RADIOIMMUNOSCINTIGRAPHY OF COLORECTAL-CARCINOMA USING TC-99M-LABELED,TOTALLY HUMAN MONOCLONAL-ANTIBODY 88BV59H21-21

Radioimmunoscintigraphy (RIS) using human monoclonal antibodies offers the important clinical advantage of repeated imaging over murine mono clonal antibodies by eliminating the cross-species antibody response. This article reports a Phase I-II clinical trial with Tc-99m-labeled, totally human monoclonal antibody 88BV59H21-2 in patients with colorec tal carcinoma. The study population consisted of 34 patients with colo rectal cancer (20 men and 14 women; age range, 44-81 years), Patients were administered 5-10 mg antibody labeled with 21-41 mCi Tc-99m by th e i,v. route and imaged at 3-10 and 16-24 h after infusion using plana r and single-photon emission computed tomographic (CT) techniques, Pat hological confirmation was obtained in 25 patients who underwent surge ry. Human antihuman antibody (HAHA) titers were checked prior to and 1 and 3 months after the infusion. RIS with Tc-99m-labeled 88BV59H21-2 revealed a better detection rate in the abdomen-pelvis region compared with axial CT, The combined use of both modalities increased the sens itivity in both the liver and abdomen-pelvis regions, Ten patients dev eloped mild adverse reactions (chills and fever), No HAHA response was detected in this series. Tc-99m-labeled human monoclonal antibody 88B V59H21-2 RIS shows promise as a useful diagnostic modality in patients with colorectal cancer, RIS alone or in combination with CT is more s ensitive than CT in detecting tumor within the abdomen and pelvis, Rep eated RIS studies may be possible, due to the lack of a HAHA response.