Chronic myeloid leukemia: Current first-line treatment options

Historically, CML was treated with busulfan or hydroxyurea, and was associated with a poor prognosis. 2,3 These agents controlled the hematological manifestations of the disease, but did not delay disease progression. Treatment with interferon alfa (IFNα) produced complete cytogenetic responses in 5 - 25 % of patients with CML in chronic phase (CP), and improved survival compared with previous treatments. 4 Combining IFNαwith cytarabine produced additional benefits. 5,6 Allogeneic stem cell transplantation (alloSCT) may be curative in CML, but it is applicable to only a fraction of CML patients and carries a significant risk of morbidity and mortality. In one recent study, the 5-year survival with IFNα(in most instances followed by imatinib) was significantly superior to that with alloSCT. 7 Imatinib mesylate, a potent and selective BCR-ABL tyrosine kinase inhibitor, is now established first-line standard therapy in CML. A complete cytogenetic response can be achieved in 50 - 60 % of patients treated in chronic phase after failure with IFNα8,9 and in over 80 % of those receiving imatinib as firstline therapy. 10,11 Responses are durable in most patients treated in early chronic phase, particularly among those who achieve major molecular responses (e.g. ≥ 3-log reduction in transcript levels). 12,13 Here we review the most current information regarding first-line therapy in CML, and briefly summarize the status of previous drugs such as IFNαand cytotoxic agents.