Background: Imatinib mesylate is the first generation of Tyrosine kinase inhibitors (TKI) and highly effective in the treatment of chronic myeloid leukemia (CML). We aimed to evaluate thyroid function at baseline and at 1, 3, 6 and 12 months after initiation of Imatinib mesylate therapy in 20 newly diagnosed BCR-ABL positive CML patients.
Methods: This study was done during 2013-2014, 20 new cases with Philadelphia chromosome-positive CML without any underlying thyroid disorder or drug history interfering with Imatinib mesylate were enrolled. Thyroid function tests including serum Thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), anti-thyroid peroxidase (Anti-TPO) and anti-thyroglobulin (Anti-Tg) were assessed at baseline and during follow-up.
Results: Mean age at diagnosis was 60.4 years. 14 (70%) patients were male.  Mean value for TSH, FT4, FT3, Anti-TPO, and Anti-Tg before treatment were 2.82 mIU/L, 1.39 ng/dl, 325.50 ng/dl, 30.35 IU/ml and 39.40 IU/ml, respectively. The mean value for TSH, FT4, FT3 and Anti-TPO 1, 3, 6, and 12 months after initiation of Imatinib mesylate were not statistically significant.
Conclusion: Based on the results of the study, there was no significant change in thyroid function tests during treatment with Imatinib mesylate and all laboratory variables were in normal ranges.