Biodistribution, pharmacokinetics and imaging of 131I-labelled OC125 in ovarian cancer.

Fifteen patients with or suspected of having ovarian carcinoma were injected intravenously (i.v.) or intraperitoneally (i.p.) with 131I-labelled OC125 F(ab')2. Radioimmunoscintigraphy after i.v. injection revealed 50% of the tumor sites. After i.p. injection all tumor sites were visualized, except in one case in which the antibody remained loculated because of adhesions. One patient with endometrial cancer showed no specific uptake of the antibody after i.p. injection. The serum half-life of the radiolabelled antibody after i.v. injection was 30 hr. After i.p. injection there was a slow appearance of radiolabelled antibody in the blood with a maximum level of 1.4% dose per liter at 24 hr after injection. Urinary excretion of the radiolabel was the same for both routes of administration, with 50% of the dose excreted in approximately 48 hr. Tumor uptake was slightly higher after i.p. injection. Liver and bone marrow uptake after i.p. injection were one-half of the uptake after i.v. injection.