Effectiveness of mepolizumab therapy on symptoms, asthma exacerbations, steroid dependence, and small airways in patients with severe eosinophilic asthma

Background/aim: The efficacy of mepolizumab has been largely demonstrated in clinical trials in patients with severe eosinophilic asthma (SEA). However, reports on experience with mepolizumab in a real-life cohort are limited. Moreover, data about the effectiveness of mepolizumab on small airways is scarce. This study evaluated the effectiveness of mepolizumab therapy on symptoms, asthma exacerbations, blood eosinophils, steroid dependence, and small airways in a real-life cohort of patients with SEA. Materials and methods: We retrospectively analyzed patients with SEA who were receiving fixed-dose mepolizumab. The effects of mepolizumab on clinical, laboratory, functional parameters were evaluated at 12th, 24th, and 52nd weeks. Small airways were assessed with the FEF 25-75. Results: A total of 41 patients were enrolled in the study. Mepolizumab significantly reduced asthma exacerbation rates, reduced mOCS dose, and improved asthma control test (ACT) scores at 12th, 24th, and 52nd weeks. However, we found no significant changes in FEV1 and FEF25-75 values at baseline, 12th, 24th, and 52nd weeks (78.9 ± 23.3%, 82.9 ± 23.4%, 81.9 ± 23.9%, and 78.9 ± 23.5% for FEV1; 45.1 ± 23.1%, 48.8 ± 23.5%, 48.7 ± 23.1%, and 41.0 ± 20.1% for FEF25-75, respectively) Conclusion: In this study, mepolizumab significantly improved all outcomes (symptom scores, asthma exacerbations, OCS sparing, and blood eosinophils) except functional parameters. Still, despite the dose reduction in mOCS dosage, no significant deterioration was observed in FEV1 and FEF25-75 values.