BACKGROUND/AIM: Imatinib mesylate, a selective Bcr-Abl tyrosine kinase 
inhibitor, has revolutionized the treatment of Bcr-Abl positive chronic myeloid 
leukemia and become the standard of care for this disease. The aim of this study 
was evaluation and analysis of cytogenetic response in different intervals and 
risk groups as well as finding association between pre-treatment characteristics 
and later probability of achievement of major cytogenetic response.
METHODS: We analyzed a total of 22 adult patients with newly diagnosed 
Philadelphia positive early chronic phase chronic myeloid leukemia treated at 
our institution from June 2006 to December 2009.
RESULTS: The median follow-up time for patients during treatment with imatinib 
was 25.7 months (range, 12-42 months). A complete hematologic response was 
achieved in all of the analyzed patients within 6 months from the start of the 
treatment. The major cytogenetic response rate was 81.8%, and the complete 
cytogenetic response rate was 72.7%. The patients with low or moderate relative 
risk had the rate of complementary achieving major and complete cytogenetic 
response of 75-90%. A multivariate analysis identified the following independent 
prognostic factors for achieving major cytogenetic response: the absence of 
splenomegaly, white blood cell count less than 10 x 10(9)/L, the platelet count 
less than 450 x 10(9)/L, the presence of less than 5% of bone marrow blasts and 
basophils, the absence of blasts in peripheral blood, the presence of less than 
7% of basophils in peripheral blood.
CONCLUSION: Patients who early achieve complete and major cytogenetic response 
as well as those with low and moderate relative risk have a higher rate of 
achieving and maintaining complete cytogenetic response. There are also 
characteristics of patients before treatment that may indicate the treatment 
outcome.