Recent Advances in Biomarker Research for Alzheimer’s Disease: Clinical Utility, Progress, and Racial/Ethnic Disparities
Abstract
Alzheimer’s disease (AD) biomarkers have undergone a transformative shift from invasive cerebrospinal fluid (CSF) and expensive imaging to accessible blood-based assays. This paper synthesizes recent findings from community-based cohorts, clinical trial registries, and primary care studies to evaluate the progress of biomarker research. Key markers such as phosphorylated tau (p-tau) isoforms, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) demonstrate high prognostic and diagnostic accuracy. Furthermore, we examine the critical issue of racial and ethnic disparities in AD progression, biomarker expression, and treatment access, with a specific focus on recent breakthroughs in Asian populations. While blood biomarkers show promise for universal application, significant gaps remain in ensuring equitable diagnosis and care across diverse populations.
Introduction
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques and tau tangles. Historically, diagnosis relied on clinical symptoms, which often appear decades after pathological onset. The development of the AT(N) framework—categorizing biomarkers by Amyloid, Tau, and Neurodegeneration—has revolutionized the field. Recent research focuses on blood-based biomarkers (BBMs) to enable early detection and monitor disease-modifying therapies (DMTs). This report integrates data from pivotal studies and additional research to provide an update on biomarker progress and the impact of racial/ethnic differences on AD outcomes.
Progress in Biomarker Research and Clinical Utility
1. Predictive Utility in Community Settings
A large-scale study from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) evaluated 2,148 dementia-free adults over a 10-year period. The findings revealed that plasma p-tau217, p-tau181, NfL, and GFAP are potent predictors of incident dementia. Specifically, p-tau217 outperformed other markers for AD-specific prediction, while NfL was superior for all-cause dementia. These biomarkers exhibited high negative predictive values (NPVs >90%), making them excellent "rule-out" tools for primary care settings [1].
2. Biomarkers in Clinical Trials
Biomarkers are now central to AD drug development. As of 2025, 84% of active disease-targeted therapeutic (DTT) trials incorporate at least one biomarker. They serve multiple "Contexts of Use" (COUs), including trial enrichment (selecting the right participants), pharmacodynamic monitoring (measuring drug effect), and safety surveillance. The FDA’s approval of plasma p-tau217 via the Lumipulse platform marks a milestone in transitioning from research to clinical practice [2] [3].
3. Implementation in Primary and Secondary Care
Recent evidence from a study of 1,213 patients demonstrates that blood-based biomarkers, particularly the Amyloid Probability Score 2 (APS2) and %p-tau217, achieve diagnostic accuracy of approximately 90% in both primary and secondary care. This accuracy significantly exceeds that of traditional clinical assessments by physicians, suggesting that BBMs can streamline the diagnostic pathway and reduce the need for specialized PET scans or lumbar punctures [5].
4. Cellular and Molecular Pathogenesis
The AT(N) system is supported by a deeper understanding of cellular mechanisms, including mitochondrial dysfunction and autophagy. Biomarkers like GFAP indicate astrocyte activation and neuroinflammation, while NfL reflects axonal damage. Combining these markers with p-tau isoforms enhances the ability to capture the multifaceted biology of AD [4].
Racial and Ethnic Disparities in AD
Progression and Prevalence
Research consistently shows that Black/African American and Hispanic/Latino populations are at a higher risk for AD compared to non-Hispanic Whites. Black Americans are approximately twice as likely, and Hispanics 1.5 times as likely, to develop AD. Despite this higher prevalence, these groups are often diagnosed at later stages of the disease, leading to more rapid clinical progression and higher caregiver burden [6] [7].
Biomarker Consistency and Differences
A critical question in the field is whether biomarker thresholds should vary by race. Recent studies, such as those by Brickman et al. (2025), suggest that common blood-based markers like p-tau217 and NfL are largely consistent across White, Black, and Hispanic groups, supporting the use of universal diagnostic cutoffs. However, some research indicates that for the same level of amyloid burden (measured by PET), Black participants may exhibit lower levels of CSF tau, potentially complicating the interpretation of traditional "A+T+" profiles [8] [9].
Latest Updates in Asian Populations
Recent research in 2025 and 2026 has significantly expanded our understanding of AD biomarkers in Asian populations, who have historically been underrepresented in clinical trials (often <3% participation).
•High Accuracy in High-CeVD Cohorts: A landmark study from the National University of Singapore (2025) confirmed that plasma p-tau217 is highly accurate for detecting Aβ pathology in Asian populations, even in those with a high burden of cerebrovascular disease (CeVD). This is a critical finding as CeVD is more prevalent in Asian demographics and can often confound AD diagnosis [12].
•Predictive Value for Cognitive Decline: Elevated plasma p-tau217 levels in Asian cohorts have been correlated with faster cognitive decline and hippocampal atrophy, reinforcing its role as both a diagnostic and prognostic tool [13].
•The ACAD Study: The Asian Cohort for Alzheimer’s Disease (ACAD) study, a major multi-center initiative funded by the NIH, is currently recruiting 5,000 participants to identify population-specific genetic variants and validate blood biomarkers (Aβ40, Aβ42, GFAP, NfL, p-tau217) specifically for Asian Americans and Canadians. This study aims to address cultural and linguistic barriers that have historically led to inaccurate diagnoses in these groups [14].
Treatment Disparities
Disparities extend to the initiation and persistence of treatment. Black and Hispanic patients are significantly less likely to be prescribed anti-dementia medications like acetylcholinesterase inhibitors (AChEIs) or memantine. Furthermore, these populations are historically underrepresented in clinical trials for new DMTs, which limits the generalizability of trial results and exacerbates inequities in access to cutting-edge therapies [10] [11].
Discussion
The progress in AD biomarker research is undeniable. The transition to blood-based testing offers a scalable solution for early diagnosis and trial recruitment. However, the "modest" positive predictive value (PPV) in community settings suggests that BBMs should be used as part of a multi-stage diagnostic process.
The findings on racial and ethnic disparities highlight a significant challenge. While the biological markers themselves may be consistent across groups, the social determinants of health—including education, cardiovascular comorbidities, and systemic bias in healthcare—drive the observed disparities in AD outcomes. The recent focus on Asian populations and the validation of markers like p-tau217 in high-CeVD contexts are vital steps toward a more inclusive and accurate global diagnostic framework.
Conclusion
Blood-based biomarkers have reached a level of maturity that allows for their integration into routine clinical care and optimized trial designs. They are making significant progress in identifying AD pathology early and accurately across diverse racial and ethnic groups. To fully realize their potential, the medical community must address the systemic barriers that prevent minoritized groups from receiving timely diagnoses and effective treatments.
References
1.Grande G, et al. (2025). Blood-based biomarkers of Alzheimer’s disease and incident dementia in the community. Nature Medicine. https://www.nature.com/articles/s41591-025-03605-x
2.Cummings J. (2025). The roles of biomarkers in Alzheimer’s disease clinical trials. ScienceDirect. https://www.sciencedirect.com/science/article/pii/S1878747925002892
3.Osse AML, et al. (2026). Biomarkers in Alzheimer’s disease clinical trials: 2025. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC12914139/
4.Wang H, Qin H. (2023). Biomarkers associated with the pathogenesis of Alzheimer’s disease. Frontiers in Cellular Neuroscience. https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2023.1279046/full
5.Palmqvist S, et al. (2024). Blood Biomarkers to Detect Alzheimer Disease in Primary Care and Secondary Care. JAMA. https://jamanetwork.com/journals/jama/fullarticle/2821669
6.Alzheimer's Association. (2021). Race, Ethnicity, and Alzheimer's. https://aaic.alz.org/downloads2020/2020_Race_and_Ethnicity_Fact_Sheet.pdf
7.ASPE. (2022). Federal efforts to address racial and ethnic disparities in Alzheimer's disease. https://aspe.hhs.gov/sites/default/files/documents/5f3fc5aa6ae780f739265d40f20fc456/federal-racial-ethnic-disparities-adrd.pdf
8.Brickman AM, et al. (2025). Alzheimer Disease Blood Biomarker Concentrations Across Race and Ethnicity Groups in Middle-Aged Adults. JAMA Network Open. https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2841743
9.Wilkins, C. H., et al. (2023). Racial differences in Alzheimer's disease biomarkers. Washington University School of Medicine.
10.Olchanski N, et al. (2023). Alzheimer's disease medication use and adherence patterns by race and ethnicity. Alzheimer's & Dementia. https://alz-journals.onlinelibrary.wiley.com/doi/abs/10.1002/alz.12753
11.UC Davis Health. (2024). Study finds disparities in diagnosis and treatment of dementia. https://health.ucdavis.edu/news/headlines/study-finds-disparities-in-diagnosis-and-treatment-of-dementia/2024/01
12.National University of Singapore. (2025). Study confirms accuracy of blood test for early Alzheimer's detection in Asian populations. ScienceDaily. https://www.sciencedaily.com/releases/2025/03/250324220621.htm
13.Chong J, et al. (2025). Plasma P‐tau217, GFAP, and NfL as biomarkers for Alzheimer's disease in Asian cohorts. Alzheimer's & Dementia. https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.70987
14.Mount Sinai Health System. (2025). Closing Alzheimer’s Disease Research Gaps in Asians. Mount Sinai Reports. https://reports.mountsinai.org/article/psych2025-02-acad-alzheimers-study-in-asians-1
These visuals were created to help visualize complex processes from the research papers (e.g., APP cleavage pathways and the sequential rise of biomarkers decades before symptoms), without pulling from copyrighted figures in the linked articles or elsewhere. The papers themselves contain their own figures (mostly graphs and charts under Creative Commons or journal licenses), but the rendered images here are independent AI interpretations.
Comments
Post a Comment