Real-World Comparative Effectiveness of Mepolizumab versus Benralizumab in an Older Population with Asthma: A US Medicare Fee-for-Service Analysis

Guillaume Germain,1 Emmeline Burrows,2 Jacob Klimek,3 Patrick Gravelle,4 Kioumars Tavakoli Tafti,1 François Laliberté,1 Arijita Deb51Group d’analyse SRI, Montréal, Québec, Canada; 2US Medical Affairs, GSK, Durham, NC, USA; 3Analysis Group, Inc, Boston, MA, USA; 4Analysis Group ULC, Toronto, Ontario, Canada; 5Global Real-World Evidence & Health Outcomes Research, GSK, Upper Providence, PA, USACorrespondence: Arijita Deb, Global Real-World Evidence & Health Outcomes Research, GSK, Upper Providence, PA, USA, Tel +1 267 377-5717, Email arijita.x.deb@gsk.comBackground: Biologic therapies, including mepolizumab and benralizumab, are used to treat uncontrolled asthma. However, real-world evidence comparing these treatments is limited. This study compared asthma-related hospitalizations and asthma exacerbations between mepolizumab and benralizumab among Medicare fee-for-service (FFS) beneficiaries with asthma.Methods: Data were obtained from Komodo Research Database (01/01/2018-05/31/2025). Eligible patients included Medicare FFS beneficiaries with asthma and a first claim for mepolizumab or benralizumab on or after January 1, 2019 (index date). An adherent subgroup included those who remained adherent to their index biologic for ≥ 6 months. Overlap weighting based on a propensity score model was used to balance cohorts. Asthma-related hospitalizations and asthma exacerbations were evaluated while on treatment. Rates were reported as the number of events per-patient-year (PPY) and compared between weighted cohorts using rate ratios (RRs) with 95% confidence intervals (CIs). Non-inferiority using a fixed-margin approach was used to compare rates of asthma-related hospitalizations between cohorts.Results: In total, 125 and 177 patients were included in the mepolizumab and benralizumab cohorts, respectively (mean age: 70.7 years, 69.1 years). After weighting, baseline characteristics were well-balanced. At 1-year post-index, mepolizumab demonstrated superiority over benralizumab for asthma-related hospitalizations, showing a 77% rate reduction (0.036 PPY vs 0.155 PPY; RR: 0.23, 95% CI: 0.07, 0.74; p=0.013) and was associated with comparable rates of asthma exacerbations (1.056 PPY vs 1.302 PPY; RR: 0.81, 95% CI: 0.52, 1.26; p=0.348). In the adherent subgroup, mepolizumab remained superior to benralizumab for asthma-related hospitalizations (0.040 PPY vs 0.167 PPY; RR: 0.24, 95% CI: 0.07, 0.79; p=0.019) and remained associated with comparable rates of asthma exacerbations (0.927 PPY vs 1.249 PPY; RR: 0.74, 95% CI: 0.44, 1.25; p=0.265). Consistent results were observed at 2-years post-index.Conclusion: Mepolizumab was superior to benralizumab for asthma-related hospitalizations, while asthma exacerbation rates were comparable between the two therapies.Keywords: asthma, benralizumab, biologic therapy, medicare, mepolizumab, real-world evidence