title: Comparison of 211At-PRIT and 211At-RIT of ovarian microtumors in a nude mouse model.
abstract: Abstract Purpose: Pretargeted radioimmunotherapy (PRIT) against intraperitoneal (i.p.) ovarian microtumors using avidin-conjugated monoclonal antibody MX35 (avidin-MX35) and (211)At-labeled, biotinylated, succinylated poly-l-lysine ((211)At-B-PLsuc) was compared with conventional radioimmunotherapy (RIT) using (211)At-labeled MX35 in a nude mouse model.
  
  
  METHODS
  Mice were inoculated i.p. with 1×10(7) NIH:OVCAR-3 cells. After 3 weeks, they received PRIT (1.0 or 1.5 MBq), RIT (0.9 MBq), or no treatment. Concurrently, 10 additional animals were sacrificed and examined to determine disease progression at the start of therapy. Treated animals were analyzed with regard to presence of tumors and ascites (tumor-free fraction; TFF), 8 weeks after therapy.
  
  
  RESULTS
  Tumor status at baseline was advanced: 70% of sacrificed animals exhibited ascites. The TFFs were 0.35 (PRIT 1.0 MBq), 0.45 (PRIT 1.5 MBq), and 0.45 (RIT). The 1.5-MBq PRIT group exhibited lower incidence of ascites and fewer tumors >1 mm than RIT-treated animals.
  
  
  CONCLUSIONS
  PRIT was as effective as RIT with regard to TFF; however, the size distribution of tumors and presence of ascites indicated that 1.5-MBq PRIT was more efficient. Despite advanced disease in many animals at the time of treatment, PRIT demonstrated good potential to treat disseminated ovarian cancer.
authors.affiliation: Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. sofia.frost@radfys.gu.se
authors.forename: Sofia H L
authors.initials: SH
authors.lastname: Frost
authors.forename: Tom
authors.initials: T
authors.lastname: Bäck
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chouin
authors.forename: Ragnar
authors.initials: R
authors.lastname: Hultborn
authors.forename: Lars
authors.initials: L
authors.lastname: Jacobsson
authors.forename: Jörgen
authors.initials: J
authors.lastname: Elgqvist
authors.forename: Holger
authors.initials: H
authors.lastname: Jensen
authors.forename: Per
authors.initials: P
authors.lastname: Albertsson
authors.forename: Sture
authors.initials: S
authors.lastname: Lindegren
mesh_terms: D000512:Alpha Particles / Q000627:therapeutic use*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001246:Astatine / Q000008:administration & dosage*; D001360:Avidin / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging / Q000276:immunology / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D011877:Radionuclide Imaging; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D001360:Avidin; D001246:Astatine