Trends in Medicare versus Medicaid spending on CFTR modulator therapy - an economic evaluation

The introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators has changed the landscape of therapy for persons with cystic fibrosis. However, the steep cost of targeted therapy poses significant financial burden for individuals and health systems. We aimed to determine the trends in Medicare and Medicaid spending on CFTR modulators between the years 2015 and 2022 through retrospective analysis of the Medicare and Medicaid claims data. The outcome measures included total dosage units prescribed, number of claims, spending per claim, and total spending on CFTR modulators for Medicare and Medicaid between 2015 to 2022. Average annual percentage changes (AAPC) were calculated for all outcome measures. Our results show that from 2015 to 2022, Medicaid consistently had higher total dosage units prescribed, number of claims, spending per claim, and overall spending on CFTR modulators compared to Medicare. Total spending for both Medicaid [AAPC 38.9, 95 % confidence interval [CI] 27.2-51.6, p < 0.01] and Medicare [AAPC 39.2, 95 % CI 30.2-55.1, p < 0.01] increased significantly during this period. Increases in CFTR spending was accelerated beginning in 2019, when the triple combination CFTR modulator therapy, elexacaftor/tezacaftor/ivacaftor, was introduced to the US market. This increase has been accompanied by a reduction in spending and use of other CFTR agents. This study evaluated the increases in spending for CFTR modulators over the years and the main drivers behind them, which may help inform future negotiations between healthcare systems and pharmaceutical companies, as well as policy makers and stakeholders.