Interferon in the treatment of myeloproliferative diseases.

Interferon alfa has been used in the treatment of myeloproliferative disorders, particularly chronic myeloid leukemia, polycythemia vera, and idiopathic thrombocythemia. The effectiveness of interferon alfa in agnogenic myeloid metaplasia needs additional evaluation, although preliminary evidence suggests that it may be more efficacious when used in the cellular (ie, proliferative) phase than when the marrow is fibrotic or osteosclerotic. Cytogenetic and molecular changes after interferon alfa therapy are apparent in patients with chronic myeloid leukemia, as manifested by change in the Philadelphia chromosome and BCR-ABL gene, respectively. The exact role of interferon in prolonging the life of chronic myeloid leukemia patients, however, remains to be determined in larger studies of longer duration. Interferon treatment seems to be well tolerated, and the frequency of treatment-limiting toxicity is low. Data to date suggest that interferon alfa may be a new and effective drug for the treatment of the myeloproliferative disorders.