EFFECT OF CORYNEBACTERIUM-PARVUM IN COMBINATION WITH 5-FLUOROURACIL, L-PHENYLALANINE MUSTARD, OR METHOTREXATE ON INHIBITION OF TUMOR-GROWTH

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (8) , 2714-2719
Abstract
Previous reports demonstrated conclusively that cyclophosphamide administered asynchronously with C. parvum (CP) results in greater C3H [mouse] mammary tumor inhibition than that observed with either agent alone. An analysis of this combination revealed that the chemotherapeutic component contributes more significantly to tumor inhibition than the immunotherapeutic one. This study was conducted to investigate the inhibition of C3H mammary tumors by other chemotherapeutic agents when used with CP. The results demonstrated that 60 mg of cyclophosphamide/kg, 90 mg of 5-fluorouracil/kg and 10 mg of L-phenylalanine mustard/kg administered weekly have similar tumor-inhibiting properties. The addition of CP enhanced the tumor-inhibiting properties of each agent but to differing degrees. The effect of the immunopotentiator when usedin combination with alkylating agents was greater than that seen when it was used with the antimetabolite 5-fluorouracil. The tumor inhibition observed when cyclophosphamide was administered asynchronously with CP was signficantly greater than that observed when L-phenylalanine mustard was similarly used. Of particular interest was the finding that the addition of CP to a combination of chemotherapeutic agents resulted in no greater tumor growth inhibition than that which occurred when CP was used along with the most effective single agent in the combination. The data indicated that, contrary to clinical impression, there is no evidence that CP through its toxicity-sparing effect permits the utilization of larger doses of chemotherapy. Consideration was given to the mechanisms that might account for the differences in tumor growth inhibition encountered when CP was used with different chemotherapeutic agents.