Pb1983: relationship between regular molecular monitoring and treatment outcomes in cml patients in armenia

Topic: 8. Chronic myeloid leukemia - Clinical Background: Treatment with tyrosine kinase inhibitors (TKIs) and regular molecular monitoring to assess the deep molecular response (DMR) offer good opportunities for achieving treatment-free remission (TFR) in patients with chronic myeloid leukemia (CML) (1). In Armenia, CML patients have been treated with Imatinib since December 2003, Ponatinib and Nilotinib have been available since 2018, and regular qRT-PCR monitoring started in January 2021 (2,3). 5-year overall survival (OS) is 92%, which is similar to other countries, and the incidence is increasing per year reaching to 0.9:100000 for 2018 (2, 4). Aims: This retrospective study aims to evaluate how regular molecular monitoring and early treatment changes between TKI generations has influence on treatment outcomes, and, additionally, to show CML treatment effectiveness with TKIs in Armenian population. Methods: The data was taken from the department of Molecular Biology of Hematology Center, Armenian CML Research Group database and “The Max Foundation” website. TKIs and PCR kits were donated by “The Max Foundation”. Statistical analysis was performed by SPSS 22 software. To estimate the difference of BCR/ABL % before and after the treatment, Wilcoxon’s non paramedic test was used. Results: The first control PCR was performed in 225 patients, of which the second PCR was performed in 129, the third in 40, the fourth in 18, the fifth in 6, and the sixth in 3. 100% of patients received primary therapy with Imatinib. According to the first PCR results, 35 patients (15.6%) achieved major molecular response (MMR) through Imatinib therapy, 21 patients (9.3%) reached molecular remission 4 (MR4), and 67 patients (29.8%) reached molecular remission 5 (MR5). After the first molecular control Imatinib was switched to Nilotinib in 18 patients, 2 of which were later switched on Ponatinib. 4 patients changed Imatinib with Nilotinib after the second PCR, and 1 patient after the third PCR. Based on the PCR results, the treatment of 23 patients was replaced by the next generation TKI for the first time, and the other drug changes were performed due to the loss of hematological remission. Nilotinib was changed to Ponatinib in 2 patients after the first control PCR. 5 patients started Ponatinib after the 2nd control PCR, 1 patient after the 3rd PCR, and 1 patient after the 4th PCR. Significant difference was observed in case of any changes of TKI treatment (p < 0.001), and before and after changing Imatinib to Nilotinib (p < 0.003). Summary/Conclusion: To conclude, there is a significant effectiveness of TKI treatment among the Armenian population of patients with CML who have undergone regular PCR monitoring. Further analysis is needed to assess the likelihood of future TFR in CML patients in Armenia. References 1.Chen Y, Zou J, Cheng F, Li W. Treatment-free remission in chronic myeloid leukemia and new approaches by targeting leukemia stem cells. Frontiers in Oncology. 2021;11. 2.Harutyunyan L, Voskanyan A, Meliksetyan K, Sahakyan L, Chakmanyan A, Sargsyan G, et al. CML-307: Assessment of 5-year OS and treatment options in newly diagnosed Ph + CML patients in the Republic of Armenia. Clinical Lymphoma Myeloma and Leukemia. 2021;21. 3.Harutyunyan L, Ivanyan A, Ghazaryan N, Voskanyan A, Meliksetyan K, Ter-Grigoryan A, et al. Poster: CML-187 Association of Molecular Remission with Eutos and elts risk scores among CML patients in the Armenian cohort. Clinical Lymphoma Myeloma and Leukemia. 2022;22. 4.Harutyunyan L, Meliksetyan K, Ivanyan A, Hakobyan Y. CML-218: Primary diagnosed CML patient 5-year treatment outcomes and disease incidence in an Armenian population. Clinical Lymphoma Myeloma and Leukemia. 2020;20. Keywords: Chronic myeloid leukemia, Molecular response