In vivo antitumor activity demonstrated with squamous carcinoma reactive monoclonal antibody-Vinca immunoconjugates.

An immunoconjugate (PF1/D-DAVLBHYD), made with the squamous carcinoma reactive monoclonal antibody PF1/D and a derivative of vinblastine, DAVLBHYD, was shown to suppress established T222 human tumor nude mouse xenografts using a multidose protocol. Treatments of xenograft-bearing mice with free drug, free antibody, or a mixture of the two, were unsuccessful at achieving suppression without associated toxicity, using otherwise identical protocols. A Vinca conjugate with a related squamous carcinoma reactive monoclonal antibody, PF1/B, was shown to have similar tumor suppressive activity. In a dual immunoconjugate therapy protocol, PF1/D-DAVLBHYD and PF1/B-DAVLBHYD had additive antitumor effects which were consistent with their complementary tumor reactivity.