A real-world study of ICS use in patients with severe eosinophilic asthma treated with mepolizumab.

Background Mepolizumab is a humanized anti–interleukin-5 monoclonal antibody approved for the treatment of patients with severe eosinophilic asthma (SEA). There is limited evidence that patients treated with mepolizumab can reduce inhaled corticosteroid (ICS) use. Objective To investigate changes in ICS use and clinical outcomes in patients with SEA who initiated mepolizumab treatment. Methods This retrospective cohort study (GSK ID: 212695/HO-20-19951) used administrative claims data from the IBM Watson Health MarketScan Database (identification period: November 2015–March 2018). Eligible patients had SEA and were receiving high-dose ICS and mepolizumab. ICS, oral corticosteroid (OCS), short acting β2-agonist (SABA) use, and exacerbation frequency were analyzed quarterly during the 12-month follow-up period following mepolizumab initiation. Results In total, 351 patients were included. The proportion of patients using highdose ICS decreased in quarters 1–4 following mepolizumab initiation (79.8%, 74.6%, 68.9%, 65.5%, respectively); 49.0% of patients reduced or discontinued ICS for ≥1 quarter. Comparing patients who discontinued ICS versus those who remained on high-dose ICS, a lower proportion had chronic OCS use (3.4–9.2% vs 13.9–16.8%) and OCS burst use (15.4–20.8% vs 19.7–26.1%) in quarters 1–4; similarly in quarters 3 and 4, a lower proportion of patients had exacerbations (16.9% and 20.3% vs 27.2% and 27.7%) and SABA claims (35.4% and 39.2% vs 43.3% and 49.0%, respectively). Conclusion: In patients with SEA on high-dose ICS, a reduction in both ICS and OCS use was observed after initiating mepolizumab. These findings have important implications for clinical outcomes and follow-up care in this patient population.