How to choose frontline therapy for chronic myelogenous leukemia: so many drugs, not so many patients

With the development of tyrosine kinase inhibitors (TKIs), the management and outlook for patients with chronic myelogenous leukemia (CML) have completely changed over the past 10 years. Imatinib was the first TKI approved to treat CML in the chronic phase. After their initial approval as second-line agents, dasatinib and nilotinib were compared with imatinib in the first-line setting in 2 randomized trials. Both trials showed that therapeutic milestones (complete cytogenetic remission and major molecular remission) occurred earlier with these newer agents, leading to their approval for the treatment of newly diagnosed CML. Therefore, 3 different TKIs are now available for treating CML. Long-term follow-up of patients treated with imatinib shows that the attainment of therapeutic milestones by 12 months of therapy leads to better long-term outcomes. Most patients who experience disease progression on imatinib do so within the first 3 years of therapy. Therefore, one can argue that dasatinib or nilotinib should be chosen to treat patients with newly diagnosed CML. However, these agents do not have the long-term track record of imatinib. This article summarizes the published data and reviews the rationale in choosing the appropriate TKI for first-line treatment of CML in the chronic phase.