Combination therapy of ACNU and ifosfamide in tumor bearing mice with M2661 breast cancer, B16 malignant melanoma or C38 colon cancer

Three murine tumor lines, B16 melanoma, C38 colon cancer and M2661 breast cancer, were used to evaluate the therapeutic efficacy of the drug combination ACNU and ifosfamide. For each tumor type five treatment groups of 12 mice each were studied, which respectively received 16.5 mg/kg ACNU, 150 mg/kg ifosfamide, 33 mg/kg ACNU, 300 mg/kg ifosfamide or 16.5 mg/kg ACNU + 150 mg/kg ifosfamide. One group served as controls. Growth delay was measured as the endpoint. In the B16 and C38 tumor lines both drugs were active and showed additive antitumor effects. However, no synergism was observed. Neither ACNU or ifosfamide or the combination of both had any activity against the M2661 tumor line.