Phase I/II study of iodine 125-labeled monoclonal antibody A33 in patients with advanced colon cancer

Abstract

Purpose: A phase I/II study was designed to determine the maximum- tolerated dose (MTD) of iodine 125-labeled monoclonal antibody A33 (125I- mAb A33), its limiting organ toxicity, and the uptake and retention of radioactivity in tumor lesions. Patients and Methods: Patients (N = 21) with advanced chemotherapy-resistant colon cancer who had not received prior radiotherapy were treated with a single 125I-mAb A33 dose. 125I doses were escalated from 50 to 350 mCi/m2 in 50-mCi/m2 increments. Radioimmunoscintigrams were performed for up to 6 weeks after 125I-mAb A33 administration. Results: All 20 patients with radiologic evidence of disease showed localization of 125I to sites of disease. Twelve..