There have been a number of drugs which have been shown to slow beta-amyloid plaque development, but this is the first to show any reduction in cognitive decline in association with it. For instance, the same companies who development lecanemab also trialed aduhelm, which reduced plaques with no change in patient cognitive abilities. This was approved by the FDA as well with much controversy, resulting in the resignation of 3 members of the advisory committee. However, the results are modest with some scientists claiming it will not result in any perceivable difference for the patient. Indeed the above poster is correct in that there is a growing concern whether beta-amyloid plaques are the cause of the disease, as the foundation of the hypothesis has been called into suspect due to potentially fraudulent work. There was an interesting write up recently in Science about it. Now, this is not my field, but I'm curious of what may come out of it. It may be akin to a sort of Piero Anversa c-kit stemcell fall out, resulting in the retraction of a slew of studies.