title: Advantage of lutetium-177 versus radioiodine immunoconjugate in targeted radionuclide therapy of b-cell tumors.
abstract: BACKGROUND
  We herein report a comparison of the radiolabels 177Lu and 125I bound to the monoclonal antibody HH1 that targets the CD37 antigen expressed on non-Hodgkin B-cell lymphomas.
  
  
  METHODS
  Mixtures of 177Lu and 125I-labeled HH1 antibody were co-injected into nude mice carrying Ramos xenografts and the biodistribution using the paired label format allowing tracer comparisons in each individual mouse.
  
  
  RESULTS
  Products of the two radionuclides had very similar immunoractivity in vitro but showed different properties in vivo. Both products had relevant stability in blood and most normal tissues in nude mice carrying subcutaneous Ramos xenografts. However, both the tumor uptake and retention were significantly higher for 177Lu vs. 125I labeled HH1. The tumor to normal tissue ratios were several-fold improved for 177Lu compared to radioiodine labeled antibodies.
  
  
  CONCLUSIONS
  The data presented herein support the evaluation of CD37 as a target for clinical 177Lu-based radioimmunotherapy against b-cell malignancies.
authors: Nordic Nanovector AS, Oslo, Norway Norwegian Radium Hospital, Oslo University Hospital, Montebello, Norway.
authors: Ada
authors: A
authors: Repetto-Llamazares
authors: Nordic Nanovector AS, Oslo, Norway Norwegian Radium Hospital, Oslo University Hospital, Montebello, Norway.
authors: Nasir
authors: N
authors: Abbas
authors: Norwegian Radium Hospital, Oslo University Hospital, Montebello, Norway Institute of Clinical Medicine, University of Oslo, Blindern, Norway.
authors: Øyvind S
authors: ØS
authors: Bruland
authors: Nordic Nanovector AS, Oslo, Norway.
authors: Jostein
authors: J
authors: Dahle
authors: Nordic Nanovector AS, Oslo, Norway royhlars1@yahoo.no.
authors: Roy H
authors: RH
authors: Larsen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000493:pharmacokinetics / Q000494:pharmacology; D000951:Antigens, Neoplasm / Q000276:immunology; D005260:Female; D006573:Heterocyclic Compounds, 1-Ring / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D000922:Immunotoxins / Q000493:pharmacokinetics / Q000494:pharmacology*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000494:pharmacology*; D008187:Lutetium / Q000493:pharmacokinetics / Q000494:pharmacology*; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000378:metabolism / Q000532:radiotherapy*; D051379:Mice; D008819:Mice, Nude; D058990:Molecular Targeted Therapy; D016499:Radioimmunotherapy / Q000379:methods; D011868:Radioisotopes / Q000493:pharmacokinetics / Q000494:pharmacology*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000494:pharmacology*; D059470:Tetraspanins / Q000276:immunology; D014018:Tissue Distribution; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; C059071:CD37 protein, human; D006573:Heterocyclic Compounds, 1-Ring; D000922:Immunotoxins; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D059470:Tetraspanins; C071349:1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid; D008187:Lutetium
keywords: 177Lu; non-Hodgkin lymphoma; radioimmunotherapy