OBJECTIVETo evaluate the efficacy of imatinib mesylate (IM) for patients with newly diagnosed chronic myeloid leukemia (CML) and patients after failure of Recombinant Human interferon-α2b (IFN-α2b) therapy.

METHODSA total of 86 patients with CML in chronic-phase, including 61 newly diagnosed cases and 25 cases of IFN-α2b failure, who received IM at 400 mg daily were retrospectively analyzed. Conventional cytogenetic analysis of R-banding was used to detect chromosome abnormalities and real-time PCR was used to detect BCR-ABL fusion gene.

RESULTS81.9% of newly diagnosed patients and 36.0% of IFN-α2b failure patients achieved partial cytogenetic response (PCyR) by 6 months. In addition, 86.9% of newly diagnosed patients and 68.0% of IFN-α2b failure patients achieved complete cytogenetic response (CCyR) in 24 months. There was significant difference between two groups (P<0.001). The median time achieved CCyR in newly diagnosed group and IFN-α2b failure group were 6 months and 15 months, respectively. Compared with newly diagnosed group, IFN-α2b failure group showed lower rate of complete molecular remission (CMR) (70.4% vs 40.0%, P=0.033). There are 14 patients (22.9%) in newly diagnosed patients with cytogenetic resistance, among whom 4 with primary cytogenetic resistance; while there were 14 patients (56.0%) in IFN-α2b failure group with cytogenetic resistance, all of whom with primary resistance.

CONCLUSIONCompared with newly diagnosed patients, CML patients after failure of IFN-α2b therapy have a high rate of primary cytogenetic resistance and low response rate to IM.