Biogen and Eisai’s Alzheimer’s drug shown to slow memory decline in confirmatory study

Biogen and Eisai have reported full results from the successful phase 3 trial of Alzheimer’s disease (AD) drug, lecanemab, marking the first time a treatment has been shown to both reduce the disease in the brain and slow memory decline.

The detailed results, published in the New England Journal of Medicines, were presented by Eisai at the 2022 Clinical Trials on Alzheimer’s Disease conference in San Francisco.

The Clarity AD trial was a global phase 3 confirmatory placebo-controlled, double-blind, parallel-group, randomised clinical trial to assess a 10mg/kg bi-weekly dosage of lecanemab, an investigational anti-amyloid beta protofibril antibody, in 1,795 people with early AD.

The recruitment strategy for the trial ensured greater inclusion of ethnic and racial populations in the US, resulting in approximately 25% of the total US enrolment including Hispanic and African American persons living with early AD.

The study met its primary endpoint and reduced clinical decline on the global cognitive and functional scale – Clinical Dementia Rating-Sum of Boxes (CDR-SB) – by 27%.

All key secondary endpoints also showed highly statistically significant results compared with placebo, the companies reported, including other measures of cognition and daily function.

Dr Susan Kohlhaas, director of research at Alzheimer’s Research UK, said the findings represent a “major step forward” for dementia research and could "herald a new era for people with Alzheimer’s disease”.

“The road to an anti-amyloid treatment has been a long one and people with Alzheimer’s have seen many disappointing setbacks. We hope that this drug will make it to patients, but it won’t be suitable for everyone with Alzheimer’s, and it’s only a first step on the journey towards a cure,” she added.

In terms of safety, however, lecanemab was associated with brain swelling in nearly 13% of patients, but most only had evidence of problems on brain scans. Fewer than one in 30 had symptoms such as headaches, visual disturbance or confusion. Some patients also experienced bleeding in the brain.

“The benefits of taking lecanemab in the trial were modest, but the challenge and opportunity remains within dementia research to build on these findings into an era where we’re developing multiple treatments against different aspects of Alzheimer’s disease to slow and stop the disease,” said Kohlhaas.

The US Food and Drug Administration accepted Eisai’s Biologics Licence Application for lecanemab under the accelerated approval pathway and granted Priority Review in July 2022, and agreed that the results of Clarity AD could serve as the confirmatory study to verify the clinical benefit of lecanemab.