NEW YORK: Ground-breaking treatments for Alzheimer’s disease that target the toxic protein beta amyloid in the brain may have a greater benefit for Whites compared to Blacks, according to leading Alzheimer’s experts interviewed by Reuters.
The two drugs, Leqembi developed by partner biotech firms Eisai and Biogen, and an experimental treatment by Eli Lilly called donanemab, offer hope for slowing the fatal disease that affects 6.5 million Americans. However, older Black Americans have double the rate of dementia compared to Whites, and they were excluded from clinical trials of these drugs at a higher rate.
Researchers explained that prospective Black volunteers with early disease symptoms did not have sufficient amyloid in their brains to qualify for the trials. Hispanics, who experience dementia at a higher rate than Whites, were also excluded to some extent due to low amyloid levels, but not as much as Black people.
This growing evidence of a disparity in amyloid levels raises questions about which populations will benefit the most from the new treatments, as the drugs are the first proven to slow cognitive decline.
Dr. Crystal Glover, who leads clinical trial recruitment at the Rush Alzheimer’s Disease Research Center in Chicago, expressed concerns about the applicability of these drugs to the groups most at risk. About 20% of older Black people are estimated to have Alzheimer’s or another dementia, twice the rate of White people.
Some researchers are now investigating whether Black patients might be experiencing dementia due to causes other than Alzheimer’s or if the disease manifests differently in diverse populations with higher rates of chronic conditions.
The issue of beta amyloid disparity adds to evidence that certain health metrics may not work the same in diverse populations as they do in White people.
Treatment for Alzheimer’s Dementia
Eisai is currently working with the National Institutes of Health (NIH) to test Leqembi’s effectiveness in preventing Alzheimer’s dementia among people with elevated amyloid but normal cognition, aiming for Black enrollment of at least 8% in the trial. So far, 95% to 98% of Black candidates are failing to meet the amyloid threshold required for inclusion.
The research into why Black and Hispanic people were screened out of trials at higher rates is ongoing, and there are hypotheses that their dementia may be caused by factors other than Alzheimer’s or that their disease is complicated by other factors such as small strokes.
Clinical trials often have low enrollment of diverse populations, with 80% of participants being White, according to a 2022 study. Alzheimer’s researchers have shifted towards detecting Alzheimer’s-associated proteins like amyloid rather than relying on outward signs like memory loss to identify patients with the disease.
Studies have indicated that some tests used to identify these proteins may perform differently among Black and White patients, leading to questions about the drivers of Alzheimer’s in different populations.
Efforts are being made to understand these disparities better to ensure that effective treatments are available to at-risk populations like Black Americans.
