No clinical evidence for performing trough plasma and intracellular imatinib concentrations monitoring in patients with chronic myelogenous leukaemia

This multicentre study focused on monitoring imatinib mesylate (IMA) trough plasma (C-trough) and intracellular (IMA C-intrac) concentrations in 228 chronic myelogenous leukaemia patients. The median of measured IMA C-trough in our patient group was 905.8 ng ml (range: 27.7-4628.1 ng/ml). We found a correlation between IMA C-trough and alpha 1-acid glycoprotein plasma concentrations (rS=0.42; p<0.001). All other analysed parameters revealed only weak (gender, dose of IMA per kg) or not significant (age, albumin, creatinine plasma concentration or body mass index) impact on measured IMA C-trough. The IMA C-trough decreased during the first 6 months and significantly increased later during treatment. The IMA C-trough at the first month of therapy did not differ between patients with and without an optimal response at the 12th (p = 0.724) and 18th month (p = 0.135) of therapy. There were no significant differences in medians of IMA C-trough between both groups measured during the first year of treatment. The IMA Cintrac during the first month were not different between patients with and without an optimal response at the 6th (p = 0.273) and the 12th month (p = 0.193) of therapy. Our data obtained from real life clinical practice did not find a benefit of routine and regular IMA C-trough nor IMA Cintrac therapeutic drug monitoring in chronic myelogenous leukaemia patients or for subsequent adjustments of the IMA dose based on these results. Moreover, actual alpha 1-acid glycoprotein plasma concentration should be used for proper interpretation of IMA C-trough results. Copyright (C) 2013 John Wiley & Sons, Ltd.