Alzheimer disease (AD) research in 2026 has continued to expand across diagnosis, treatment, and the biological and environmental factors associated with disease. From advances in blood-based biomarkers and treatment administration to novel therapeutic targets and prevention strategies, progress throughout the year has also underscored remaining challenges in clinical care.

In recognition of World Alzheimer's Day, observed annually on September 21, NeurologyLive highlights select developments in AD research and clinical practice from 2026, reflecting ongoing efforts to improve care for patients, caregivers, and clinicians.

Featured stories include the FDA clearance of Roche's Elecsys pTau217 blood test, Fast Track designation for remlifanserin in AD psychosis, and approval of an at-home starting dose for subcutaneous lecanemab. Additional coverage explores a combination prevention trial, Down syndrome-associated dementia, the potential therapeutic role of NRN1, environmental risk factors, and the safety of oral anticoagulants alongside anti-amyloid therapies.

Together, these developments highlight an evolving AD landscape, from earlier identification and intervention to research examining the mechanisms and factors that may influence disease progression.

FDA Clears Roche's Single-Biomarker Elecsys pTau217 Blood Test for Alzheimer Disease

The FDA cleared Roche’s Elecsys pTau217, a blood test that uses a single biomarker to both rule in and rule out amyloid pathology in adults 55 years and older presenting with signs, symptoms, or complaints of cognitive decline associated with AD, across both primary and specialty care settings. Roche describes it as the first and only FDA-cleared, single-biomarker blood test that supports both rule-in and rule-out assessment of amyloid pathology using the same validated cutoffs across primary and specialty care.¹

"FDA clearance of Elecsys pTau217 marks an important milestone in Alzheimer's disease diagnosis and underscores Roche's continued leadership in advancing innovative solutions that can help patients get answers sooner," Dan Malarek, president and CEO of Roche Diagnostics North America, said in a statement.¹

FDA Grants Fast Track Designation to Remlifanserin for Alzheimer Disease Psychosis

In recent news, the FDA granted Fast Track designation to remlifanserin (ACP-204; Acadia Pharmaceuticals), an investigational selective serotonin 5-HT2A receptor inverse agonist, for the treatment of hallucinations and delusions associated with Alzheimer disease psychosis (ADP).²

“FDA Fast Track designation for remlifanserin underscores the significant unmet need for new treatment options for people living with Alzheimer disease psychosis, a serious condition for which there are currently no FDA-approved therapies,” Catherine Owen Adams, chief executive officer of Acadia, said in a statement.² “This is an important milestone for the remlifanserin program, and we look forward to sharing upcoming topline data from the RADIANT Phase 2 trial as we continue to advance remlifanserin as a potential new treatment option for patients and families impacted by this devastating condition.”

Alzheimer's Association Launches PROTECT-Cog Combination Prevention Trial

The Alzheimer's Association announced the launch of the PROTECT-Cog Study (Prevention of Risk fOr cogniTive dEcline through Combined Therapy) at the 2026 Alzheimer's Association International Conference (AAIC) in London. The global trial will evaluate whether combining a multidomain lifestyle intervention with a metabolism-targeting drug, such as a GLP-1 receptor agonist, further reduces cognitive decline risk beyond what lifestyle intervention alone has shown.³

"PROTECT-Cog builds directly on what we learned from U.S. POINTER and takes the next critical step in prevention science," Maria C. Carrillo, PhD, chief science officer and medical affairs lead at the Alzheimer's Association and principal investigator of the study, said in a statement.³ "By testing a combined approach that targets both lifestyle and biology, we have the opportunity to better understand how to meaningfully reduce the risk of cognitive decline before symptoms begin."

FDA Approves At-Home Starting Dose for Lecanemab, Marking First Subcutaneous Initiation Option for Alzheimer Disease Treatment

According to a new announcement, the FDA has approved a subcutaneous starting dose regimen for lecanemab-irmb (Leqembi; Eisai/Biogen), allowing patients with early AD to initiate treatment at home via weekly self-injection for the first time. The decision marks a meaningful shift in how the therapy can be delivered, removing the prior requirement that patients complete 18 months of intravenous infusions before becoming eligible for at-home subcutaneous dosing.^4,5

"What I find most encouraging about the approval is that this is the first time patients can start anti-amyloid Alzheimer's treatment from home. That's a real shift in how care can be delivered, not just a convenience upgrade. Alzheimer's care is moving toward combination therapy, much as cancer treatment did. But that only works if the treatments are practical enough for patients to stay on long-term,” Laura Nisenbaum, PhD, interim chief science officer at the Alzheimer's Drug Discovery Foundation (ADDF), told NeurologyLive^®. “A subcutaneous starting dose removes much of the infusion burden that makes long-term treatment harder to sustain. With nearly 75% of the pipeline now targeting pathways beyond amyloid and tau, the ability to deliver therapies in scalable ways will be essential to realizing the promise of combination therapy and precision medicine."

Understanding the History Behind Down Syndrome and Dementia

Down syndrome, caused by trisomy 21, is the most common chromosomal condition associated with intellectual disability, affecting approximately 1 in 700 live births in the United States.⁶ Improvements in medical care over the past several decades have led to a steady increase in life expectancy, with many individuals now living well into adulthood. As a result, the clinical landscape of Down syndrome has shifted, with neurologists increasingly encountering age-related neurological considerations in this growing population.

Alongside these demographic changes, there has been a renewed focus on better understanding the neurological profile of Down syndrome across the lifespan, including how underlying biology may influence later-life cognitive outcomes. Ongoing research efforts have begun to reshape how clinicians think about disease risk, monitoring, and long-term care in this population, setting the stage for a deeper exploration of the relationship between Down syndrome and neurodegeneration.

Study Identifies NRN1 as Therapeutic Target Candidate for Alzheimer Disease

A recent investigation leveraging large-scale AD consortia datasets reported that Neuritin-1 (NRN1), a synaptic plasticity–associated protein previously linked to cognitive resilience, demonstrates genomic and proteomic signals consistent with therapeutic target candidacy. All told, the findings position NRN1 as a biologically plausible target for therapeutic development in AD, particularly within synaptic resilience pathways, although the work remains preclinical and exploratory.⁷

Published in Alzheimer’s & Dementia, a central aim of the study was to validate commercially available antibodies capable of reliably detecting endogenous NRN1 protein. Among 3 tested polyclonal antibodies, Abcam ab64186 demonstrated specificity in rodent neurons and mouse brain tissue, with signal attenuation following siRNA-mediated knockdown.

Understanding the Links Between Air Pollution and Increased Alzheimer Disease Risk

AD is a progressive neurodegenerative disorder and the leading cause of dementia worldwide. It typically begins with episodic memory decline and progresses to impairments in language, executive function, and behavior. Pathologically, AD is marked by amyloid-β plaques, tau neurofibrillary tangles, and neuronal loss, particularly in the hippocampus.⁸ Neuropsychiatric symptoms, including depression and agitation, are common and contribute substantially to caregiver burden and reduced quality of life.⁹

As AD prevalence continues to rise, attention has increasingly turned toward identifying modifiable environmental risk factors. In a new national cohort study, lead author Yanling Deng, MBBS, PhD, postdoctoral researcher at Emory University, and colleagues examined the association between air pollution exposure and AD risk. Published in PLOS Medicine, findings suggest that PM2.5 exposure is linked to increased AD risk, largely through direct pathways rather than through comorbid conditions.¹⁰

Oral Anticoagulants Do Not Raise ARIA Risk of Anti-Amyloid Alzheimer Therapies, Study Shows

A systematic review and meta-analysis of randomized and non-randomized studies found no increased risk of amyloid-related imaging abnormalities (ARIA) among patients with Alzheimer disease (AD) receiving anti-amyloid monoclonal antibody therapies while on oral anticoagulants. The analysis addressed longstanding theoretical and empirical concerns that concomitant anticoagulant use could increase the frequency or severity of ARIA during anti-amyloid immunotherapy.¹¹

Published in the Journal of Neurology, Neurosurgery, & Psychiatry, the review included 5 eligible studies of anti-amyloid treatment for early AD that reported rates of ARIA or intracerebral hemorrhage (ICH) stratified by anticoagulant use. A total of 3837 participants were analyzed, including 1806 treated with lecanamab (Leqembi; Eisai) and 2031 treated with donanemab (Kisulna; Eli Lilly). Of note, non-human data and single-case reports were excluded from the analysis.

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1. Roche receives FDA clearance for Elecsys pTau217, advancing Alzheimer's disease assessment across primary and specialty care. News release. Roche Diagnostics. August 24, 2026. Accessed August 24, 2026. https://www.prnewswire.com/news-releases/roche-receives-fda-clearance-for-elecsys-ptau217-advancing-alzheimers-disease-assessment-across-primary-and-specialty-care-302857619.html
2. Acadia Pharmaceuticals Receives FDA Fast Track Designation for Remlifanserin in Alzheimer's Disease Psychosis. Acadia Pharmaceuticals. News Release. July 20, 2026. Accessed August 17, 2026. https://www.businesswire.com/news/home/20260720458854/en/Acadia-Pharmaceuticals-Receives-FDA-Fast-Track-Designation-for-Remlifanserin-in-Alzheimers-Disease-Psychosis
3. Alzheimer's Association launches "PROTECT-Cog" study to test U.S. POINTER lifestyle and GLP-1 or similar drug to cut risk of cognitive decline. News release. Alzheimer's Association. July 13, 2026. Accessed July 16, 2026. https://www.prnewswire.com/news-releases/alzheimers-association-launches-protect-cog-study-to-test-us-pointer-lifestyle-and-glp-1-or-similar-drug-to-cut-risk-of-cognitive-decline-302823408.html
4. FDA approves first at-home starting dose for Alzheimer's disease treatment. News release. US Food and Drug Administration. July 13, 2026. Accessed July 13, 2026. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-first-home-starting-dose-alzheimers-disease-treatment
5. ADDF Statement: FDA Approval of Subcutaneous Starting Dose for Leqembi Advances Alzheimer's Care Toward Combination Therapy Future. News release. ADDF. July 13, 2026. Accessed July 13, 2026. https://www.alzdiscovery.org/news-room/announcements/addf-statement-fda-approval-of-subcutaneous-starting-dose-for-leqembi-advances-alzheimers-care-toward-combination-therapy-future
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