The clinical relevance of imatinib plasma trough concentrations in chronic myeloid leukemia. A Belgian study (original) (raw)
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Introduction: Plasma imatinib levels vary widely in patients with the chronic myeloid leukemia‑chronic phase, and studies have shown improved hematological, cytogenetic, and molecular responses in patients with the higher trough imatinib levels. Materials and Methods: We analyzed 50 consecutive patients with the chronic myeloid leukemia‑chronic phase and performed plasma imatinib levels at 1 month and 12 months and correlated them with complete hematological response at 3 months and molecular response at 12 months, respectively. Results: Trough plasma imatinib levels at 1 month correlated well with complete hematological response at 3 months (P = 0.007) and levels at 12 months correlated with molecular response at 12 months (P = 0.04). Compliance to imatinib also significantly correlated with imatinib levels at 1 month (P = 0.0008) and imatinib levels at 12 months (P = 0.0002). Conclusion: Plasma imatinib levels may be of benefit in patients not achieving desired response at defined time intervals. The plasma level monitoring also helps in the assessment of drug compliance.
International Journal of Hematology, 2010
Despite the prognostic value of trough imatinib plasma levels (IPL) identified in some studies, no recommendations for the use of IPL results in routine management of CML patients have been issued. We report two patients in whom daily imatinib dose was increased from 400 to 600 or 800 mg because of low IPL found at various intervals from the beginning of treatment (7 measurements; mean IPL values = 616.33 and 764.5 ng/mL, respectively). Both patients achieved suboptimal response according to the European LeukemiaNet criteria (complete cytogenetic response was not achieved after 1 year of treatment in patient 1 and major molecular response after 47 months of standard-dose imatinib therapy in patient 2). In addition, we have demonstrated low hOCT-1 expression at diagnosis in both patients, retrospectively. Escalation of imatinib daily dose resulted in a significant increase of IPL (6 measurements; mean = 1790 and 1416.66 ng/mL, respectively) and in the achievement of complete cytogenetic response in patient 1 after 3 months and major molecular response within 15 and 6 months in both patients. Our cases demonstrate that low IPL identified at various non-predefined intervals from the beginning of therapy may be used for deciding on dose escalation in selected CML patients in the routine clinical setting, especially in cases with suboptimal treatment response.
Monitoring imatinib plasma concentrations in chronic myeloid leukemia
Rev Bras Hematol Hemoter, 2011
Imatinib has proved to be effective in the treatment of chronic myeloid leukemia, but plasma levels above 1,000 ng/mL must be achieved to optimize activity. Therapeutic drug monitoring of imatinib is useful for patients that do not present clinical response. There are several analytical methods to measure imatinib in biosamples, which are mainly based on liquid chromatography with mass spectrometric or diode array spectrophotometric detection. The former is preferred due to its lower cost and wider availability. The present manuscript presents a review of the clinical and analytical aspects of the therapeutic drug monitoring of imatinib in the treatment of chronic myeloid leukemia. The review includes references published over the last 10 years. There is evidence that the monitoring of plasmatic levels of imatinib is an useful alternative, especially considering the wide pharmacokinetic variability of this drug.
Hematological Oncology, 2013
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 C intrac 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 C intrac 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.
Annals of Hematology, 2012
Association of trough imatinib plasma levels (IPL) with cytogenetic or molecular response to treatment in patients with chronic myeloid leukemia (CML) was repeatedly reported. We analyzed their value in the routine clinical setting in 131 patients with chronic phase CML in whom imatinib was applied as first-or second-line treatment. A total of 1,118 measurements were obtained by ultraperformance liquid chromatography-tandem mass spectrometry assay in patients treated with daily dose of imatinib ranging from 100 to 800 mg. Samples were obtained from 1 to 96 h after drug ingestion. High inter (36%) and intraindividual variability (9-33%) of IPL was observed. For analysis of correlation of IPL with treatment response, two sets of samples were selected according to the European LeukemiaNet (ELN) criteria. The first set consisted of 241 samples taken 24±2 h after dosing in 54 patients, and the second one consisted of 329 samples taken 24±4 h after imatinib ingestion in 84 patients. In both sets, only patients treated with 400 mg imatinib once daily for at least 18 months were included. From multiple measurements in individual patients, mean IPL were used. In both sets, we were not able to demonstrate a statistically significant correlation between IPL and response to treatment according to the ELN. We believe that this was due to the differences in patients' compliance, leukemia biology, and other variables that are difficult to eliminate in the routine clinical practice. The use of IPL for prognostic estimation in CML treatment outside the clinical trials is probably limited.
Expert review of hematology, 2011
Suboptimal response or treatment failure to standard-dose imatinib are relevant problems in chronic-phase chronic myeloid leukemia patients. Insufficient adherence is one of the main causes of insufficient response but biological reasons also have to be considered. Various mechanisms of resistance have been described in the past, some of them mediating absolute resistance and others, relative resistance, to imatinib. The latter can be overcome by dose intensification of imatinib. However, the availability of second-generation tyrosine kinase inhibitors means these patients can be switched to these novel agents. Thus, which strategy is most appropriate for the individual patient with insufficient response to standard-dose imatinib remains elusive. Moreover, it remains unclear whether dose intensification of imatinib in the first-line setting might allow a more rapid and deeper response rate. This article will summarize data on imatinib dose intensification and will make recommendatio...
Annals of Hematology, 2016
To determine whether a lower imatinib dose could minimize toxicity while maintaining the molecular response (MR), imatinib dose was reduced to 300 mg daily in 43 patients with chronic myeloid leukemia (CML) in sustained deep molecular response to first-line imatinib 400 mg daily. At the time of dose reduction, median duration of the deep response was 4.1 (interquartile range (IQR) 2.2-5.9) years; molecular response was MR 4 , MR 4.5 , and MR 5 of the international scale in 6, 28, and 9 patients, respectively. Toxicity grade was 1, 2, and 3 in 28, 8, and 1 patients, respectively; 6 patients underwent dose reduction without having side effects. With a median of 1.6 (IQR 0.7-3.2) years on imatinib 300 mg daily, only one patient lost the deep molecular response to MR 3. At the last follow-up, response was MR 3 , MR 4 , MR 4.5 , and MR 5 in 1, 3, 9, and 30 patients, respectively. Toxicity improvement was observed in 23 (62.2 %) of the 37 patients with side effects, decreasing to grade 0 in 20 of them. All but one anemic patients improved (p = 0.01), the median Hb increase in this subgroup of patients being 1 g/ dL. In CML patients with sustained deep response to the standard imatinib dose, reducing to 300 mg daily significantly improves tolerability and preserves efficacy.