A large global study provides new evidence supporting the use of blood biomarkers in an Alzheimer’s clinical trial to screen for elevated brain amyloid levels among potential participants who are cognitively unimpaired. The findings, published in JAMA Neurology, show that the relationship between the blood biomarker %p-tau217 and brain amyloid was largely similar across racial groups. The study also revealed that levels of the biomarker were generally lower among Asian and Black participants compared with White participants, and Hispanic participants compared with non-Hispanic participants. These differences raise questions about the factors that influence blood biomarker levels and how they relate to dementia risk across populations. The study included data from 15,612 adults, ages 55 to 80, collected at 106 research sites across Asia, Australia, Europe and North America. Participants were cognitively unimpaired and undergoing screening for the AHEAD 3-45 trials, which are testing lecanemab in people with certain levels of amyloid in the brain but no symptoms of Alzheimer’s disease. Participants underwent blood-based screening before eligible individuals proceeded to additional assessments, including PET scans. Although %p-tau217 levels differed across racial and ethnic groups, the marker showed similar relationships with Alzheimer’s-related measures across racial groups. Across the groups studied, higher %p-tau217 levels were consistently associated with higher levels of brain amyloid measured on PET scans. The study also found that carriers of the APOE ε4 variant, a major genetic risk factor for Alzheimer’s, generally had higher levels of %p-tau217 than adults without the variant—a pattern that largely held across racial and ethnic groups.
