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In Vivo Head-to-Head Comparison of [18F]GTP1 with [18F]MK-6240 and [18F]PI-2620 in Alzheimer Disease
Emily Olafson, Matteo Tonietto, Gregory Klein, Edmond Teng, Andrew Wills Stephens, David Russell, Karen Pickthorn, Sandra M. Sanabria Bohorquez. Journal of Nuclear Medicine, 2025-01-02
Topic: Amyloid, tau and blood-test diagnosis
[18F]GTP1 exhibited retention patterns that correlated with [18F]PI-2620 and [18F]MK-6240 for all Braak regions (except Braak II). Differences in tracer binding in AD target regions were relatively small, and off-target binding profiles were unique to each tracer. Our findings indicate that [18F]GTP1, [18F]PI-2620, and [18F]MK-6240 display similar uptake patterns in AD patients, suggesting that they detect the same tau pathology. However, the tracer-specific off-target signal distribution may impact their direct comparability, and for some use cases, tracer-specific considerations should be taken into account in the development of a standardized harmonization scale for tau PET.
Key findings
- [18F]GTP1 exhibited retention patterns that correlated with [18F]PI-2620 and [18F]MK-6240 for all Braak regions (except Braak II).
- Differences in tracer binding in AD target regions were relatively small, and off-target binding profiles were unique to each tracer.
- Our findings indicate that [18F]GTP1, [18F]PI-2620, and [18F]MK-6240 display similar uptake patterns in AD patients, suggesting that they detect the same tau pathology.
- However, the tracer-specific off-target signal distribution may impact their direct comparability, and for some use cases, tracer-specific considerations should be taken into account in the development of a standardized harmonization scale for tau PET.
Why it matters
This study found that three different tau PET tracers showed similar uptake patterns in Alzheimer's disease patients, suggesting they detect the same tau pathology. However, each tracer had its own pattern of off-target signal, which may affect how directly they can be compared.
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Study details
- Evidence strengthLow
How this study scored 39/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of Nuclear Medicine) |
| Journal's citation record | 2 / 4 | Journal of Nuclear Medicine: journal h-index 230 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” 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 | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 2 / 7 | Cited 8 times (OpenAlex, 2026-10-10) |
| Citations per year | 1 / 5 | 2.7 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 3 / 6 | Cited 4.4× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 1 / 4 | Cited 8 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Sandra M. Sanabria Bohorquez: h-index 32 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Genentech: institution h-index 1,144 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 3 institution(s) in 2 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 39746756) |
| Free to read | 2 / 2 | Free to read |
| Total | 39 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.2967/jnumed.124.268623
- PubMed: 39746756
- Original source →
- Free full text: Journal of Nuclear Medicine →
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 names 8 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
APA 7th
Olafson, E., Tonietto, M., Klein, G., Teng, E., Stephens, A. W., Russell, D., et al. (2025). In Vivo Head-to-Head Comparison of [18F]GTP1 with [18F]MK-6240 and [18F]PI-2620 in Alzheimer Disease. Journal of Nuclear Medicine. https://doi.org/10.2967/jnumed.124.268623
Vancouver
Olafson E, Tonietto M, Klein G, Teng E, Stephens AW, Russell D, et al. In Vivo Head-to-Head Comparison of [18F]GTP1 with [18F]MK-6240 and [18F]PI-2620 in Alzheimer Disease. Journal of Nuclear Medicine. 2025. doi:10.2967/jnumed.124.268623. PMID: 39746756.
BibTeX
@article{olafson2025-39746756,
author = {Olafson, Emily and Tonietto, Matteo and Klein, Gregory and Teng, Edmond and Stephens, Andrew Wills and Russell, David and Pickthorn, Karen and Bohorquez, Sandra M. Sanabria},
title = {{In Vivo Head-to-Head Comparison of [18F]GTP1 with [18F]MK-6240 and [18F]PI-2620 in Alzheimer Disease}},
journal = {Journal of Nuclear Medicine},
year = {2025},
doi = {10.2967/jnumed.124.268623},
pmid = {39746756},
url = {https://doi.org/10.2967/jnumed.124.268623}
}
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