Chronic myelogenous leukaemia (CML): an update

The management of chronic myelogenous leukaemia (CML) has undergone a major change over the past 5 years. All newly diagnosed patients of CML are candidates for imatinib mesylate therapy. Almost 95% of patients with early chronic phase CML achieve complete haematological remission (CHR) and nearly 80% achieve complete cytogenetic response (CGR; 0% Philadelphia [Ph] chromosome-positive metaphases). These responses are stable in most patients with a risk of relapse of 4%-6% per year. For patients with advanced CML (accelerated phase and blast crisis), achievement of CHR and major (complete and partial) CGR occurs in 25%-37% and 10%-30% of patients, respectively. Most investigators agree that patients who fail to achieve CHR by 12 weeks, have partial cytogenetic response (< 35% Ph-positive metaphases) at 12 months, have CGR by 18 months, who relapse after initial response to imatinib, and those with a high Sokal score or in an advanced phase of CML should be considered for allogeneic stem cell transplantation (SCT). Despite Ph negativity with imatinib treatment, most patients continue to remain BCR-ABL positive on molecular studies, and require treatment indefinitely. Identification of patients at high risk for relapse and understanding the mechanisms to unravel resistance to imatinib are current areas of active research.