OBJECTIVETo compare the efficacy and drug resistance of imatinib in patients with chronic myeloid leukemia (CML) at chronic phase (CP) and advanced phase (accelerated phase and blast crisis (AP+BC).

METHODSForty-two patients with CML were treated with imatinib of different doses(CP 400 mg/d, AP+BC 600 mg/d), and the efficacy and drug resistance of the 2 groups were compared. The median follow-up time was 24 months (3-42 months).

RESULTSThe complete hematological remission rate (CHR), the major cytogenetic remission rate (MCyR) and complete molecular remission rate (CMoR) in the CP group were 100%, 89.6% and 20.1% respectively, while those in advanced phase group were 46.2%, 308% and 0; survival rate of 42 months in CP patients was 76.7%, and that in advanced phase group was 39.2%, the difference between them was statistically significant (P<0.05). The incidence of severe hematologic adverse reaction in advanced phase group was higher than that in CP Group; among 42 cases of CML, the drug-resistance happened in 13 cases, out of them 9 cases was CML in advanced phase; the drug resistance rate in CML in advanced phase group (69.2%) was significantly higher than that in CML-CP group(13.8%). The correlation factor analysis showed that the effects of the advanced phase and the lower dose of the drug were statistically significant.

CONCLUSIONImatinib can provide certain curative effect for CML patients at different phases, especially for the patients at chronic phase; the early MCyR for patients with CML is an important factor in long-term survival; drug resistance is an important factor affecting the efficacy of imatinib; The incidence of imatinib drug resistance at the late stage has been found to be higher.