Utility of the trough plasma imatinib level monitoring at two time points in patients with the chronic myeloid leukemia-chronic phase

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.