Antitumor effect of levamisole in combination with anaerobic corynebacterium,OK-432 (streptococcal preparation), and chemotherapy in mice

Summary The antitumor activity of levamisole (LMS) used in combination with anaerobic Corynebacterium liquefaciens (CL), OK-432 (OK), or anticancer chemotherapy was investigated in ascitic tumor-bearing mice. With the combination of CL and LMS or OK and LMS, the best result was observed when LMS was given after CL or OK. In the combination of CL and LMS with mitomycin-C (MMC) or 5-fluorouracil (5-FU), a significant increase in mean survival time and number of 50-day survivors was seen when LMS was given after CL. Finally, with combinations of MMC and two of these three immunostimulants, the best inhibitory effect on tumor growth was observed with the combination of CL and LMS or that of CL and OK. It was also clearly demonstrated that LMS should be administered after CL, and CL after OK. The reverse order of administration significantly depressed the antitumor activity.