On 30 June, an international team of researchers published an article comparing plasma phosphorylated tau assays in Acta Neuropathologica Communications. The study evaluated the performance of the new ALZpath p-Tau217 plasma assay in comparison with two established assays from Lilly: p-Tau217 and p-Tau181. Using samples from 72 participants in the Arizona Study of Aging and Neurodegenerative Disorders, researchers compared plasma biomarker levels with postmortem measures of amyloid plaques and neurofibrillary tangle densities. All three biomarkers showed significant correlations with plaque and tangle pathology. However, Lilly’s p-Tau217 assay showed the strongest associations, particularly with neurofibrillary density scores, even when adjusted for plaque density.
ALZpath’s p-Tau217 assay and Lilly’s p-Tau181 assay had similar performance in predicting Alzheimer’s disease neuropathological change, Braak stage and CERAD plaque scores, with area under the curve scores (AUCs) between 0.74 and 0.79. Lilly’s p-Tau217 assay outperformed both, with AUCs between 0.82 and 0.89. The authors concluded that while ALZpath’s p-Tau217 assay performs similarly to p-Tau181, it is less strongly associated with key pathological features than Lilly’s p-Tau217 assay. Replication in larger, independent samples is recommended. The article has been published open access and can be read here: https://doi.org/10.1186/s40478-025-02064-2