Radioimmunodetection of melanoma utilizing In-111 96.5 monoclonal antibody: a preliminary report.

Abstract

The murine 96.5 monoclonal antimelanoma antibody (MoAb) was labeled with In-111, and 1-20 mg were administered to 21 patients who had proved or suspected melanoma metastases. One patient was studied twice. In four patients, unlabeled 96.5 MoAb was administered prior to the radiopharmaceutical. All of the patients tolerated the procedure without toxicity regardless of the mass of MoAb administered. The scans were interpreted by two observers, one with full knowledge, the other with no knowledge of the cases. Increasing the MoAb mass or preinfusing unlabeled MoAb prior to the administration of In-111 MoAb resulted in a prolongation of the serum half time, and appeared to improve tumor detection. Lesions were best seen at 72 hours after infusion or later. In all patients who had metastatic disease, at least one tumor site was apparent. Fifty-six per cent of known lesions 1.5 cm or greater in size were detected by the physician who had knowledge of the cases when data from all doses were considered. There were eight lesions detected that were not suspected in the workup of the patient. When these are included, the detection rate rises to 61%. Forty-nine per cent were detected by the other physician. Subtraction techniques were not employed. Lesions were often better seen with single photon emission computed tomography than with planar imaging techniques. The 96.5 In-111 MoAb appears to have utility for the detection of metastatic melanoma. Further clinical evaluation of 96.5 In-111 MoAb is warranted.

The effect of circulating antigen and radiolabel stability on the biodistribution of an indium labelled antibody

“…This finding contrasts with those of previous studies where it was concluded that administration of cold antibody was beneficial. The earlier studies, however, claimed an improvement only in the number of tumour deposits localised in patients with multiple tumours and have not demonstrated increased tumour uptake of radioactivity (Halpern et al, 1985;Murray et al, 1985;Carrasquillo et al, 1986).…”

“…Although it has been suggested by some authors that the presence of antigen in the blood does not significantly affect the results of imaging (Goldenberg et of tumour sites detected on immunoscintigraphy is increased (Halpern et al, 1985;Murray et al, 1985;Carrasquillo et al, 1986). This conflict of opinion on the significant of circulating immune complexes may be explained by differences in the antigen associated with the tumour and those present in the circulation and also in their affinity of binding to administered radiolabelled antibody.…”

Detection of colorectal carcinoma by emission-computerized tomography after injection of 123I-labeled Fab or F(ab')2 fragments from monoclonal anti-carcinoembryonic antigen antibodies.

“…When "'In-labeled antibodies have been injected into patients, however, a very high nonspecific uptake has always been observed in the reticuloendothelium, especially in the liver (26,38), even when the DTPA coupling was performed under mild conditions (25,39). Since high nonspecific liver uptake may interfere with the detection of liver metastases, we considered this label not to be optimal for the evaluation of colon carcinoma patients by immunoscintigraphy.…”

Evaluation of a technique for the intraoperative detection of a radiolabelled monoclonal antibody against colorectal cancer

“…Absolute tumour antibody uptake has been determined with a range of values reported, from 0.001% injected dose (ID)/gram tissue (Armitage et al 1984;Halpern et al 1985;Halpern and Dillman 1987;Carrasquillo et al 1988) to 0.007%ID/g (Armitage et al 1985;Davidson et al 1989). The lowest value, 0.001%ID/g, was adopted as a worst-case study, with normal tissue activity concentration set at a level of 0.0005%ID/g to be consistent with this at the lowest turnout to normal tissue ratio of 2:1.…”