Siemers, Eric

Abstract Advances in biomarker technology, digital cognitive assessments, and amyloid‐targeting therapies have redefined the opportunities for accurate and early diagnosis and care of Alzheimer's disease (AD). These advances also create new possibilities for intervention before the onset of cognitive impairment. This paradigm shift has increased the focus on Stages 1 and 2 of AD, in which individuals are cognitively unimpaired but exhibit biological evidence of disease. While early identification of AD offers an opportunity to intervene early to delay progression and preserve quality of life, it also presents complex challenges related to communicating diagnostic results to patients and their families, contextualizing the cost effectiveness of early diagnosis and treatment, and implementation of and equitable access to treatments. Recent, successfully enrolled, preclinical AD trials highlight the complex strategies required to identify asymptomatic, biomarker‐positive individuals on a large scale, and demonstrate critical knowledge gaps in inclusion, follow‐up, and long‐term outcome measurement. The Spring 2025 Alzheimer's Association Research Roundtable (AARR) meeting brought together academics, clinicians, industry, and regulatory leaders to exchange perspectives on current challenges, key learnings, and potential strategies for identifying and treating individuals in very early stages of AD, effectively and safely. This paper presents key takeaways from the Spring 2025 AARR meeting. Highlights New criteria for Alzheimer's disease (AD) enable early identification of AD pathology. Blood tests and digital cognitive assessment tools may facilitate early and personalized care. Plasma biomarkers may be scalable in clinical settings but need confirmation or follow‐up assessments in those individuals with equivocal results. Early therapy shows best results in people with lower initial amyloid and tau burden.

Abstract The Alzheimer's disease (AD) scientific field continues to make significant advances in early detection and treatments, which importantly rest on advances in our fundamental understanding of AD pathobiology and its contribution to cognitive decline. Clinical readouts of monoclonal antibodies against various forms of the amyloid beta (Aβ) protein indicate that the impact of these treatments may extend beyond reduction in amyloid plaques. The Alzheimer's Association Research Roundtable meeting held on May 17 and 18, 2022, reviewed our understanding to date of the impact of treatments targeting various species of Aβ; its impact on other related pathophysiology including tau; and ultimately, its effects on neurodegeneration and clinical decline, driven by the latest available data. Participants discussed the current evidence for a causal relationship among amyloid accumulation, tau alteration, and cognitive decline; the effect of anti‐amyloid therapies on clinical and biomarker endpoints; and how we can accelerate the pathway to therapeutic approval and what should guide us for the near future. Highlights The Alzheimer's Association Research Roundtable convened leaders from industry and academia, as well as patients, clinicians, and government and regulatory agency scientists to discuss the topic “Current Understanding of AD Pathophysiology & Impact of Amyloid‐beta Targeted Treatments on Biomarkers and Clinical Endpoints.” The totality of scientific evidence (clinical trials, animal data, modeling, and observational studies) on the relationship between amyloid beta (Aβ), amyloid, tau, and cognitive impairment is helping our understanding of the downstream effects and overall importance of lowering amyloid plaque load. Based on data from multiple phase 2 and 3 clinical trials of anti‐amyloid monoclonal antibodies, there is strong evidence to support that a sufficiently large reduction in amyloid plaque load to near‐normal levels is associated with positive changes in tau biomarkers and clinical endpoints. Reduction of Aβ plaque, measured easily by plasma amyloid biomarkers, is reasonably likely to predict benefit in clinical outcome measures.

Abstract The newly proposed revised criteria for diagnosis and staging of Alzheimer's disease (AD) by the Alzheimer's Association (AA) Workgroup represent a significant milestone in the field. These criteria offer objective measures for diagnosing and staging biological AD, bridging the gap between research and clinical care. Although implementation feasibility may vary across regions and settings, improving the availability and accuracy of biomarkers, especially plasma biomarkers, is expected to enhance the applicability of these criteria in clinical practice. The Fall 2023 Alzheimer's Association Research Roundtable (AARR) meeting served as a forum for gathering industry perspectives and feedback on these revised criteria, ensuring that the new criteria inform research, clinical trial design, and clinical care. In this article, we outline a summary of the newly proposed “Revised Criteria for Diagnosis and Staging of AD: AA Workgroup” and provide highlights from the AARR meeting in fall 2023. Highlights The Alzheimer's Association Research Roundtable (AARR) convened leaders from industry, academia, and government, to review the Revised Criteria for Diagnosis and Staging of AD: AA Workgroup , and gather industry perspectives and feedback on these revised criteria before its publication. The newly proposed revised criteria for diagnosis and staging of Alzheimer's disease (AD) by the AA's Workgroup represent a significant milestone, offering objective measures for the biological and staging of AD and bridging the gap between research and clinical care. Improving the availability and accuracy of biomarkers, especially blood‐based biomarkers (BBMs) is expected to improve clinical research and enhance the applicability of these criteria in clinical practice.

AbstractThe emergence of the United States Food and Drug Administration (FDA)‐approved amyloid‐targeting therapies for Alzheimer's disease challenges clinicians and healthcare providers with a transformative landscape. Effectively communicating the risks, benefits, burdens, costs, and available support associated with these novel disease‐modifying treatments to patients, families, and other healthcare providers is essential but complex. In response, the Alzheimer's Association's Clinical Meaningfulness Workgroup has proposed language surrounding treatment eligibility, benefits, amyloid‐related imaging abnormalities (ARIA), apolipoprotein E (APOE) genotyping, and treatment costs, serving as a resource to healthcare professionals in navigating discussions with patients and their families. As the landscape evolves with the approval of new Alzheimer's therapies, this resource stands poised for updates, ensuring its continued relevance in facilitating informed and meaningful patient‐provider dialogues.Highlights Effective communication of risks, benefits, burdens, and costs of FDA‐approved amyloid‐targeting antibodies is essential to patients, families, and healthcare providers. The Alzheimer's Association's Clinical Meaningfulness Workgroup provides language for physicians and healthcare providers around treatment eligibility, benefits, ARIA, APOE genotyping, and treatment costs. This supplementary resource may be updated as new AD therapies become approved.

Abstract The National Institute on Aging and the Alzheimer's Association convened three separate work groups in 2011 and single work groups in 2012 and 2018 to create recommendations for the diagnosis and characterization of Alzheimer's disease (AD). The present document updates the 2018 research framework in response to several recent developments. Defining diseases biologically, rather than based on syndromic presentation, has long been standard in many areas of medicine (e.g., oncology), and is becoming a unifying concept common to all neurodegenerative diseases, not just AD. The present document is consistent with this principle. Our intent is to present objective criteria for diagnosis and staging AD, incorporating recent advances in biomarkers, to serve as a bridge between research and clinical care. These criteria are not intended to provide step‐by‐step clinical practice guidelines for clinical workflow or specific treatment protocols, but rather serve as general principles to inform diagnosis and staging of AD that reflect current science. Highlights We define Alzheimer's disease (AD) to be a biological process that begins with the appearance of AD neuropathologic change (ADNPC) while people are asymptomatic. Progression of the neuropathologic burden leads to the later appearance and progression of clinical symptoms. Early‐changing Core 1 biomarkers (amyloid positron emission tomography [PET], approved cerebrospinal fluid biomarkers, and accurate plasma biomarkers [especially phosphorylated tau 217]) map onto either the amyloid beta or AD tauopathy pathway; however, these reflect the presence of ADNPC more generally (i.e., both neuritic plaques and tangles). An abnormal Core 1 biomarker result is sufficient to establish a diagnosis of AD and to inform clinical decision making throughout the disease continuum. Later‐changing Core 2 biomarkers (biofluid and tau PET) can provide prognostic information, and when abnormal, will increase confidence that AD is contributing to symptoms. An integrated biological and clinical staging scheme is described that accommodates the fact that common copathologies, cognitive reserve, and resistance may modify relationships between clinical and biological AD stages.

Abstract Alzheimer's disease (AD) clinical trials are designed and powered to detect the impact of a therapeutic intervention, and there has been considerable discussion on what constitutes a clinically meaningful change in those receiving treatment versus placebo. The pathology of AD is complex, beginning many years before clinical symptoms are detectable, with multiple potential opportunities for therapeutic engagement. Introducing treatment strategies early in the disease and assessing meaningful change over the course of an 18‐month clinical trial are critical to understanding the value to an effective intervention. With new clinical trial data expected soon on emerging therapeutics from several AD studies, the Alzheimer's Association convened a work group of experts to discuss key considerations for interpreting data from cognitive and functional measures and what is considered a clinically meaningful benefit or meaningful slowing of this fatal disease. Our expectations of outcomes from therapeutic interventions in AD may need to be modified.

Background: There is a need for feasible, scalable assessments to detect cognitive impairment and decline. The Cogstate Brief Battery (CBB) is validated for Alzheimer’s disease (AD) and in unsupervised and bring your own device contexts. The CBB has shown usability for self-completion in the home but has not been employed in this way in a multisite clinical trial in AD. Objective: The objective of the pilot was to evaluate feasibility of at-home, self-completion of the CBB in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) over 24 months. Methods: The CBB was included as a pilot for cognitively normal (CN) and mild cognitive impairment (MCI) participants in ADNI-2, invited to take the assessment in-clinic, then at at-home over a period of 24 months follow-up. Data were analyzed to explore acceptability/usability, concordance of in-clinic and at-home assessment, and validity. Results: Data were collected for 104 participants (46 CN, 51 MCI, and 7 AD) who consented to provide CBB data. Subsequent analyses were performed for the CN and MCI groups only. Test completion rates were 100%for both the first in-clinic supervised and first at-home unsupervised assessments, with few repeat performances required. However, available follow-up data declined sharply over time. Good concordance was seen between in-clinic and at-home assessments, with non-significant and small effect size differences (Cohen’s d between -0.04 and 0.28) and generally moderate correlations (r = 0.42 to 0.73). Known groups validity was also supported (11/16 comparisons with Cohen’s d≥0.3). Conclusion: These data demonstrate the feasibility of use for the CBB for unsupervised at-home, testing, including MCI groups. Optimal approaches to the application of assessments to support compliance over time remain to be determined.

AbstractThe Alzheimer's Association's Research Roundtable met in November 2017 to explore the new National Institute on Aging and the Alzheimer's Association Research Framework for Alzheimer's disease. The meeting allowed experts in the field from academia, industry, and government to provide perspectives on the new National Institute on Aging and the Alzheimer's Association Research Framework. This review will summarize the “A, T, N System” (Amyloid, Tau, and Neurodegeneration) using biomarkers and how this may be applied to clinical research and drug development. In addition, challenges and barriers to the potential adoption of this new framework will be discussed. Finally, future directions for research will be proposed.