Immunoscintigraphy of prostatic cancer: preliminary results with 111In-labeled monoclonal antibody 7E11-C5.3 (CYT-356)

Prostate. 1991;18(3):229-41. doi: 10.1002/pros.2990180305.


A phase 1 study was conducted with the investigational immunoscintigraphic agent, 111In-CYT-356, a radiolabeled, site-specific immunoconjugate of monoclonal antibody 7E11-C5.3, in 40 patients with prostatic carcinoma and known distant metastases. Each patient received a single intravenous infusion of CYT-356 (dose range, 0.1-5 mg) radiolabeled with approximately 5 mCi of 111In. None of the patients experienced adverse reactions. One patient who received a 5-mg dose developed antibodies to the CYT-356 immunoconjugate. 111In-CYT-356 immunoscintigraphy detected bony metastases in 21 of 38 patients (55%), including 12 of 14 (86%) receiving concomitant hormonal therapy, and soft tissue lesions in four of six patients (67%). Antibody imaging detected occult lesions in the bony pelvis and lumbar spine, which were confirmed by follow-up imaging tests, in one patient. Higher CYT-356 doses may clear the blood pool more slowly. These results suggest that 111In-CYT-356 can be safely administered to patients with prostatic carcinoma and that further clinical investigation of this agent is warranted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antibodies, Monoclonal*
  • Humans
  • Indium Radioisotopes*
  • Male
  • Prostatic Neoplasms / diagnostic imaging*
  • Radionuclide Imaging


  • Antibodies, Monoclonal
  • Indium Radioisotopes