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Evaluating Plasma p-tau217 as an Endpoint for Alzheimer Disease Clinical Trials
Pâmela C.L. Ferreira, Bruna Bellaver, Guilherme Povala, Guilherme Bauer‐Negrini, Cristiano Schaffer Aguzzoli, João Pedro Ferrari‐Souza, Douglas Teixeira Leffa, Carolina Soares et al.. Neurology, 2025-12-09
Topic: Amyloid, tau and blood-test diagnosis
A total of 716 individuals were included in the analysis: 413 cognitively unimpaired (CU) participants (58.6% female; mean age = 70.6 years, SD = 7.9) and 303 cognitively impaired (CI) participants (54.7% female; mean age = 73.2 years, SD = 7.4). In Aβ-positive individuals, the annual rate of change in plasma p-tau217 was similar between CU (0.07 pg/mL/y, SD = 0.11) and CI (0.08 pg/mL/y, SD = 0.13) groups. Effect size was 0.64 and 0.62 in CU and CI Aβ-positive individuals, respectively. The minimum sample size required per study group to detect a 25% drug effect was 610 for the CU Aβ-positive and 664 for the CI Aβ-positive group. Notably, selecting individuals with intermediate Aβ levels (Centiloid 20-40) yielded higher effect sizes (CU: 0.85; CI: 0.72), which reduced the required sample sizes per study group to 342 for CU and 492 for CI. Our findings support that changes in plasma p-tau217 represent a robust endpoint for clinical trials targeting CU or CI individuals with Aβ pathology.
Key findings
- A total of 716 individuals were included in the analysis: 413 cognitively unimpaired (CU) participants (58.6% female; mean age = 70.6 years, SD = 7.9) and 303 cognitively impaired (CI) participants (54.7% female; mean age = 73.2 years, SD = 7.4).
- In Aβ-positive individuals, the annual rate of change in plasma p-tau217 was similar between CU (0.07 pg/mL/y, SD = 0.11) and CI (0.08 pg/mL/y, SD = 0.13) groups.
- Effect size was 0.64 and 0.62 in CU and CI Aβ-positive individuals, respectively.
- The minimum sample size required per study group to detect a 25% drug effect was 610 for the CU Aβ-positive and 664 for the CI Aβ-positive group.
- Notably, selecting individuals with intermediate Aβ levels (Centiloid 20-40) yielded higher effect sizes (CU: 0.85; CI: 0.72), which reduced the required sample sizes per study group to 342 for CU and 492 for CI.
Why it matters
This analysis of 716 people found that changes in plasma p-tau217 over time were similar in cognitively unimpaired and cognitively impaired individuals with amyloid pathology, and it could serve as an endpoint in clinical trials. Selecting people with intermediate amyloid levels reduced the sample sizes needed to detect a drug effect.
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Study details
- Study designlongitudinal study
- Participants716
- Effect size58.6%; 54.7%
- Evidence strengthModerate
How this study scored 68/100
Published in a leading specialty journal, and it is a longitudinal study following the same people over time. Scored zero for randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | 4 / 4 | Neurology: journal h-index 525 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 2 / 4 | 716 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 3 / 7 | Cited 15 times (OpenAlex, 2026-10-10) |
| Citations per year | 2 / 5 | 5.0 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 4 / 6 | Cited 9.5× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 1 / 6 | Cited by 2 other studies in this library |
| Still being cited | 2 / 4 | Cited 15 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Tharick Ali Pascoal: h-index 61 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of California, San Francisco: institution h-index 1,915 (OpenAlex) |
| Multi-centre collaboration | 3 / 3 | OpenAlex lists 10 institution(s) in 4 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 41364889) |
| Free to read | 2 / 2 | Free to read |
| Total | 68 / 100 | — |
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Read the original
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Ferreira, P. C., Bellaver, B., Povala, G., Bauer‐Negrini, G., Aguzzoli, C. S., Ferrari‐Souza, J. P., et al. (2025). Evaluating Plasma p-tau217 as an Endpoint for Alzheimer Disease Clinical Trials. Neurology. https://doi.org/10.1212/wnl.0000000000214441
Vancouver
Ferreira PC, Bellaver B, Povala G, Bauer‐Negrini G, Aguzzoli CS, Ferrari‐Souza JP, et al. Evaluating Plasma p-tau217 as an Endpoint for Alzheimer Disease Clinical Trials. Neurology. 2025. doi:10.1212/wnl.0000000000214441. PMID: 41364889.
BibTeX
@article{ferreira2025-41364889,
author = {Ferreira, Pâmela C.L. and Bellaver, Bruna and Povala, Guilherme and Bauer‐Negrini, Guilherme and Aguzzoli, Cristiano Schaffer and Ferrari‐Souza, João Pedro and Leffa, Douglas Teixeira and Soares, Carolina and others},
title = {{Evaluating Plasma p-tau217 as an Endpoint for Alzheimer Disease Clinical Trials}},
journal = {Neurology},
year = {2025},
doi = {10.1212/wnl.0000000000214441},
pmid = {41364889},
url = {https://doi.org/10.1212/wnl.0000000000214441}
}
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