Therapy of peritoneal carcinomatosis of human colon cancer xenografts with yttrium 90-labeled anti-carcinoembryonic antigen antibody ZCE025.

The present study was undertaken to determine whether an anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAB), labeled with the potent beta emitter yttrium 90, could alter the growth of diffuse intraperitoneal carcinomatosis of colon cancer. Nude mice bearing the CEA-producing human tumor line LS174T received therapy with the anti-CEA MAB ZCE025 90Y. Animals were evaluated 12 days after therapy. Untreated animals had a mean (+/- SEM) tumor burden of 3.99 +/- 0.10 g, while animals treated with ZCE025 90Y had 0.29 +/- 0.04 g present. This decrease was significant compared with the 1.31 +/- 0.16 g of tumor present in animals treated with a 90Y-labeled nonspecific antibody 96.5c. The therapeutic effects seen with ZCE025 90Y suggest a potentially useful role for 90Y-labeled anti-CEA MABs in the treatment of gastrointestinal carcinomatosis.