title: Bispecific antibody complex pre-targeting and targeted delivery of polymer drug conjugates for imaging and therapy in dual human mammary cancer xenografts: targeted polymer drug conjugates for cancer diagnosis and therapy.
abstract: BACKGROUND
  Doxorubicin, a frontline chemotherapeutic agent, limited by its cardiotoxicity and other tissue toxicities, was conjugated to N-terminal DTPA-modified polyglutamic acid (D-Dox-PGA) to produce polymer pro-drug conjugates. D-Dox-PGA or Tc-99 m labeled DTPA-succinyl-polylysine polymers (DSPL) were targeted to HER2-positive human mammary carcinoma (BT-474) in a double xenografted SCID mouse model also hosting HER2-negative human mammary carcinoma (BT-20).
  
  
  METHODS
  After pretargeting with bispecific anti-HER2-affibody-anti-DTPA-Fab complexes (BAAC), anti-DTPA-Fab or only phosphate buffered saline, D-Dox-PGA or Tc-99 m DSPL were administered. Positive therapeutic control mice were injected with Dox alone at maximum tolerated dose (MTD).
  
  
  RESULTS
  Only BT-474 lesions were visualized by gamma imaging with Tc-99 m-DSPL; BT-20 lesions were not. Therapeutic efficacy was equivalent in mice pretargeted with BAAC/targeted with D-Dox-PGA to mice treated only with doxorubicin. There was no total body weight (TBW) loss at three times the doxorubicin equivalent MTD with D-Dox-PGA, whereas mice treated with doxorubicin lost 10% of TBW at 2 weeks and 16% after the second MTD injection leading to death of all mice.
  
  
  CONCLUSIONS
  Our cancer imaging and pretargeted therapeutic approaches are highly target specific, delivering very high specific activity reagents that may result in the development of a novel theranostic application. HER/2 neu specific affibody-anti-DTPA-Fab bispecific antibody pretargeting of HER2 positive human mammary xenografts enabled exquisite targeting of polymers loaded with radioisotopes for molecular imaging and doxorubicin for effective therapy without the associating non-tumor normal tissue toxicities.
authors.affiliation: Department of Pharmaceutical Sciences, Bouve College of Health Sciences, School of Pharmacy, Northeastern University, 140 The Fenway, Rm X138, 130 Huntington Ave, Boston, MA, 02115, USA, b.khaw@neu.edu.
authors.forename: Ban-An
authors.initials: BA
authors.lastname: Khaw
authors.forename: Keyur S
authors.initials: KS
authors.lastname: Gada
authors.forename: Vishwesh
authors.initials: V
authors.lastname: Patil
authors.forename: Rajiv
authors.initials: R
authors.lastname: Panwar
authors.forename: Savitri
authors.initials: S
authors.lastname: Mandapati
authors.forename: Arash
authors.initials: A
authors.lastname: Hatefi
authors.forename: Stan
authors.initials: S
authors.lastname: Majewski
authors.forename: Andrew
authors.initials: A
authors.lastname: Weisenberger
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use; D004337:Drug Carriers / Q000737:chemistry; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D051379:Mice; D016513:Mice, SCID; D004369:Pentetic Acid / Q000737:chemistry; D011099:Polyglutamic Acid / Q000737:chemistry; D016499:Radioimmunotherapy; D011877:Radionuclide Imaging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D013667:Technetium / Q000627:therapeutic use; D014018:Tissue Distribution; D023041:Xenograft Model Antitumor Assays
chemical_list: D018033:Antibodies, Bispecific; D004317:Doxorubicin; D004337:Drug Carriers; D004369:Pentetic Acid; D011099:Polyglutamic Acid; D018719:Erb-b2 Receptor Tyrosine Kinases; D013667:Technetium