Bio‐Hermes: A study to assess the relationship of blood and digital biomarkers with Aβ PET scans in older persons with normal cognition, MCI or mild AD

Background

Recently developed blood and digital biomarkers may enable the identification of persons with amyloid deposits in the brain. While these biomarkers are promising, most haven’t been evaluated in populations like those screened for clinical treatment trials or in populations with racial and ethnic diversity similar to the US population. The Global Alzheimer’s Platform Foundation® (GAP) completed its biomarker study (Bio‐Hermes) comparing results of blood and digital biomarker tests with brain amyloid PET scans and traditional cognitive tests. The trial enrolled 1,002 participants in three cohorts: Cognitively Normal (CN), Mild Cognitive Impairment (MCI), and Mild AD.

Method

Within 18 months, 17 sites enrolled 1,002 participants (60‐85 y/o) in clinically defined cohorts of: CN (N = 417), MCI (N = 312), and Mild AD (N = 273). Traditional and digital cognitive testing, amyloid PET imaging, biospecimen collection, and speech analytics were performed. A subset of participants received a retinal exam. Blood biomarkers included, Aß 42/40, p‐Tau181/217/231, NfL, GFAP, full genome sequencing, including APOE status, and proteomics. Digital biomarkers included memory recall, executive functions, and drawing‐based and speech elicitation tasks. Blood biomarkers’ relationship to amyloid PET was measured using Spearman’s rank correlation. A ROC curve analysis will assess the sensitivity and specificity of each biomarker and combination of biomarkers compared with amyloid positivity from PET.

Result

Statistical models to be competed in April 2023 for presentation.

24% of participants were from underrepresented populations (URP) either African American, Hispanic or other. The CN cohort was 61% female, with 21% amyloid PET Positive; the MCI cohort was 54% female with 34% amyloid PET Positive; the Mild AD cohort was 51% female with 62% amyloid PET Positive. Penalized multiple regression will be used to predict amyloid level (continuous) and amyloid positivity status. Candidate predictors include cohorts, blood‐based biomarkers, cognitive assessments (rating scales and digital), retinal measurements, and speech recognition digital biomarkers.

Conclusion

Bio‐Hermes generated a unique, well‐characterized, diverse sample set that determined the utility of several promising biomarkers. Validation of these biomarkers will expedite AD clinical trial enrollment by quickly identifying appropriate participants while reducing the variability and burden of screen failures from high‐cost brain scan procedures.