The U.S. Food and Drug Administration (FDA) has granted accelerated approval to lecanemab (Leqembi), a new drug developed by Eisai and Biogen for the treatment of Alzheimer's disease. This marks a significant step forward in addressing the underlying pathology of Alzheimer's, rather than merely treating its symptoms. The decision follows Phase 3 trial results indicating a potential slowing of cognitive decline, although concerns remain regarding safety, specifically the risk of brain swelling and bleeding.
Clinical Trial Data and Safety Profile
Lecanemab is a monoclonal antibody designed to target and bind to amyloid beta, a protein that forms plaques in the brains of individuals with Alzheimer's disease. Data from an 18-month Phase 3 clinical trial, published in The New England Journal of Medicine, revealed that lecanemab reduced amyloid markers and resulted in moderately less cognitive and functional decline compared to placebo. However, the trial also highlighted adverse events, with 6.9% of participants discontinuing treatment due to these events, compared to 2.9% in the placebo group. Serious adverse events occurred in 14% of the lecanemab group and 11.3% of the placebo group.
The most common adverse events associated with lecanemab were infusion-related reactions and amyloid-related imaging abnormalities (ARIA), including brain swelling and bleeding. The prescribing information for Leqembi includes a warning about ARIA, noting that its frequency appeared higher in individuals carrying the APOE4 gene, a known risk factor for Alzheimer's. According to the study, mortality rates were similar between the lecanemab (0.7%) and placebo (0.8%) groups.
Pricing and Medicare Coverage
Eisai and Biogen have priced lecanemab at $26,500 per patient per year. This is slightly below the reduced price of their previous Alzheimer's drug, Aduhelm. The companies stated that this price reflects the value of the medication to society, estimated at around $37,000 per year based on quality of life gains, but was set lower to promote broader patient access.
However, insurance coverage for lecanemab is not guaranteed. The Centers for Medicare and Medicaid Services (CMS) previously restricted coverage of Aduhelm to patients enrolled in clinical trials due to concerns about its clinical benefit. CMS Administrator Chiquita Brooks-LaSure stated that her office would review Leqembi, but for now, its accelerated approval means it will be covered under the same restrictions as Aduhelm. The Alzheimer's Association has requested CMS to provide full and unrestricted coverage for FDA-approved Alzheimer's treatments.
Expert Perspectives
Dr. Richard Isaacson, director of the Alzheimer's Prevention Clinic in the Center for Brain Health at Florida Atlantic University's Schmidt College of Medicine, views lecanemab as "another tool" in the fight against Alzheimer's disease. He emphasized the importance of careful patient selection and monitoring, including genetic testing for APOE4. "I will prescribe this drug in the right person, at the right dose and in a very carefully monitored way, but this drug is not for everyone," he stated.
Implications for Alzheimer's Treatment
With over 6.5 million Americans currently living with Alzheimer's disease, and that number projected to reach 13.8 million by 2060, the approval of lecanemab represents a critical advancement. While not a cure, its potential to slow disease progression could provide individuals with more time to maintain their cognitive function and independence. The Alzheimer's Association has lauded the FDA's decision, emphasizing the importance of timely access to and coverage of this treatment and others in its class.
