title: Effect of unlabelled monoclonal antibody (MoAb) on biodistribution of 111indium labelled (MoAb).
abstract: We have evaluated immunoscintigraphy in cancer patients using four 111In-labelled murine monoclonal antibodies (MoAb): 96.5 (anti-P97 of melanoma), ZME-018 (anti-high molecular weight antibody of melanoma), ZCE-025 (anti-CEA for colon cancer) and PAY-276 (anti-prostatic acid phosphatase for prostatic cancer). The effect of increasing the doses of unlabelled MoAb (co-infused with 1 mg labelled MoAb) on the relative body distribution of each labelled MoAb was assessed. Localization in the liver decreased significantly in all cases, with increasing MoAb dose, except for ZME-018. Localization in other organs increased significantly as the liver activity decreased. The spleen activity, however, fell in the case of MoAb ZME-018. Blood-pool activity increased with MoAb dose in all four MoAbs. These findings correlated with the rise in the detection rate of metastases, the plasma half-life, and other pharmacokinetic parameters. However, the dose level at which this correlation occurred varied with each antibody. These data demonstrate that co-infusion of unlabelled MoAb with 111In-labelled MoAb could alter the organ distribution, pharmacokinetics and tumour uptake in a favourable manner, though the degree to which this occurs depends on the antibody in question.
authors.affiliation: Department of Nuclear Medicine, University of Texas M. D. Anderson Hospital and Tumor Institute, Houston 77030.
authors.forename: L M
authors.initials: LM
authors.lastname: Lamki
authors.forename: J L
authors.initials: JL
authors.lastname: Murray
authors.forename: M G
authors.initials: MG
authors.lastname: Rosenblum
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Patt
authors.forename: R
authors.initials: R
authors.lastname: Babaian
authors.forename: M W
authors.initials: MW
authors.lastname: Unger
mesh_terms: D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D006801:Humans; D007205:Indium Radioisotopes; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging / Q000556:secondary; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D011877:Radionuclide Imaging; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D007205:Indium Radioisotopes