On July 6, 2023, the U.S. Food and Drug Administration (FDA) approved lecanemab (Leqembi) for the treatment of Alzheimer's dementia (AD) patients. In 2 clinical trials, lecanemab reduced amyloid in the brain and slowed cognitive decline. Here, I review in detail the clinical trial by van Dyck et al. (2023) entitled "Lecanemab in early Alzheimer's disease", published in The New England Journal of Medicine on January 5, 2023. In this 18-month trial, lecanemab did not slow cognitive decline in women. This is especially significant because women have a twofold increased risk of AD compared to men, that is, there are 2 times more women than men living with AD. Lecanemab did not slow cognitive decline in APOE4 carriers; rather, it enhanced the decline in study participants with 2 APOE4 genes. This is bad news for AD patients, 60-75% of whom carry at least 1 APOE4 gene. These negative results regarding lecanemab's therapeutic value make me wonder if the approval of lecanemab was the worst decision of the FDA up till now, after the approval of aducanumab on June 7, 2021.
Keywords: APOE4; Alzheimer; clinical trial; immunotherapy; lecanemab.