Response to the combined administration of interferons alpha and gamma after failure of single interferon therapy in chronic myelogenous leukaemia.

A previously untreated patient with benign phase chronic myelogenous leukaemia (CML) was treated with recombinant Interferon alpha-2 b. Haematological remission was induced for a total of twelve months. Thereafter, the patient developed resistance to Interferon alpha manifested by an increase in leucocyte counts despite dose escalation (up to 7 x 10(6) IU/day s.c.). Subsequent treatment with recombinant Interferon gamma failed to control myeloid proliferation. However, combined administration of both Interferon alpha and Interferon gamma resulted in a renewed haematological remission which lasted six months.