Pharmacogenomics Validation for Imatinib in Chronic Myeloid Leukemia

• The activity of Imatinib(IM) is mediated by blocking the activity of BCR/ABL tyrosine kinase in CML cells. However, some of the patients failed to achieve optimal response, and a substantial proportion of patients develop resistance to IM.
• IM is a substrate for the adenosine triphosphate binding cassette (ABC) transporters, ABCB1 and ABCG2, while the active uptake of IM into cells is mediated by the human organic cationic transporter-1 (hOCT1). Also, IM is metabolized through first pass drug metabolism by the cytochrome P450 - CYP3A4 and CYP3A5. In addition, it is delivered in a bound form with a plasma protein referred to α1-acid glycoprotein (AGP).
• Accordingly, the intracellular or systemic level of imatinib should be influenced by these factors such as ABCB1, ABCG2, hOCT1, CYP3A4, CYP3A5 or AGP genes. Inter-individual variability of 5 candidate genes associated with drug transport/metabolism (i.e. ABCB1, ABCG2, hOCT1, CYP3A4/3A5 and AGP) could affect the expression of corresponding proteins, thus influencing the treatment outcomes of imatinib therapy.
• In the investigators' previous study, the investigators reported the cumulative incidences of MCyR and CCyR was significantly affected by the predictive model using 2 genotypes and disease stage. These predictive models for CCyR/MMoR or LOR/treatment failure seemed to work well. However, external validation of these predictive models is warranted especially using ethnically different independent cohort.

Inclusion criteria

• Chronic myeloid leukemia of any stage including chronic phase, accelerated or blastic phase.
• Age>18 years
• Complete set of clinical data available for review (demographic data, stage, treatment history, cytogenetic reports, and latest BCR/ABL RQ-PCR results)
• Treated with imatinib mesylate at least 3 months

Exclusion criteria

• Treated with imatinib mesylate less than 3 months
• Not agree with the intention of this study