OBJECTIVETo evaluate the therapeutic effect of imatinib on chronic myeloid leukemia (CML) in different phases and analyze the factors that may affect the effects.

METHODSEighty-five patients with CML in chronic phase, 24 in accelerated phase and 19 in blastic phase patients were treated with imitinib. The hematologic response, cytogenetic response, molecular response, overall survival (OS), progression-free survival (PFS) and adverse events were analyzed in these groups.

RESULTSThe rates of complete hematologic response (CHR), complete cytogenetic response (CCyR) and complete molecular response (CMoR) of the patients in chronic phase were 100%, 82.4% and 21.2%, respectively, and the 5-year OS and PFS of these patients were 92.1% and 84.7%. All these rates were significantly higher than those in patients in accelerated and blastic phases (P<0.0001). The CCyR, CMoR, 5-year OS and PFS in the 42 newly diagnosed patients in chronic phase were 92.9%, 26.3%, 100% and 95.2%, respectively, all significantly higher than those in patients with interferon therapy failure (P<0.001). Severe leukocytopenia and thrombocytopenia occurred at greater frequencey in AP and BP patients than in chronic phase patients (P<0.0001). Non-hematologic toxicity was rarer and milder in patients in chronic phase. Multivariate analysis showed that interferon therapy prior to imitinib treatment and prolonged drug cessation were the independent factors that affected the achievement of cytogenetic response and PFS.

CONCLUSIONEarly imitinib therapy can be effective and safe, and should be used as the first line drug for CML.