Chronic Myeloid Leukemia in Bulgaria in the New Millennium: Identification of Directions for Improvement in Management and Outcomes Reporting

Abstract

Background: In the last two decades, tyrosine kinase inhibitors (TKIs) and advances in molecular diagnostics have revolutionized management and long-term clinical outcomes in chronic myeloid leukemia (CML). Real-world data from different countries allow for the identification of country-specific issues in the clinical management and development of specific plans for improvement. Here, we aimed to analyze the trend in overall survival in Bulgarian CML patients since 2000. Methods: We retrieved publicly available Bulgarian CML data from several sources such as the Bulgarian National Cancer Registry, Bulgarian National Statistical Institute, and National Health Insurance Fund since 2000. We used the retrieved data of a total of 1513 Bulgarian CML patients to describe the trends in overall survival (OS), conditional overall survival, life expectancy, and life years lost over five time periods. We also described the trends in healthcare expenditures for TKIs and CML patients’ coverage with TKIs since 2014. Results: In both uni- and multivariate models, we found a constant increase in OS over the three 5-year periods until 2014. The period 2015–2019 was not associated with an additional increase in OS. Identical dynamics in the improvement in life expectancy (LE) and in life years lost (LYLs) was observed. Additionally, conditional 5-year survival did not improve during 2015–2019 in comparison to 2010–2014. Population-level data did not show consistent changes in the documented number of deaths due to CML since 2013. The period after 2013 is marked by a constant increase in the annual expenditures for TKIs, reaching to about 2.0 EUR/capita. The number of patients who received at least one TKI also increased during that period. Conclusions: After the initial significant improvement in the clinical outcomes for Bulgarian CML patients until 2014, subsequent periods did not bring further benefit in spite of the improved coverage with second- and third-line TKIs. Multiple factors may contribute to these suboptimal outcomes. Therefore, one can propose several additional measures at the country level, which could lead to additional improvement in the OS of Bulgarian CML patients.