GROWTH-INHIBITION OF XENOTRANSPLANTED HUMAN CARCINOMAS BY A MONOCLONAL-ANTIBODY DIRECTED AGAINST THE EPIDERMAL GROWTH-FACTOR RECEPTOR

In the athymic nude mice model with xenotransplanted human carcinomas, the effect of a monoclonal antibody (MAb 425), directed against the h uman epidermal growth factor (EGFR), on tumour growth was studied. Fiv e different solid human breast carcinomas and one vulvar epidermoid ca ncer cell line (A431) were transplanted in nude mice, and treated with MAb 425 2.2 mg intraperitoneally (i.p.) on day 7 post-transplantation . Tumours with EGFR concentrations of greater than or equal to 16 fmol /mg soluble cytosolic protein showed growth inhibition, whereas the gr owth pattern of EGFR-negative tumours was unaffected. Variation of MAb 425 dosage (1.1 versus 2.2 mg) revealed no difference in the growth i nhibiting effect. Different application schedules (application on day 0, 12 or 26) showed different onsets and durations of tumour growth in hibition. Repeated application (1.1 mg, day 0 and 12) was followed by a prolonged inhibitory effect, Our results suggest that growth inhibit ion of EGFR-positive tumours by MAb 425 may lead to an additional trea tment option for patients with EGFR-positive cancer.