The first published data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) study supports the hypothesis that higher levels of the amyloid protein in the brain represent an early stage of Alzheimer’s disease, according to the National Institutes of Health.
Results of an analysis of participant screening data for the study, published in JAMA Neurology, also show that amyloid burden in clinically normal older adults is associated with a family history of disease, lower cognitive test scores, and reports of declines in daily cognitive function. Major funding was provided by the National Institute on Aging (NIA), part of the NIH. All data is now freely available to the broader research community, the NIH said.
With completion expected in late 2022, the A4 study is an ongoing prevention trial launched in 2014 to test whether the drug solanezumab, a monoclonal antibody, could slow cognitive decline associated with elevated brain amyloid if started before clinical symptoms appear, NIH said. Amyloid, long considered a hallmark of Alzheimer’s disease, has been the target of therapies in clinical trials in people who already show symptoms of the disease.
The A4 study team was looking for cognitively normal participants with high levels of amyloid. They started by pre-screening more than 15,000 people who expressed interest in the trial. Of those 15,000, the researchers brought in 6,763 clinical trial volunteers for cognitive testing, clinical assessments and genotyping. After excluding 2,277 participants for cognitive and/or medical reasons, researchers used amyloid positron emission tomography (PET) imaging with 4,486 participants to measure amyloid accumulation in the brain. The PET imaging revealed 1,323 with elevated amyloid levels who were eligible to continue in the A4 study.
