Corynebacterium parvum and cyclophosphamide as combination treatment for a murine mammary adenocarcinoma.

Weekly i.p. injections of killed Corynebacterium parvum and of cyclophosphamide (given on different days) strongly inhibited growth of a transplantable murine mammary adenocarcinoma. A significant portion (40 to 80%) of animals could be made tumor free by means of combined therapy. No tumor-free survivors were obtained with C. parvum alone, and tumor-free mice were obtained with cyclophosphamide alone only at the expense of a high incidence of deaths due to drug toxicity. No evidence of tumor rejection immunity was detected in the tumor-free survivors from the combined treatment protocols, suggesting that this therapeutic regimen is not associated with tumor rejection immunity.