Only a Small Percentage of Older Adults with Early Alzheimer’s Disease Eligible for New Monoclonal Antibody Treatments, Study Finds
A new study published in the medical journal Neurology has found that only a small percentage of older adults with early Alzheimer’s disease meet the eligibility criteria to receive new monoclonal antibody treatments. These drugs specifically target amyloid-ß plaques in the brain, which are considered an early sign of Alzheimer’s disease.
The research focused on the eligibility criteria for clinical trials of two monoclonal antibodies called lecanemab and aducanumab. At the time of the study, both drugs had received accelerated approval from the FDA, with lecanemab recently receiving traditional approval. Clinical trial results for these drugs were only available in individuals with mild cognitive impairment or mild dementia due to Alzheimer’s disease.
The study, conducted by researchers at the Mayo Clinic, included 237 people between the ages of 50 and 90 who had mild cognitive impairment or mild dementia. Brain scans showed increased amounts of amyloid-ß plaques in these individuals. The researchers then assessed the eligibility criteria for the clinical trials of lecanemab and aducanumab.
For lecanemab, the inclusion criteria required specific scores on thinking and memory tests, as well as a body mass index between 17 and 35. The researchers found that only 19 out of 237 participants, or 8%, would have been eligible for a lecanemab trial after applying the exclusion criteria, which included factors like stroke, cardiovascular disease, a history of cancer, or abnormal brain scan findings. However, when the exclusion criteria were modified to include all participants with mild cognitive impairment and not applying additional memory and thinking tests, the eligibility rate increased to 17%.
For aducanumab, the inclusion criteria required specific scores on thinking and memory tests and an age between 50 and 85. Out of the 237 participants, only 12 individuals, or 5%, would have been eligible for an aducanumab trial after applying the exclusion criteria, which were similar to those for lecanemab.
The study highlighted the underrepresentation of older Black and Hispanic individuals in clinical trials, despite their higher likelihood of having Alzheimer’s or other dementias. The researchers emphasized the need for more diverse populations in clinical trials to ensure that the eligibility criteria are applicable to all individuals at risk for cognitive impairment.
Study author Maria Vassilaki, MD, PhD, of the Mayo Clinic, acknowledged the limitations of the study, noting that the participants were primarily white. She reiterated the importance of assessing eligibility criteria in more diverse populations.
Vassilaki also stated that additional research is necessary 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 can become more widely available to people with Alzheimer’s disease.
The study was supported by various organizations, including the National Institutes of Health, the National Institute on Aging, and the Mayo Foundation for Medical Education and Research.
Further information on the study can be found in the journal Neurology.
Source:
American Academy of Neurology
Journal reference:
Pittock, R. R., et al. (2023) Eligibility for Anti-Amyloid Treatment in a Population-Based Study of Cognitive Aging. Neurology. doi.org/10.1212/WNL.0000000000207770.