Targeted treatment of chronic myeloid leukemia: role of imatinib

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by clonal expansion of pleuripotent hematopoetic stem cells. The incidence of CML is 1 to 2 cases per 100,000 people per year; in the Western Hemisphere, CML accounts for 15% of leukemias in adults. Discovery of the specific karyotypic abnormality of the Philadelphia (Ph) chromosome in the pathogenesis of CML has led to a better understanding of the disease and hence to an advancement of targeted therapeutics. Availability of imatinib as an accepted targeted therapy in newly diagnosed patients has changed the treatment paradigm in CML. The majority of CML patients in chronic phase achieve excellent and durable responses with standard-dose imatinib. Mechanisms of primary and secondary resistance to imatinib in CML have been extensively studied and newer tyrosine kinase inhibitors are now being evaluated for clinical use. It is important that at any time the CML treatment and response remain optimal and thus patients on imatinib require continuous monitoring for early detection of resistance. This review will discuss the treatment and guidelines for monitoring CML patients in the imatinib era.