Radioimmunotherapy with Intravenously Administered 131I-Labeled Chimeric Monoclonal Antibody MOvlS in Patients with Ovarian Cancer

We investigated the safety and pharmacokinetics of 131l-labeled chimeric monoclonal antibody MOv18 (131l-c-MOv18 IgG) in patients with ovarian cancer and the estimated radiation dose to cancer-free organs and tumor. Methods: Three patients were injected intravenously with 3 GBq 131l-c-MOv18. Toxicity was evaluated according to the World Health Organization toxicity scales. Blood sampling was performed for 12 wk after injection. Whole-body and SPECT imaging was performed frequently. Dose rates were obtained with a portable dose-rate measure. Quantitative activity analysis of several organs was performed with the region-of-interest technique. Absorbed doses were calculated using MIRDOSE3. Results: Transient changes in hématologieprofiles were seen in 2 patients. Pancytopenia developed in 1 patient; on analysis, she entered the study probably with exhausted bone marrow reserves. Nonhemato-logic toxicity was mild. No human antichimeric antibody re sponses were observed. Mean isolation time was 12 d. The plasma elimination half-life increased almost 3-fold compared with that after tracer doses of c-MOv18. Dosimetry showed mea