MINNEAPOLIS — Despite the advancement in Alzheimer’s disease treatment through new drugs, only a small fraction of older adults displaying the early stages of the disease are eligible to receive the latest monoclonal antibody treatments. These drugs target amyloid-ß plaques in the brain, which are an early indication of Alzheimer’s.

Study researchers emphasized that clinical trial results for such drugs are only available for people displaying early symptoms like mild cognitive impairment or mild dementia due to Alzheimer’s.

Two of these monoclonal antibodies, lecanemab and aducanumab, had previously gained accelerated approval from the U.S. Food and Drug Administration. More recently, lecanemab received traditional FDA approval after evidence showed it could slow the progression of Alzheimer’s.

“There is hope that these new therapies for Alzheimer’s may slow progression of the disease for many people, although the fact remains that the drugs have only been studied in people with the earliest forms of the disease,” says study author Dr. Maria Vassilaki of the Mayo Clinic, a member of the American Academy of Neurology, in a media release.

“The inclusion and exclusion criteria of the clinical trials that led to FDA accelerated approval of these therapies form the basis of how people should be invited or discouraged from receiving one of these drugs. Our study estimates that only a small percentage of older people with early cognitive impairment due to Alzheimer’s may be eligible to be treated with monoclonal antibodies for amyloid-ß in the brain.”

Out of the 237 individuals between 50 and 90 with early Alzheimer’s symptoms in the study, only 19 (or 8%) would qualify for a lecanemab trial based on the clinical trial’s stringent criteria. Meanwhile, for aducanumab, 12 people (5%) met the criteria for eligibility.

Researchers further pointed out a concerning disparity in representation, noting that older Black and Hispanic individuals are more prone to Alzheimer’s or other dementias, yet remain underrepresented in clinical trials.

“Our study results show only a small percentage of people with early Alzheimer’s disease may be eligible to receive treatment, mostly due to chronic health conditions and brain scan abnormalities common in older adults,” notes Vassilaki.

“In general, clinical trial participants are healthier than the general population. Additional research is needed to examine the safety and efficacy of monoclonal antibodies targeting amyloid-ß plaques in larger, more diverse populations, as well as in less healthy populations, before these therapies may be more widely available to people with Alzheimer’s disease.”

A key limitation of the study was the predominantly White participant base. According to the team, testing these eligibility criteria in a more diverse group remains essential.

The study is published in the journal Neurology.

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