Groundbreaking treatments for Alzheimer's disease that work by removing a toxic protein called beta-amyloid from the brain may benefit whites more than Black Americans, whose disease may be driven by other factors, leading Alzheimer's experts told Reuters.
The two drugs – Leqembi, from partner biotech firms Eisai and Biogen, and an experimental treatment developed by Eli Lilly, donanemab - are the first to offer real hope of slowing the fatal disease for the 6.5 million Americans living with Alzheimer's.
Although older Black Americans have twice the rate of dementia as whites, they were screened out of clinical trials of these drugs at a higher rate, according to interviews with 10 researchers as well as 4 Eisai and Lilly executives.
Prospective Black volunteers with early disease symptoms did not have enough amyloid in their brains to qualify for the trials, the 10 researchers explained.
Hispanics, who experience dementia at one and a half times the rate of whites, were also excluded at a somewhat higher rate due to low amyloid, though the issue was not as pronounced as for Black people, five of the researchers said.
The growing evidence of a disparity around amyloid, a defining characteristic of Alzheimer's, is raising questions among some scientists about who will benefit from the two new treatments – the first ever proven to slow the rate of cognitive decline, the researchers said.
Referring to Leqembi, Dr. Crystal Glover, a social psychologist and expert in equity in aging research who leads clinical trial recruitment of the Rush Alzheimer's Disease Research Center in Chicago, asked: "Is this even applicable to the groups that are most at risk?"
About 20% of older Black people are estimated to have Alzheimer's or another dementia, twice the rate of White people and above the 14% of Hispanics.
Some researchers are asking whether Black patients are experiencing dementia due to causes other than Alzheimer's or whether the disease manifests differently in diverse populations who have higher rates of chronic conditions.
The disparity in beta-amyloid is adding to evidence that some health metrics may not work the same in diverse populations as they do in white people.
Leqembi is being launched at a price of $26,500 per year after it received full US regulatory approval this month.
A US Food and Drug Administration spokesperson said the agency was aware of the potential exclusion of some African Americans from the new treatments due to insufficient amyloid levels.
The spokesperson said the FDA encourages companies to increase enrollment of diverse populations in their ongoing trials. In April of 2022, the FDA recommended companies submit a diversity plan for enrollment.