BCR-ABL Transcript Level and Neutrophil Alkaline Phosphatase Activity in CML Patients Treated with Imatinib

Abstract

The efficacy of imatinib mesylate has been demonstrated in patients with chronic phase of chronic myeloid leukemia (CML) as well as in advanced phase disease. The aim of this study was to evaluate the molecular response to 12 months of imatinib treatment as assessed by logarithmic reduction in BCR-ABL transcription levels, in Turkish chronic phase CML patients. Seventy-seven chronic phase CML patients were included in this multicenter, retrospective study. All patients received 12 months of oral 400 mg/day imatinib treatment. Hematological, major molecular and complete molecular response rates were evaluated after 12 months of treatment. In addition, neutrophil alkaline phosphatase (NAP) activities before and after treatment of 15 patients were also analyzed. At 12 months of treatment, hematological, major molecular and complete molecular response rates were 87%, 58.5% and 32.5%, respectively. Major molecular response rates did not significantly differ among Sokal risk groups. In addition, a significant increase in NAP levels were seen after treatment compared to baseline (p = 0.001). Although there was a negative correlation between NAP activity and BCR-ABL transcript level, this was not statistically significant (r= -0.340, p=0.06). Twelve months of imatinib treatment resulted in a molecular response in substantial proportion of CML patients without any difference among risk groups. In addition, NAP score may serve as a tool for the clinical follow-up of the response to imatinib treatment in CML patients.