INTRODUCTION: Imatinib mesylate, a selective Bcr-Abl tyrosine kinase inhibitor, 
has proved to be most effective therapy of Philadelphia chromosome-positive 
chronic myelogenous leukemia. Imatinib induces complete haematological and 
cytogenetic response in high percentage of patients.
OBJECTIVE: The aim of this study was to identify potential prognostic factors 
before beginning treatment with imatinib associated with complete cytogenetic 
response.
METHODS: We analyzed 20 patients with newly diagnosed Philadelphia positive 
chronic myelogenous leukemia treated at our institution from June 2006 until May 
2009. These patients were treated with imatinib mesylate in oral dose of 400 to 
800 mg daily. Complete blood counts were performed every month, while serum 
chemistry evaluations and bone marrow evaluations including morphology and 
cytogenetics were performed every 6 months.
RESULTS: Of the 20 patients analyzed in this study, 19 (95%) achieved complete 
haematologic response within three months. In all patients cytogenetic analyses 
were done and all have achieved absolute cytogenetic response. The best 
cytogenetic response rate at any time during study treatment among 20 patients 
was: complete cytogenetic response in 15, partial cytogenetic response in three 
and minor cytogenetic response in two patients. Among 11 observed base-line 
patients' characteristics five were independent predictors of a high rate of 
complete cytogenetic response; the absence of blasts and basophils in peripheral 
blood, the presence of less than 5 percent of bone marrow blasts, white blood 
cell count less than 10 x 10(9)/L and the absence of splenomegaly (p < 0.01).
CONCLUSION: Our results showed that some pre-treatment characteristics of 
patients might be the cause of differences in treatment outcome. On the basis of 
this analysis, we identified several pre-treatment patients' characteristics to 
be independent prognostic factors for achievement of complete cytogenetic 
response.