Upon treatment with imatinib, most patients restore normal hematopoiesis (Hochhaus et al., 2018). The long-term efficacy and safety imatinib in CML patients in the chronic phase have been established in IRIS Study (Hehlmann et al., 2017; Hochhaus et al., 2017; Hochhaus et al., 2018). After almost 11 years of follow-up, overall survival at ten years in imatinib-treated patients was 83.3% with no notable toxic effects (Hochhaus et al., 2017). Nonetheless, about 20-30 % of CML patients failed

Herbal medicines have long been used for traditional treatment of diseases. Our ancestors used plants empirically as treatment and for the maintenance of health inherited from generation to generation. At present, most of the research and development of drugs is still focused on a single compound as the main compound against the treatment target. It is difficult to get a single compound chemical with high selectivity and potential but low toxicity to the target of the disease. Empiric treatment with medicinal plants is particularly a concern in cancer treatment, where treatment is currently done with chemotherapy, radiotherapy, and surgery. The active compound of herbal plants is one alternative in searching for a new anti-cancer because it is believed to have minimal side effects. Therefore, the design and development of anti-cancer drug candidate from herbal plants are increasingly in demand.

Background: Imatinib mesylate is the first tyrosine kinase inhibitor approved for chronic myeloid leukemia (CML) therapy. Imatinib is an effective drug. However, previous studies have shown that about 20-30% of patients eventually would develop resistance to imatinib. Approximately 40% of imatinib resistance is associated with BCRABL kinase domain mutation. One of the most common and serious variations account for imatinib response is T315I of ABL1 gene. Objective: The study aimed to examine the association of T315I mutation with the ABL1 gene and its relation to major molecular response (MMR) achievement in CML patients. This study also examined other mutations adjacent to T315I, i.e., F311I, F317L, and different possible variations in the ABL1 gene. Methods: This was a cross-sectional study on Indonesian CML patients in chronic phase. We analyzed 120 blood samples from patients in chronic phase who have received imatinib mesylate (IM) for ≥12 months. Results: There were no T315I, F311I, and F317L mutations found in this study. However, we found another variation, which was 36 substitutions from A to G at position 163816 of ABL1 gene (according to NG_012034.1). Conclusions: We found no T315I, F311I, and F317L mutations in this study. Our findings suggest that there might be other factors that influenced the MMR achievement in our study patients. However, there were 36 substitutions from A to G at position 163.816 (according to NG_012034.1) that needed further examination to explore the significance of this mutation in clinical practice.