RADIOIMMUNOSCINTIGRAPHY OF RECURRENT, METASTATIC, OR OCCULT COLORECTAL-CANCER WITH TECHNETIUM 99M-LABELED TOTALLY HUMAN MONOCLONAL-ANTIBODY88BV59 - RESULTS OF PIVOTAL, PHASE-III MULTICENTER STUDIES

Purpose: To assess the performance and potential clinical impact of a totally human monoclonal antibody, 88BV59 (HumaSPECT) (INTRACEL, Corp, Rockville, MD), in 202 assessable presurgical patients with recurrent , metastatic, or occult colorectal cancer. Methods: 88BV59, labeled wi th technetium Tc 99m (Tc-99m) (HumaSPECT-Tc), was injected intravenous ly, and planar and single photon emission tomography (SPECT) images we re obtained 14 to 20 hours postinjection. Surgical and pathologic veri fication of tumor were used as the standard against which the performa nce of HumaSPECT-Tc imaging and computed tomography (CT) analysis were evaluated. Results: All patients entered onto the recurrent disease s tudy had at least one tumor site defined on CT. The sensitivity of Hum aSPECT-Tc in those CT-positive patients was 87%, The specificity of Hu maSPECT-Tc was 57% compared with 17% for CT and the difference was sta tistically significant (P < .001). The diagnostic information provided by HumaSPECT-Tc significantly (P < .001) improved the accuracy of the identification of resectable and nonresectable disease over that of C T (80% v 62%). HumaSPECT-Tc scans resulted in a significant (P < .001) reduction versus CT in terms of the proportion of patients understage d (27% v 41%) and overstaged (4% v 26%). In patients with occult disea se (increasing carcinoembryonic antigen [CEA] titer, negative diagnost ic work-up, negative CT), HumaSPECT-Tc correctly identified disease in 15 of 22 (68%) patients. HumaSPECT-Tc images provided additional clin ical data that would have affected patient management decisions in 40 of 202 (19.8%) patients. In 365 patients who received 88BV59, only a s ingle detectable human antihuman antibody (HAHA) response (90 ng/mL) a t 9 weeks postinfusion was observed. Conclusion: HumaSPECT-Tc can prov ide important and accurate information about the presence and location of disease in patients with a high clinical suspicion of metastatic o r recurrent colorectal cancer and either positive (known disease) or n egative (occult disease) CT scans. (C) 1998 by American Society of Cli nical Oncology.