OCT‐1 as a Determinant of Response to Antileukemic Treatment

Despite the excellent responses to imatinib therapy observed in patients with chronic phase chronic myeloid leukemia (CP‐CML), 1 ~25% of these patients demonstrate primary resistance or suboptimal response. 2 Inadequate inhibition of the kinase activity of BCR‐ABL 3 due to low intracellular concentrations of imatinib achieved in target leukemic cells has been associated with suboptimal response. 4 The organic cation transporter 1 (OCT‐1) has been identified as the major active influx pump for imatinib in CML cells, 4 , 5 and has therefore been investigated as a cause of suboptimal response in patients treated with imatinib. Clinical Pharmacology & Therapeutics (2011) 89 4, 608–611. doi: 10.1038/clpt.2011.12