Radioimmunodetection of melanoma utilizing In-111 96.5 monoclonal antibody: a preliminary report.

The murine 96.5 monoclonal antimelanoma antibody (MoAb) was labeled with In-111, and 1-20 mg were administered to 21 patients who had proved or suspected melanoma metastases. One patient was studied twice. In four patients, unlabeled 96.5 MoAb was administered prior to the radiopharmaceutical. All of the patients tolerated the procedure without toxicity regardless of the mass of MoAb administered. The scans were interpreted by two observers, one with full knowledge, the other with no knowledge of the cases. Increasing the MoAb mass or preinfusing unlabeled MoAb prior to the administration of In-111 MoAb resulted in a prolongation of the serum half time, and appeared to improve tumor detection. Lesions were best seen at 72 hours after infusion or later. In all patients who had metastatic disease, at least one tumor site was apparent. Fifty-six per cent of known lesions 1.5 cm or greater in size were detected by the physician who had knowledge of the cases when data from all doses were considered. There wer...