• Nude mice bearing diffuse intraperitoneal carcinomatosis of the human colon cancer cell line LS174T were treated with an anti–carcinoembryonic antigen monoclonal antibody (MAB) that was labeled with yttrium 90 (90Y-ZCE025). Control animals were either untreated or treated with nonspecific99Y-MAB (90Y-96.5c). The median survival (MS) for untreated animals was 26 days. The MS for specific and nonspecific therapy that consisted of 120 μCi of90Y-MAB was 69 and 34 days, respectively. No significant improvement in the MS was observed with a second 120-μCi administration of90Y-MAB given two weeks later. A decreased MS was observed with 80 μCi of90Y-MAB given every four days for three cycles. In each category, specific therapy had a significant advantage over nonspecific therapy in increased effectiveness and decreased toxicity. The90Y-ZCE025 therapy gave an increased life span of almost 200%. The therapeutic effects with different dosing regimens have important implications for treatment planning.
(Arch Surg 1989;124:175-179)