Comparative antitumor effects of Corynebacterium parvum, Bordetella pertussis, Bacillus Calmette-Guérin, and levamisole alone or in combination with cyclophosphamide in the CaD2 murine mammary adenocarcinoma system.

The antitumor efficacy of various immune stimulants [Corynebacterium parvum, Bordetella pertussis, and Bacillus Calmette-Guérin (BCG)] and levamisole alone or in conjunction with cyclophosphamide (CY) was studied in the CaD2 mammary adenocarcinoma system using schedules developed previously with C. parvum and CY. Weekly systemic treatment with C. parvum, B. pertussis, or BCG was effective in controlling tumor growth and had equivalent antitumor effects, but weekly treatment (or a single treatment) with levamisole was ineffective. Weekly treatment with B. pertussis was better than treatment given only once, but repeated treatment with C. parvum or BCG was not more effective than a single treatment with these agents. When administered as a single systemic injection, C. parvum was superior to B. pertussis in controlling tumor growth, but a single systemic injection of BCG was as effective as C. parvum. Systemic administration of immune stimulants had variable effects on survival, which were sometimes not correlated with effects on tumor size. Combined treatment with BCG and CY was significantly more effective than CY treatment alone in controlling tumor growth in most trials, as was combination treatment with C. parvum and CY. Combination treatment with B. pertussis and CY was not better in prolonging survival than CY alone. Levamisole rarely improved the antitumor effect of CY chemotherapy and had no effect on survival compared to the effect of CY alone.