Effect of unlabelled monoclonal antibody (MoAb) on biodistribution of 111indium labelled (MoAb).
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.
Lamki
L M
LM
Department of Nuclear Medicine, University of Texas M. D. Anderson Hospital and Tumor Institute, Houston 77030.
Murray
J L
JL
Rosenblum
M G
MG
Patt
Y Z
YZ
Babaian
R
R
Unger
M W
MW
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
D000911:Antibodies, Monoclonal; D007205:Indium Radioisotopes