Combined interferon‐antimetabolite therapy of murine L1210 leukemia

Abstract

To assess the interaction of interferon with established chemotherapeutic agents, L1210 murine leukemia in BDF/1 mice was treated with methotrexate, 6‐mercaptopurine, Adriamycin, cytosine arabinoside or cyclophosphamide alone or in combination with mouse L‐cell (Newcastle disease virus‐induced) interferon or with interferon‐free tissue culture medium. Also studied was the effect of interferon on the combined 6‐mercaptopurine‐methotrexate therapy of this tumor. Interferon failed to enhance the response of L1210 leukemia to 6‐mercaptopurine, adriamycin, cytosine arabinoside or cyclophosphamide. The addition of interferon to all methotrexate‐containing regimens increased mean survival time (P < 0.05). The increase in survival of host animals treated with 6‐mercaptopurine‐methotrexate and interferon was sustained through four transfer generations despite evolving resistance to this antimetabolite combination. Copyright © 1981 American Cancer Society