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

Abstract

The murine 96.5 monoclonal antimelanoma antibody (MoAb) was labeled with 111In and 1-20 mg were administered to 21 patients who had proved or suspected melanoma metastases. One patient was studied twice. In 4 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 2-observers, 1 with full knowledge, the other with no knowledge of the cases. Increasing the MoAb mass or preinfusing unlabeled MoAb prior to the administration 111In MoAb resulted in a prolongation of the serum half time, and appeared to improve tumor detection. Lesions were best seen at 72 h after infusion or later. In all patients who had metastatic disease, at least 1 tumor site was apparent. Of known lesions 1.5 cm or greater in size, 56% were detected by the physician who had knowledge of the cases when data from all doses were considered. There were 8 lesions detected that were not suspected in the workup of the patient. When these are included, the detection rate rises to 61%. Forty-nine percent were detected by the other physician. Subtraction techniques were not employed. Lesions were often better seen with single photon emission computed tomography than with planar imaging techniques. The 96.5 111In MoAb appears to have utility for the detection of metastatic melanoma. Further clinical evaluation of 96.5 111In MoAb is warranted.