Alzheimer’s disease research has undergone a profound transformation in the last five years. For the first time in history, there are treatments that alter the biological course of the disease rather than just managing symptoms. There are blood tests that can detect pathology years before cognitive decline. And the understanding of what drives the disease, once narrowed to two proteins, amyloid and tau, has expanded to encompass the immune system, vascular biology, and genetics in ways that are reshaping the therapeutic pipeline.
A comprehensive review published July 9 in Cell (DOI: 10.1016/j.cell.2026.06.006) by Michelle D. Rudman, Jason D. Ulrich, and David M. Holtzman of Washington University in St. Louis provides a synthesis of this transformed landscape. The review, spanning 32 pages, identifies four key areas that have driven the field’s evolution: sensitive and specific biomarkers, disease-modifying therapies that validate the amyloid hypothesis, the discovery of rare protective APOE variants, and the recognition that both the innate and adaptive immune systems contribute actively to neurodegeneration.
Amyloid: From Hypothesis to Clinical Validation
The most consequential change is clinical. The FDA approvals of lecanemab (Leqembi) and donanemab (Kisunla), anti-amyloid antibodies that slow cognitive decline by 27-35%, represent the first disease-modifying therapies for Alzheimer’s. After decades of failed clinical trials, these results provide strong support for the amyloid hypothesis as the initiating mechanism in the pathogenic cascade, while also making clear that amyloid removal alone is not sufficient to stop or reverse established disease.
“Amyloid accumulation begins approximately 20 years before cognitive impairment onset,” the authors note. Anti-amyloid antibodies are now understood to be most effective when administered early, before significant tau pathology and neurodegeneration have taken hold. The review acknowledges the treatment’s limitations: amyloid-related imaging abnormalities (ARIA-E and ARIA-H) remain a significant clinical concern, and the modest effect sizes mean patients still progress, just more slowly.
Tau: The Next Therapeutic Frontier
If amyloid initiates the disease, tau is what drives its progression. Tau pathology, hyperphosphorylated tau aggregating into neurofibrillary tangles, correlates with neurodegeneration and cognitive decline more closely than amyloid burden alone. The review positions anti-tau therapies as the next major frontier in Alzheimer’s treatment, with tau immunotherapies, antisense oligonucleotides, and aggregation inhibitors all in various stages of clinical development.
The interplay between amyloid and tau is central to the current model: amyloid pathology is thought to trigger or accelerate tau pathology, and intervening at either point in this cascade may provide benefit. Combination therapy targeting both proteins is considered the most likely path to optimal outcomes.
Neuroinflammation: Beyond Microglia
One of the most significant conceptual advances the review catalogues is the expanded understanding of neuroinflammation in Alzheimer’s. The field has moved well beyond viewing microglia as merely reactive, clearing debris and responding to pathology, to recognizing active immune dysregulation as a core disease mechanism.
The review emphasizes the involvement of both the innate and adaptive immune systems. TREM2, a receptor expressed on microglia, has emerged as a critical regulator of microglial function in Alzheimer’s, and TREM2 agonistic antibodies are among the immunomodulatory approaches now in development. The adaptive immune system, T cells and B cells, is increasingly recognized as playing a role that goes beyond incidental infiltration.
APOE: Protective Variants Rewrite the Genetic Playbook
The discovery of rare protective variants in the APOE gene, most notably the Christchurch mutation, has been transformative. APOE4 is the strongest genetic risk factor for late-onset Alzheimer’s, and understanding how protective variants mitigate risk is opening entirely new therapeutic strategies. The review discusses efforts to mimic these protective effects through both genetic and pharmacological approaches.
The Current Pipeline and Future Directions
The review characterizes the current era as one of disease-modifying therapy validation. After decades of clinical trial failures, the field now has a validated target (amyloid), a validated modality (antibodies), and a validated biomarker framework (plasma p-tau217) for patient selection and monitoring.
Ongoing directions include third-generation anti-amyloid antibodies with improved safety profiles, tau immunotherapies, anti-inflammatory agents, GLP-1 receptor agonists repurposed from diabetes, and anti-tau antisense oligonucleotides. The authors also highlight combination therapy as the most likely path forward, analogous to cancer or HIV, where multi-target approaches are standard.
“One of the greatest hopes,” the authors conclude, “is that Alzheimer’s disease will eventually become not just treatable but preventable, through early biomarker screening and intervention in preclinical stages.”
The review is available under a CC BY-NC-ND 4.0 open access license.
Source: Rudman, M.D., Ulrich, J.D., & Holtzman, D.M. “Recent advances in Alzheimer’s disease: From molecular mechanisms to therapeutic strategies.” Cell 189(14), 4193-4224 (2026). DOI: 10.1016/j.cell.2026.06.006