Success and Challenges in the Management of Chronic Myeloid Leukemia

Abstract

Chronic myeloid leukemia (CML) is one of the most common myeloproliferative neoplasms characterized by the presence of Philadelphia chromosome, that is, t(9:22), a reciprocal translocation between long arms of chromosomes 9 and 22. In its natural course CML has three phases, that is, chronic phase, accelerated phase, and blast crises phase. Peripheral blood shows marked leukocytosis and left shift. Diagnosis is confirmed by demonstration of specific molecular abnormality by polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH) method or cytogenetics. The drug of choice is tyrosine kinase inhibitor (TKI); imatinib. Other TKIs are dasatinib and nilotinib. Most patients respond and have almost normal life span. However, challenges remain. At present the drug is prescribed for lifelong. Recent studies have shown that the drug may be stopped in certain groups of which around 50% remain in long term remission (operational cure). However, around 20% did not respond and showed resistance. Research is in progress to find out the mechanism of resistance and newer therapeutic modalities or agents.