Adverse effects of imatinib in children with chronic myelogenous leukemia

Background Imatinib mesylate (IM) is a selective tyrosine kinase inhibitor and approved for indefinite treatment of pediatric CML. Potential side effects regarding growth failure and bone metabolism were reported, however, the data is still scattered in pediatric CML. Methods 6 chronic-phase CML children with the IM treatment with a median age of 9.87 years (range 5.33-12.67) were enrolled onto study. Growth, bone mineral density (BMD), bone parameters, 25(OH)-vitamin D3 (25-OHD3) and blood tests including parathyroid hormone (PTH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 3 (IGF-BP3), thyroid function test and sex hormones were assessed. Results The median duration of IM treatment was 78.5 months. Height velocity was suppressed during the first 30 months of treatment and improved gradually afterwards. Two patients (33.3%) had decreased lumbar spine BMD z-scores with <1.5 SD. Patients with decreased BMD had a higher mean IM exposure time than those with normal BMD. The majority of patients (five patients) had low 25-OHD3 levels (<30 ng/mL). However, there was no correlation between BMD and 25-OHD3 status. Other blood tests were normal. Conclusion This study supports and confirms the need for monitoring the side effects of IM treatment on growth, bone density and vitamin D status in pediatric CML. Prolonged IM treatment was associated with low BMD without disturbing bone parameters. There was high prevalence of vitamin D insufficiency. Therefore, the beneficial effect of vitamin D supplement should be explored regarding their effects on height velocity and BMD in CML patients with vitamin D insufficiency. This article is protected by copyright. All rights reserved.