Alpha interferon: perspectives in the biotherapy of chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a clonal disorder characterized by a cytogenetic translocation, the Philadelphia chromosome (Ph). CML terminates in blastic transformation with additional secondary cytogenetic events. Standard chemotherapy rarely results in Ph suppression and is associated with three- to four-year overall survival. Alpha interferon has a mechanism of action distinct from that of chemotherapy. Although the percentage of patients that can be expected to achieve complete hematologic remission (CHR) with alpha interferon is similar to the percentage expected with chemotherapy, nearly 40% of patients undergoing treatment with alpha interferon have some degree of Ph suppression. Present studies will determine whether interferon delays blastic transformation and improves survival in CML. This paper addresses current issues in the alpha interferon therapy of this malignancy, such as optimum dose, duration of therapy, antibody formation, toxicities, and altered characteristics of blastic transformation. Alpha interferon will have a major role, both therapeutic and prognostic, in the management of CML.