A real-world study of inhaled corticosteroid 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 mepolizumab can reduce inhaled corticosteroid (ICS) use in these patients.

Objective: To investigate changes in ICS use and clinical outcomes in patients with SEA who initiated mepolizumab treatment.

Methods: This retrospective cohort study (GlaxoSmithKline identification: 212695/HO-20-19951) used administrative claims data from the IBM Watson Health MarketScan Database (identification period: November 2015 to March 2018). Eligible patients had SEA and were receiving high-dose ICS and mepolizumab. Use of ICS, oral corticosteroid (OCS), and short-acting β₂-agonist and exacerbation frequency were analyzed quarterly during the 12-month follow-up period after mepolizumab initiation.

Results: In total, 351 patients were included. The proportion of patients using high-dose ICS decreased in quarters 1 to 4 after mepolizumab initiation (79.8%, 74.6%, 68.9%, 65.5%, respectively); 49.0% of patients reduced or discontinued ICS for one or more quarter. Comparing patients who discontinued ICS vs 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 to 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 short-acting β₂-agonist 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.