OBJECTIVETo understand the prognostic value of early monitoring BCR-ABL transcripts in patients with chronic myeloid leukemia (CML) after treatment with imatinib, and to provide the information for early assessment of prognosis and treatment options.

METHODSThe clinical data of 251 patients with CML in chronic phase (CML-CP) who received imatinib as first-line therapy were retrospectively analyzed, the progression-free survival (PFS)and overall survival (OS) between different BCR-ABL transcriptional level at 3 and 6 month after imatinib treatment were compared. Meanwhile, Chi-square test and logistic regression were used to analyze the risk factors for disease progression.

RESULTSAt 3 months after imatinib treatment BCR-ABL transcriptional levels>10%, >1%-≤ 10% and ≤ 1% were found in 92, 94 and 64 patients, their PFS were 53.3%, 71.3% and 86.2%, respectively. The results showed that the PFS of patients with low BCR-ABL transcriptional levels was significantly superior to that with high BCR-ABL transcriptional levels for CML at 3 months treatment (P<0.05). The OS of three group did not reach statistical significance (92.4% vs 96.8% vs 93.8%, P> 0.05). When 182 patients received imatinib treatment at 6 months, 22 patients with BCR-ABL transcriptional levels>10%, 50>1% -≤ 10% and 110 ≤ 1%, their PFS were 27.3% vs 66.0% vs 82.7% (P<0.05), the OS of three groups were 86.4% vs 94.0% vs 100%. There were significant differences among the three groups (P<0.05). Logistic regression confirmed that the level of BCR-ABL transcriptional level at 3 and 6 months after imatinib treatment was independent factor to influence the progress of disease.

CONCLUSIONIt is important for the prognosis evaluation of CML patients to monitor BCR-ABL transcriptional level at 3 and 6 months after imatinib treatment.