and Biogen announced positive results from a phase 3 clinical trial of an Alzheimer’s drug called lecanemab.

The trial spanned an 18-month period and enrolled about 1,800 participants with mild cognitive impairment or early-stage Alzheimer’s disease.

Compared to those who did not receive the drug, trial participants who received lecanemab experienced a 27% slower rate of cognitive decline.

“The Eisai announcement is good news for the Alzheimer’s field,” said Dr. Michael Weiner, the Principal Investigator of the Brain Health Registry. “Although these findings are significant, it’s important to note that the drug does not stop the progression of decline or restore function to those with impairment.”

Lecanemab was also associated with side effects, including swelling and bleeding in the brain. Most side effects were detected by MRI and caused no symptoms. There was a relatively low incidence of serious side effects.

Lecanemab is a type of antibody that targets clumps of amyloid protein in the brain. These amyloid plaques damage brain cells, contributing to memory and thinking issues in Alzheimer’s and related forms of dementia.

Findings from the lecanemab study support the “Amyloid Hypothesis” of Alzheimer’s, which proposes that the disease is linked to the buildup of amyloid protein in the brain.

Other treatments aimed at amyloid are currently being investigated. Alzheimer’s researchers also continue to seek drug targets other than amyloid, including another protein in the brain called tau.

Lecanemab is a “disease-modifying” therapy, meaning it targets the underlying biology of Alzheimer’s disease, rather than just easing symptoms. This distinguishes it from most other drugs on the market, aside from Biogen’s drug Aduhelm. Despite controversies around the results of two clinical trials, the FDA approved Aduhelm in June 2021. However, the Center for Medicare Services (CMS) did not approve Aduhelm for reimbursement. At present, Biogen is not actively marketing Aduhelm.

Eisai recently filed for accelerated FDA approval for lecanemab. This means that the drug could be approved as soon as early 2023. Eisai will also very likely request that CMS provide reimbursement. Most experts believe that, if approved, lecanemab may become available to the public in 2023 or 2024.

Results from the lecanemab trial will be presented during the annual Clinical Trials on Alzheimer’s Disease conference in November 2022. This will give researchers and the public a clearer understanding of the drug’s potential.

Measuring Cognitive Decline


The Eisai trial used a tool called the Clinical Dementia Rating (CDR) to assess lecanemab’s effectiveness at slowing cognitive decline.

The CDR is a commonly used scale that measures the severity of dementia symptoms.

The difference in CDR scores between participants who received lecanemab versus those who did not was 0.45 points, a minor, but significant difference.

Brain Health Registry researchers are currently working on developing on online version of the CDR, as part of our Electronic Validation Study.

Findings from this project could help researchers identify Alzheimer’s risk sooner and more efficiently. Because this version of the CDR could be administered online rather than in a clinic by a trained assessor, it could make research studies more accessible and scalable.

To read more about the Electronic Validation Study, click here.