A4's screening data show link between high amyloid levels and early Alzheimer's disease

Data published from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) study on April 6 show that early stages of Alzheimer's disease could be represented by high levels of amyloid protein in the brain. 

Screening data from the study supports a hypothesis that higher levels of amyloid in the brain lead to early stages of the disease, according to National Institutes of Health. The ongoing A4 study, which will be completed in 2022, is a prevention trial aiming to slow the cognitive decrease that's often associated with higher levels of amyloid. 

“A major issue for amyloid-targeting Alzheimer’s disease clinical trials, and one that is being addressed with the A4 study, is that previous trials may have been intervening too late in the disease process to be effective,” NIA Director Dr. Richard J. Hodes said in the news release. “A4 is pioneering in the field because it targets amyloid accumulation in older adults at risk for developing dementia before the onset of symptoms.”

The results of the screening data for A4 also suggest that older adults with amyloid burden tend to have a family history of Alzheimer's disease, lower cognitive test scores and daily cognitive function decreases, according to NIH. 

The A4 study recruited volunteers who appeared cognitively normal, according to NIH. Over 15,000 people were interested in volunteering and of those, 4,486 were chosen to participate in measuring amyloid accumulation in their brains. 

Amyloid position emission tomography (PET) imaging was used to measure the amount of amyloid in the participants' brains, according to NIH. PET showed that 1,323 participants had higher levels of amyloid and these were the volunteers that were able to continue with the study. 

Laurie Ryan, Ph.D., chief of the Dementias of Aging branch in NIA's Division of Neuroscience, said PET imaging shows researchers that even individuals who are cognitively normal can have high levels of amyloid. 

“Alzheimer’s disease is never going to have a one-size-fits-all treatment," lead study author Dr. Reisa Sperling at Brigham and Women's Hospital and Harvard Medical School said in NIH's news release. "We’re likely to need different treatments, even combinations of therapies, for different individuals based on their risk factors.”