Alzheimer’s Biomarkers: Diversity Barriers in Clinical Trials
Summary of teh Article: Racial and Ethnic Differences in Alzheimer’s Biomarkers & clinical Trial Eligibility
This article discusses a study investigating differences in Alzheimer’s disease biomarkers – specifically p-tau217 levels in blood - across racial and ethnic groups. Here’s a breakdown of the key findings:
New, Improved Test: The study utilizes the p-tau217 blood test, a more accurate method for detecting early signs of Alzheimer’s disease (specifically amyloid buildup) than previous tests. This test is becoming crucial for determining eligibility for Alzheimer’s treatment trials.
Disparities in Biomarker Levels: Researchers found that cognitively healthy individuals from African American, Hispanic, and Asian backgrounds were less likely to have elevated p-tau217 levels, indicating lower levels of amyloid in their brains. This meant they were less likely to qualify for a clinical trial (AHEAD Study) testing the drug lecanemab.
Confirmation of Previous Findings: This study confirms earlier research suggesting differences in amyloid prevalence across populations.
Paradoxical risk: The groups with lower amyloid levels (and therefore less likely to qualify for trials) are actually those at highest risk of developing dementia. This suggests amyloid may not be the primary driver of Alzheimer’s risk in these populations.
Trial Details: The study analyzed data from 6,437 participants (ages 55-80) in the AHEAD 3-45 trial. Non-Hispanic white participants were significantly more likely to meet the p-tau217 threshold for trial inclusion.
PET Scan Consistency: Interestingly, when researchers used PET scans (a direct measure of amyloid buildup) to confirm results, all racial/ethnic groups who qualified based on the p-tau217 test also showed amyloid buildup on the scans. This suggests the p-tau217 test is consistently identifying early disease pathology across groups. Further Research (APEX Study): To investigate these discrepancies, individuals who didn’t qualify for the AHEAD study are being enrolled in the amyloid Plasma Extension Study (APEX) to track other biomarkers over time and understand what does* drive dementia risk in these populations.
In essence, the study highlights the importance of considering racial and ethnic differences in Alzheimer’s research and suggests that current diagnostic and trial inclusion criteria, focused heavily on amyloid, may not be universally applicable. It raises the critical question of whether different biological pathways contribute to dementia risk in different groups.