Nuclear Medicine and Biology
Volumes 106–107, March–April 2022, Pages 21-28
Radiolabeling of PSMA-617 with 89Zr: A novel use of DMSO to improve radiochemical yield and preliminary small-animal PET results
Author links open overlay panelRyotaImuraabcYoshitakaKumakurae
doi.org/10.1016/j.nucmedbio...
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Highlights
•89Zr-PSMA-617 was achieved for the first time by using a HEPES buffer with DMSO.
•89Zr-PSMA-617 allowed visualization of PSMA-positive tumors.
•The radiolabel did not accumulate in the bladder at 24 h post-injection.
•89Zr-PSMA-617 could be an optimum choice for dosimetry of 177Lu-PSMA-617.
abstract
Introduction
Novel diagnostic and therapeutic options are urgently needed for patients with metastatic castration-resistant prostate cancer (CRPC). PSMA-617 is one of the most promising ligands that bind to prostate specific membrane antigen (PSMA), the cell surface biomarker of CRPC. Of the radiolabeled PSMA ligands developed to date, [68Ga]Ga-PSMA-617 is most commonly used for PSMA positron emission tomography (PET) prior to radioligand therapy (RLT) with [177Lu]Lu-PSMA-617. However, the presence of 68Ga radioactivity (half-life 68 m) in urine at the early PET imaging time point complicates optimization of the therapeutic dose of PSMA-617 labeled with 177Lu (half-life 6.7 d). Thus, PET imaging with the long-lived positron emitter 89Zr (half-life 3.3 d) would be better suited in order to optimize the dose of [177Lu]Lu-PSMA-617 as 89Zr PET allows scans after excretion of the radioactive urine. Until now, PSMA -617 could not be radiolabeled with 89Zr with high radiochemical yield due to poor incorporation of 89Zr into 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Here we report a novel method for radiolabeling PSMA-617 with 89Zr and the preliminary results of small-animal PET with [89Zr]Zr-PSMA-617.