A lower dosage of imatinib is sufficient to maintain undetectable disease in patients with chronic myeloid leukemia with long-term low-grade toxicity of the treatment

Abstract

The information about chronic myeloid leukemia (CML) patients with a deep molecular response of ≥ 4.5 log reduction (MR^4.5) in whom the dose of imatinib (IM) had to be reduced to relieve toxicity is insufficient. In 205 CML patients the dose of IM was reduced in 19 (31.2%) out of 61 patients with MR^4.5. The patients (12 pretreated with interferon-alpha) achieved MR^4.5 after an average of 27.7 months. The duration of MR^4.5 before the reduction of the dose was 16–123 (mean = 56.7) months. After the IM reduction (200 mg daily to 400 mg twice weekly for 15–90 (mean = 48) months) MR^4.5 or major molecular response (MMR) was maintained in 14 (73.7%) and 2 (10.5%) patients, respectively. Three patients who lost MMR (15.8%) after the discontinuation of IM regained MR^4.5 after the reintroduction of a lower dose. A lower dosage of IM should be tested for the management of side effects in patients with MR^4.5 in prospective studies.

Keywords::

• Chronic myeloid leukemia
• imatinib
• minimal residual disease
• side effects

Acknowledgements

We are grateful to Pavel Kurfürst and Simon Gill for editorial help.

This work was supported by grants IGA MZ ČR NT12218-4/2011 and IGA-LF-2015-001 Palacky University. The infrastructural part of this project (Institute of Molecular and Translational Medicine) was funded by the Operational Program Research and Development for Innovations (project CZ.1.05/2.1.00/01.0030).

Potential conflict of interest

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