The Evolution of the Treatment of Chronic Myelogenous Leukemia

Chronic myelogenous leukemia(CML)is a myeloproliferative neoplasm caused by a reciprocal translocation (t 9 ; 22) (q34 ; q11). The finding that the constitutive tyrosine kinase activity of the BCR-ABL1 fusion protein, which is produced by fusing the ABL1 and BCR genes, is involved in the pathogenesis of CML has led to the development of drugs targeting the BCR-ABL1 fusion protein. Imatinib, a first-generation tyrosine kinase inhibitor(TKI), was introduced in 2001 as a treatment for CML, dramatically changing CML therapy. With the advent of imatinib, disease progression is largely prevented and the prognosis of CML patients is markedly improved, allowing a substantial proportion of patients to remain in the chronic phase for an extended period of time. In the TKI-era, it is no longer the primary disease that defines the long-term prognosis of CML patients, but rather comorbidities other than CML and adverse events(AEs), including cardiovascular events, and management to avoid AEs associated with long-term TKI use has become increasingly important. In recent years, treatment-free remission(TFR)is becoming a new therapeutic goal, as many reports have shown that some patients who have achieved deep molecular response with TKIs can maintain long-term TFR without relapsing after TKI discontinuation.