Intraperitoneal radiolabeled OC 125 in patients with advanced ovarian cancer.

Twenty patients with recurrent or persistent epithelial ovarian cancer failing conventional therapies were treated with a single intraperitoneal injection of iodine-131-labeled OC 125 monoclonal antibody. Rare acute side effects were nausea and mild diarrhea. At doses up to 120 mCi of iodine-131, median white blood cell and platelet count nadirs were 3.6k/microliters and 187k/microliters, respectively. Two patients acquired thyroid toxicities despite thyroid blockage with "cold" iodine. One patient had transient TSH elevation while remaining clinically euthyroid, and 1 patient developed activation of a thyroid nodule and clinical hyperthyroidism. Dose-limiting toxicity has not yet been observed. Twelve of 20 patients are alive 3 to 17 months following therapy. Tumor progression was noted in the majority of patients, although 3 patients had documented decreases in tumor burden of short duration. We conclude that, at the doses examined, iodine-131 OC 125 can be safely administered intraperitoneally.