Early molecular response in chronic myeloid leukemia patients predicts future response status.

Imatinib is the frontline therapy for chronic myeloid leukemia (CML) management. Most of the CML patients achieve major responses, but a proportion (nearly 25-35%) of them develop drug resistance. Molecular monitoring using quantitative real-time PCR at regular intervals according to European LeukemiaNet (ELN) helps in the assessment of long-term outcomes in imatinib-treated CML patients. Eighty-four CML patient samples (42 at diagnosis and 42 at 3-month intervals from the same patients) were analyzed for Bcr-Abl transcript levels. Quantification results revealed that the patients with <10% Bcr-Abl levels at 3 months had higher rates of complete cytogenetic response (CCyR) and optimal responses compared to patients with >10% Bcr-Abl levels (P < 0.0001). Patients with >10% Bcr-Abl levels were found to have 25.0% of suboptimal response and 3.57% of failure to imatinib at standard dose. Hence, the present study confirms that early molecular monitoring at 3 months after imatinib initiation helps in predicting the concurrent cytogenetic response and treatment optimization in CML patients.