Therapy of chronic myelogenous leukaemia with interferons

Therapy of Philadelphia positive chronic myelogenous leukaemia (CML Ph1) with alpha interferon (IFN-alpha) resulted in a high frequency of haematological remissions. Effective suppression of the malignant Ph1 clone and concomitant partial or complete restoration of normal haemopoiesis is reproducibly noted in a proportion (30%-50%) of the patients. This and the low incidence of blast crisis underscore the profound effect this therapy has on the disease. Marked heterogeneity in the response to IFN-alpha was noted as well, and sensitivity or resistance to interferon was phenotypically indistinguishable. Studies of the IFN-resistant disease failed to disclose alteration in IFN receptors or in IFN-inducible genes and are suggestive, therefore, of a limited alteration in IFN-induced intracellular pathways.