Identifying the time to change BCR-ABL inhibitor therapy in patients with chronic myeloid leukemia.

Many patients newly diagnosed with chronic myeloid leukemia in the chronic phase (CML-CP) respond to imatinib. Those experiencing imatinib resistance/intolerance require alternative treatments. Delayed responses increase the risk of transformation to advanced disease, mutation development and loss of response. In retrospective analyses, achieving faster, deeper responses correlated with improved long-term response and outcome. Changing therapy to obtain early responses may improve the depth and speed of response, ultimately improving the outcome. Although trials are ongoing, there are no prospective data indicating that changing from imatinib to later-generation inhibitors reverses the inferior prognosis and improves the outcome. We describe the rationale behind early therapy change in CML-CP.