title: Blood pharmacokinetics of various monoclonal antibodies labeled with a new trifunctional chelating reagent for simultaneous conjugation with 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid and biotin before radiolabeling.
abstract: OBJECTIVE
  Knowledge of the blood pharmacokinetics of monoclonal antibodies is crucial in deciding the optimal time for starting the administration of a "clearing agent" or using a "clearing device." The primary purpose was to investigate whether the pharmacokinetics of various antibodies labeled with the same chelator and (111)In differed significantly after i.v. injection in immunocompetent rats. A new trifunctional chelator called "1033" containing a biotin and a radiometal chelation moiety is introduced, making it possible to use only one conjugation procedure for the antibody.
  
  
  METHODS
  Sixty-five non-tumor-bearing rats were included and divided into four groups (I-IV). The blood pharmacokinetics was investigated for rituximab, BR96, and trastuzumab labeled with 1033 and (111)In (I-III). The whole-body activity and activity uptake in muscle, liver, and kidney, which might explain differences in the early pharmacokinetics in blood, were also measured. hMN14 labeled with another chelator [1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)], but with the same radionuclide ((111)In-biotin-DOTA-hMN14), was studied (IV). The blood pharmacokinetics from another 15 tumor-bearing rats was compared with those of non-tumor-bearing rats (III) by injection of (111)In-1033-BR96.
  
  
  RESULTS
  No statistical difference was detected between the groups regarding the blood pharmacokinetics of rituximab, BR96, or trastuzumab. The pharmacokinetics and biodistribution of (111)In-biotin-DOTA-hMN14 exhibited a clear difference compared with others. There were no significant differences in the blood pharmacokinetics of (111)In-1033-BR96 between tumor-bearing rats and non-tumor-bearing rats.
  
  
  CONCLUSIONS
  Different antibodies labeled with the trifunctional chelator 1033 and (111)In did not exhibit different blood pharmacokinetics, which means that the pharmacokinetics could be predicted irrespective of the IgG1 antibody chosen. A small tumor burden did not change the pharmacokinetics of the radioimmunoconjugates.
authors.affiliation: Department of Oncology, Lund University Hospital, Sweden.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Wang
authors.forename: Linda
authors.initials: L
authors.lastname: Mårtensson
authors.forename: Rune
authors.initials: R
authors.lastname: Nilsson
authors.forename: Pär-Ola
authors.initials: PO
authors.lastname: Bendahl
authors.forename: Lars
authors.initials: L
authors.lastname: Lindgren
authors.forename: Tomas
authors.initials: T
authors.lastname: Ohlsson
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Sjögren
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Strand
authors.forename: Jan
authors.initials: J
authors.lastname: Tennvall
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics* / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D058846:Antibodies, Monoclonal, Murine-Derived; D001360:Avidin / Q000737:chemistry; D001710:Biotin / Q000493:pharmacokinetics*; D002614:Chelating Agents / Q000494:pharmacology*; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology; D006573:Heterocyclic Compounds, 1-Ring / Q000493:pharmacokinetics*; D018796:Immunoconjugates / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry; D011786:Quality Control; D016719:Radioimmunodetection; D016499:Radioimmunotherapy / Q000379:methods*; D011868:Radioisotopes / Q000737:chemistry; D051381:Rats; D000069283:Rituximab; D013997:Time Factors; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D058846:Antibodies, Monoclonal, Murine-Derived; C092612:BR96-doxorubicin immunoconjugate; D002614:Chelating Agents; D006573:Heterocyclic Compounds, 1-Ring; D018796:Immunoconjugates; D007074:Immunoglobulin G; D011868:Radioisotopes; D001360:Avidin; C071349:1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid; D000069283:Rituximab; D001710:Biotin; D004317:Doxorubicin; D000068878:Trastuzumab