Development of a 124I-labeled version of the anti-PSMA monoclonal antibody capromab for immunoPET staging of prostate cancer: Aspects of labeling chemistry and biodistribution

Vladimir Tolmachev, Jennie Malmberg, Sergio Estrada, Olof Eriksson, Anna Orlova

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Correct staging of prostate cancer is an unmet clinical need. Radionuclide targeting of prostate-specific membrane antigen (PSMA) with 111In- labeled capromab pendetide (ProstaScint) is a clinical option for prostate cancer staging. We propose the use of 124I-labeled capromab to decrease the retention of radioactivity in healthy organs (due to the non-residualizing properties of the radiolabel). The use of 124I as a label should increase imaging sensitivity due to the advantages of PET as an imaging modality. Capromab targets the intracellular domain of PSMA; accumulation of radioactivity in the tumor should not depend on internalization of the antigen/antibody complex. Capromab was iodinated, and its targeting properties were compared with indium labeled counterpart in LNCaP xenografts in dual isotope mode. PSMA-negative xenografts (PC3) were used as a negative control. Radioiodinated capromab bound to PSMA specifically. Biodistribution of 125I/111In-capromab showed a more rapid clearance of iodine radioactivity from liver, spleen, kidneys, bones, colon tissue, as well as tumors. Maximum tumor uptake (13±8% ID/g for iodine and 29±9% ID/g for indium) and tumor-to-non-tumor ratios for both agents were measured 5 days post-injection (pi). High tumor accumulation and low uptake of radioactivity in normal organs were confirmed using microPET/CT 5 days pi of 124I-capromab.

Original languageEnglish
Pages (from-to)1998-2008
Number of pages11
JournalInternational Journal of Oncology
Volume45
Issue number6
DOIs
Publication statusPublished - Jun 2014
Externally publishedYes

Keywords

  • Iodine-124
  • Molecular imaging
  • PET
  • Prostate cancer
  • Prostate-specific membrane antigen

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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