Increased therapeutic effect of vinca alkaloids targeted to tumour by a hybrid-hybrid monoclonal antibody.

Unmodified vinblastine (VLB) targeted through one of the antigen combining sites of the hybrid-hybrid 28.19.8 monoclonal is potentially more effective in suppressing the growth of established MAWI tumour xenografts implanted on nude mice than free VLB in the absence of the targeting agent, presumably due to an increased local drug concentration. Our efficacy results in this study suggest that drug, specifically removed from the circulation by hybrid-hybrid antibody previously located to the tumour mass, can be made available in a pharmacologically active from. Histological analysis of the treated tumours revealed dramatic changes in the tumour organisation with only a few surviving tumour cells with altered morphology.