Targeting superficial bladder cancer by the intravesical administration of copper-67-labeled anti-MUC1 mucin monoclonal antibody C595.

Abstract

More effective intravesical agents are required to limit the recurrence and progression of superficial bladder cancer. This study assessed the ability of copper-67 ((67)Cu)-C595 murine antimucin monoclonal antibody to bind selectively to superficial bladder tumors when administered intravesically, with a view to its development for therapy. Approximately 20 MBq of (67)Cu-C595 monoclonal antibody was administered intravesically to 16 patients with a clinical indication of superficial bladder cancer. After 1 hour, the bladder was drained and irrigated. Tissue uptake was assessed by imaging and by the assay of tumor and normal tissues obtained by endoscopic resection. Tumor was correctly identified in the images of 12 of 15 patients who were subsequently found to have tumors. Assay of biopsy samples at 2 hours showed a mean tumor uptake of 59.4% of the injected dose per kilogram (SD = 48.0), with a tumor-to-normal tissue ratio of 14.6:1 (SD = 20). After 24 hours (n = 5), this decreased to 4.3% of the injected dose per kilogram (SD = 2.9), with a tumor-to-normal tissue ratio of 1.8:1 (SD = 0.8). This study indicates a promising method for the treatment of superficial bladder cancer. Although the mean initial tumor uptake was high, effective therapy of bladder tumors will require an increased retention of the cytotoxic radionuclide in tumor tissue.