The biodistribution and pharmacokinetics of 2
monoclonal antibodies (MAbs) specific for ovarian
carcinoma, OC125 and OV-TL3, were studied in nude mice bearing intraperitoneally (i.p.) growing human ovarian
carcinoma xenografts of NIH:OVCAR-3. The ovarian
carcinoma xenografts grew as non-adherent cells in
ascites and as solid implants in the peritoneal cavity of injected mice. The biodistribution and pharmacokinetics were determined by measurement of radioactivity in
tumor masses,
ascites, blood and other tissues after intravenous (i.v.) and i.p. injection of radioiodinated F(ab')2 fragments of MAbs. The specificity of the observed
tumor localization was then evaluated by comparing the uptake of the anti-ovarian
carcinoma antibodies OC125 and OV-TL3 with the uptake of a radioiodinated non-ovarian
carcinoma-specific MAb A2C6. The results of the study indicate that uptake of the anti-ovarian
carcinoma antibodies was highest in the non-adherent
tumor cells in the
ascites after i.p. injection. The observed uptake was 85% injected dose/g for OV-TL3 and 22% injected dose/g for OC125. This compares to the observed antibody uptake of 9% injected dose/g for OV-TL3 and less than 1% injected dose/g for OC125 in solid
tumor masses after i.p. injection. After i.v. injection, uptake of OC125 and OV-TL3 was less than 3% injected dose/g, both for nonadherent
tumor cells and for solid
tumor masses. The data support the conclusion that OV-TL3 is superior to OC125 and that i.p. administration of radiolabelled MAb F(ab')2 fragments is superior to their i.v. administration for
immunotherapy of ovarian
carcinoma.