INTRAVESICAL ADMINISTRATION OF INDIUM-111-LABELED HMFG2 MONOCLONAL-ANTIBODY IN SUPERFICIAL BLADDER CARCINOMAS

Tumour-associated HMFG2 monoclonal antibody (MAb) was labelled with in dium-111 and administered intravesically to 20 patients with known or suspected superficial bladder carcinoma. The antibody solution was kep t in the bladder for 1 hr and was then washed out. Cystoscopy was perf ormed at 2 and 24 hr after instillation. Radioactivity of tumour and n ormal tissue obtained from the bladder during cystoscopy and cells rec overed from urine after the instillation were counted in a gamma-count er. Conventional histology, immunocytochemistry and autoradiography we re also performed. Mean uptake at 2 and at 24 hr was higher in tumours than in normal samples. Autoradiography showed selective accumulation of radioactivity in cells which expressed the antigen detected by the HMFG2 MAb. There was no correlation of tumour uptake with the grade o f tumour. No radioactivity was found in the blood of patients after th e instillation. Based on dosimetric calculations, however, the radiati on dose that can be delivered to the tumours is not sufficient to be c ytotoxic, possibly due to inadequate penetration and retention by tumo ur tissue. Nevertheless, the significant difference between antibody u ptake by the tumours and that by normal urothelium, observed in our st udy, allow for the possibility of using this approach therapeutically. (C) 1993 Wiley-Liss, Inc.