Evaluation of imatinib failure in patients with chronic myeloid leukemia

Abstract EN

Objective : To evaluate imatinib mesylate failure in patient with chronic myeloid leukemia.

Methods : The study was conducted on eighty patients with Philadelphia positive (ph+) chronic myeloid leukemia-chronic phase who were treated in the hematology unit and outpatient clinic in Ibn-Sina Teaching Hospital in Mosul city from May 2007 to May 2014, of them forty four males and thirty six females.

Demographic data were obtained from the patients file, including serial complete blood count, peripheral blood smear examination, flourescent in situ hybridization, and bone marrow examination, at baseline, 3, 6, 12 and 18 months of treatment.

The threshold defining failure, suboptimal and optimal response according to the standard criteria.

The Sokal score is based on age, spleen size, and peripheral blood platelet count and blast count.

Patients are classified as being low-risk (Sokal score <0.8), intermediate-risk (0.8 to 1.2), or high-risk (>1.2).

Sokal prognostic scoring was performed on all the cases, using standard formula.

Accelerated-phase CML was defined by the presence of 15 to 19 percent blasts in blood or marrow, the presence of at least 30 per-cent blasts plus promyelocytes in blood or marrow, or the presence of at least 20 percent basophils in blood.

Blast-phase CML was defined by the presence of at least 20 percent blasts in blood or marrow or the presence of extramedullary blastic disease.

Results: Fifty eight patients (72.5%) showed an optimal response, while the remaining 22 (27.5%) found to have failure ranging from primary failure (5 patients), secondary failure (12 patients), intolerance of imatinib, and death (5 patients).

Splenomegaly, leukocytosis, thrombocytosis, basophilia, any peripheral blasts or marrow blasts >5%, and clonal evolution were all inversely related to major cytogenetic response.

Patients who started therapy within 12 months of diagnosis had significantly higher response rates.

Conclusions : Majority of the (58 patients, 72.5%) had an optimal response, 5 of the 22 patients with failure had primary failure, while the remaining 17 patients had either secondary failure (12), drug intolerance or death due to sepsis.

Prolonged duration between diagnosis and start of imatinib was an independent predictor of failure.