Kidney absorbed radiation doses for [177Lu]Lu-PSMA-617 and [177Lu]Lu-PSMA-I&T determined by 3D clinical dosimetry. Issue 4 (4th April 2023)

• Record Type: Journal Article
• Authors: Uijen, Maike J.M.; Privé, Bastiaan M.; van Herpen, Carla M.L.; Westdorp, Harm; van Gemert, Willemijn A.; de Bakker, Maarten; Gotthardt, Martin; Konijnenberg, Mark W.; Peters, Steffie M.B.; Nagarajah, James
• Is Part Of: Nuclear medicine communications. Volume 44:Issue 4(2023)
• Page Start: 270
• Page End: 275
• Publication Date: 2023-04-04
• Subjects: dosimetry -- [177Lu]Lu-PSMA -- prostate-specific membrane antigen (PSMA) -- radioligand therapy -- SPECT imaging; Nuclear medicine -- Periodicals; 616.07575
• DOI: 10.1097/MNM.0000000000001658
• Languages: English
• ISSNs: 0143-3636

Abstract

Abstract : Purpose: For prostate-specific membrane antigen-directed radioligand therapy (PSMA-RLT), [ 177 Lu]Lu-PSMA-617 and [ 177 Lu]Lu-PSMA-I&T are the currently preferred compounds. Recent preclinical studies suggested ~30x higher kidney absorbed dose for [ 177 Lu]Lu-PSMA-I&T compared to [ 177 Lu]Lu-PSMA-617, which may lead to an increased risk of kidney toxicity. We performed two single-centre, prospective dosimetry studies with either [ 177 Lu]Lu-PSMA-617 or [ 177 Lu]Lu-PSMA-I&T, using an identical dosimetry protocol. We evaluated the absorbed doses of both 177 Lu-labelled radioligands in human kidneys. Methods: 3D SPECT/computed tomography (CT) imaging of the kidneys was performed after PSMA-RLT in cancer patients with PSMA-positive disease and an adequate glomerular filtration rate (≥50 mL/min). Ten metastatic hormone-sensitive prostate cancer patients (mHSPC) were treated with [ 177 Lu]Lu-PSMA-617 and 10 advanced salivary gland cancer (SGC) patients were treated with [ 177 Lu]Lu-PSMA-I&T. SPECT/CT imaging was performed at five timepoints (1 h, 24 h, 48 h, 72 h, and 168 h post-injection). In mHSPC patients, SPECT/CT imaging was performed after cycles 1 and 2 (cumulative activity: 9 GBq) and in SGC patients only after cycle 1 (activity: 7.4 GBq). Kidney absorbed dose was calculated using organ-based dosimetry. Results: The median kidney absorbed dose was 0.49 Gy/GBq (range: 0.34–0.66) and 0.73 Gy/GBq (range: 0.42–1.31) for [ 177 Lu]Lu-PSMA-617 and [ 177 Lu]Lu-PSMA-I&T, respectively (independent samples t test; P = 0.010). Conclusion: This study shows that the kidney absorbed dose for [ 177 Lu]Lu-PSMA-617 and [ 177 Lu]Lu-PSMA-I&T differs, with a ~1.5x higher median kidney absorbed dose for [ 177 Lu]Lu-PSMA-I&T. This difference in the clinical setting is considerably smaller than observed in preclinical studies and may not hamper treatments with [ 177 Lu]Lu-PSMA-I&T.