Anti-tumor activity of radiopharmaceutical medication based on biospecific antibodies to tumor-associated stroma elements and 177lutecium

Abstract

Radiopharmaceutical targeted medication based on biospecific antibodies to tumor-associated stroma elements and 177lutecium (177Lu-DOTA-anti-CTLA4-GITR) potential anti-tumor activity was studied in two courses: one-time administration and two injections with a considerable lag. Subcutaneously transplanted experimental colonic carcinoma (AKATOL; cell line CT26 EGFP) with high expression of green fluorescent protein (eGFP) and additional expression of target tumor-associated stroma molecules CTLA4 and GITR was used as a model in BALB/c male mice. The experimental radiopharmaceutical targeted medication proved to possess high pharmacologic activity against the tumor under study. It was apparent in valid increase of experimental animals mean lifespan, tumor debut latent period inhibition and clinically valid tumor growth rate slowdown. Double administration of 177Lu-DOTA-anti-CTLA4-GITR proved to be more effective than one-time one, however neither of them managed to yield statistically valid difference in safety levels.