Tumour dosimetry across 6 cycles of [177Lu]Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer: results from the VISION sub-study
Bibliographic record
Abstract
Ziel/Aim: In VISION, [ 177 Lu]Lu-PSMA-617 ( 177 Lu-PSMA-617) plus standard of care (SoC) significantly improved overall survival and radiographic progression-free survival in patients (pts) with PSMA-positive metastatic castration-resistant prostate cancer. In the VISION dosimetry sub-study, 177 Lu-PSMA-617 had a good safety profile with low radiotoxicity. Here, we present the tumor dosimetry for 177 Lu-PSMA-617 across cycles 1-6. Methodik/Methods: Dosimetry was assessed in a separate cohort of 29 non-randomized pts. Pts received 177 Lu-PSMA-617 (7.4 GBq/6 weeks,≤6 cycles) plus SoC. Pts underwent SPECT/CT scans during cycle 1 at around 2, 26, 48 and 168 h after 177 Lu-PSMA-617 injection, and in subsequent cycles at 36-48 h post-injection. Region of interest/volume of interest construction was performed on PET/CT images (cycle 1) and SPECT/CT (kinetic data) images (cycles 2-6) to determine tumor volumes and morphology. Pts with≥1 evaluable tumor in cycles 2-6 after selection of≥5 tumors per pt in cycle 1 were included. The normalized disintegration numbers were calculated assuming consistent uptake and retention half-times across cycles, with only variations in activity uptake magnitude. The ratio of individual tumor activities in each cycle to cycle 1 was used to scale the normalized disintegrations from cycle 1 to following cycles. Tumor dosimetry parameters were estimated using the standard MIRD/RADAR method. Ergebnisse/Results: In total, 60 unique, delineated prostate cancer tumors were analyzed across cycles 1-6, in 18 patients who had evaluable tumors in cycles 2-6. The mean radiation-absorbed dose for all tumors declined from 7.9 Gy/GBq (SD 10; range 0.17-55) in cycle 1 (60 tumors) to 1.6 Gy/GBq (SD 1.7; range 0.11-7.5) in cycle 6 (20 tumors). For tumors in bone, the mean absorbed dose was 6.4 Gy/GBq (SD 7.3; range 0.17-45) in cycle 1 (46 tumors) and 1.3 Gy/GBq (SD 0.95; range 0.11-3.9) in cycle 6 (17 tumors). For tumors in lymphatic tissue, the mean absorbed dose was 11 Gy/GBq (SD 15; range 0.99-55) in cycle 1 (12 tumors) and 3.2 Gy/GBq (SD 3.8; range 0.14-7.5) in cycle 6 (3 tumors). In total pts received a median 6-cycle cumulative absorbed dose of ~ 100 Gy. Schlussfolgerungen/Conclusion: Declining radiation-absorbed doses across cycles 1-6 in this sub-study were consistent with the anti-tumor efficacy of 177 Lu-PSMA-617 observed in VISION. Publication History Article published online: 12 March 2025 © 2025. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".