Ctopenia Following Imatinib Treatment of Chronic Myeloid Leukemia (Cml) in Kenya: a Study at Gipap Clinic, Nairobi Hospital

Abstract

Background: Imatinib mesylate is the preferred initial treatment for all phases of Philadelphia positive CML. During treatment, patients may develop cytopenia, namely anemia, neutropenia or thrombocytopenia either as monocytopenia, bicytopenia or pancytopenia. The cytopenia is often due to toxicity but may also arise from disease transformation or resistance to therapy. Objective: The study aimed to determine the type, grade, time to development, and duration of the cytopenia. In addition, the risk factors associated with cytopenia including sociodemographic characteristics, clinical characteristics and baseline laboratory characteristics were studied. Methods: This was a retrospective case-control study at the GIPAP clinic at the Nairobi Hospital. It was carried out on all adult patients aged 18 years and above seen in the GIPAP clinic from 2007-2015 on follow-up for at least 36 months. The study population were patients diagnosed with CML, who developed cytopenia within 12 months of initiating imatinib mesylate. Baseline socio – demographic data, clinical data, hematologic data and molecular data were retrieved from charts of both cases and controls and entered into a predesigned study proforma. Analysis: For descriptive analysis, measures of central tendency were used (mean, median, mode, standard deviation and variance). For differences between groups, chi-square tests, ttests and ANOVA were used. To identify relationships, binary logistic regressions were employed. Univariate and multivariate analyses were done to identify independent predictors of cytopenia. Odds ratios (OR) were presented including the 95% confidence intervals and respective p values. Results: The results indicate that monocytopenia is the most common type of cytopenia at 63.6%. Anaemia was the most common type of mocytopenia at 34% whereas anaemia plus neutropenia was the most common bicytopenia at 12.7%. Pancytopenia was seen in only 5 out of the 94 patients. One half of the patients with any kind of cytopenia were at grade 2. The cytopenia developed within three months of initiating Imatinib and had resolved by 12 x months since initiation of Imatinib for anaemia and thrombocytopenia, and by month 24 for neutropenia. Baseline characteristics, time duration to diagnosis of CML, spleen size, presence of B symptoms and level of BCR-ABL1 were not found to be associated with development of cytopenia. A baseline thrombocytopenia and thrombocytosis, baseline neutropenia and a baseline anaemia were associated with increased odds of having cytopenia. Recommendations: the outcome of this study recommends that physicians should be more alert during hematologic monitoring of these patients. Our results also suggests that physicians to continue imatinib at 400 mg/day or at lower doses while supporting patients during the myelosuppression period due to the good recovery of cell counts during followup.