Imatinib Therapy in Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) is a clonal proliferative disease originating from a pluripotential stem cell in which a 9:22 translocation, Philadelphia (Ph) chromosome, results in the production of BCR-ABL fusion protein that has constitutive tyrosine kinase activity and deregulates signal transduction pathways, thus causing leukemia. The natural course of CML is usually triphasic (chronic, accelerated and blast-crisis phases). The blast-crisis phase is refractory to standard chemotherapy. The introduction of imatinib, a selective inhibitor of the BCR-ABL tyrosine kinase, has caused rapid change in the treatment protocols for patients with CML. The great efficacy of imatinib in achieving a cytogenetic response has been demonstrated in many trials, but long-term clinical data regarding imatinib are not yet available.