Pb1986: first-line treatment outcomes of chronic myeloid leukemia (cml) patients in a real-world data setting in lebanon

Topic: 8. Chronic myeloid leukemia - Clinical Background: BCR–ABL-targeting tyrosine kinase inhibitors (TKIs) constitute the cornerstone of treatment for CML, leading to a life expectancy that is currently very close to that of age-matched individuals in the general population. Aims: This study aims to describe aspects of CML in a real-world data setting in Lebanon, including responses to first-line treatment with the first-generation TKI imatinib compared to those with the second-generation TKIs dasatinib and nilotinib, and to evaluate the proportion of patients eligible for an attempt to stop TKI treatment. Methods: This is a retrospective observational multi-center study involving Lebanese patients diagnosed with CML between 2003 and 2019. Inclusion criteria were patients older than 18 years, confirmed diagnosis with CML based on BCR-ABL PCR, and available follow-up data in the clinical chart for at least 2 years. Major and deep molecular responses were based on BCR-ABL1 levels; time of attaining these responses and duration of sustained responses were measured. The reason for switching to another TKI was noted (‘treatment failure’ or ‘intolerance’). Eligibility criteria for an attempt to stop TKI were based on the EURO-SKI trial. Imatinib was given at a dose of 400 mg once daily, nilotinib 300 mg twice daily, and dasatinib 100 mg once daily. The choice of treatment was at the discretion of the treating physician in consultation with the patient as per respective financial and supportive care status. SPSS was used for statistical analysis. Results: 54 patients diagnosed with CML between 2003 and 2019. 54 % were males. The median age at diagnosis was 49.00 ± 17.75 years. The most common reason for presentation was incidental leukocytosis (90%). 70% of patients were treated with imatinib and 30% with a second-generation TKI. 14% of patients discontinued their first-line treatment, mainly due to intolerance (10%) or treatment failure (5%). At 24 months, deep molecular response MR4.0 and MR4.5 was achieved at 15.3% and 40.3%, respectively, for imatinib, and 22% and 33.5%, respectively, for second-generation (p=1). Cumulative incidence of MMR at 24 months of treatment reached 88.9%. The 5-year cumulative incidence of eligibility for TKI cessation attempt was 37%. Summary/Conclusion: We report the experience in CML from two health care institutions in Beirut, Lebanon. There was no statistically significant difference in response between the first- and second-generation TKIs. The criteria for an attempt to stop TKI therapy were met by one-third of patients. Keywords: Survival, BCR-ABL, Chronic myeloid leukemia, Real world data