Immunological evaluation of a streptococcal preparation (OK-432) in treatment of bladder carcinoma.

When 21 patients with bladder cancer (transitional cell carcinoma) were given local and systemic injections of a streptococcal preparation, OK-432, tumor regression was observed in 3 cases (14.3%). The marked infiltration of lymphocytes observed on histological examination of regressed tumors suggested that a host-mediated action was involved in the antitumor effect of OK-432.