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

Purpose: More effective intravesical agents are required to limit the recur rence and progression of superficial bladder cancer. This study assessed th e ability of copper-67 (Cu-67)-C595 murine antimucin monoclonal antibody to bind selectively to superficial bladder tumors when administered intravesi cally, with a view to its development for therapy. Patients and Methods: Approximately 20 MBq of Cu-67-C595 monoclonal antibod y was administered intravesically to 16 patients with a clinical indication of superficial bladder cancer. After 1 hour, the bladder was drained and i rrigated. Tissue uptake was assessed by imaging and by the assay of tumor a nd normal tissues obtained by endoscopic resection. Results: 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 ho urs 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). Conclusion: This study indicates a promising method for the treatment of su perficial 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. (C) 2000 by American Society of Clinical Oncology.