We previously found that the ability to generate cytotoxic cells induced by in vitro activation of peripheral blood mononuclear cells (PBM) with OK-432, a bacterial immunopotentiator, was markedly increased following intravenous administration of a single dose of mitomycin C (MMC) in cancer patients. On the basis of this clinical finding, we designed a treatment regimen that consisted of MMC 12 mg/m2 intravenously on day 1 and OK-432 5 Klinische Einheit (KE) intradermally on days 6, 8, and 11, when the generation of OK-432 activated killer cells had been shown to be significantly augmented. Then, it was followed by long-term tegafur. Fifteen patients with stage III gastric carcinoma who had undergone curative resection were treated with the above regimen. The survival of these patients was significantly better than that of 26 comparable stage III patients concurrently treated with MMC 12 mg/m2 alone, followed by long-term tegafur (P < 0.01). The results indicate that OK-432 combined with MMC may be effective against stage III gastric carcinoma, when these agents are used probably in an appropriate combination.
