Real-world outcomes of mepolizumab in severe eosinophilic asthma: a retrospective cohort study

Objective: To evaluate the efficacy and safety of mepolizumab in patients with severe eosinophilic asthma (SEA) in a real-world clinical setting. Methods: This retrospective, observational cohort study included data from 45 SEA patients who initiated mepolizumab treatment, with 41 completing a 12-month follow-up. Demographic, clinical, and laboratory data-including exacerbation rates, forced expiratory volume in one second (FEV1), Asthma Control Test (ACT) and CARAT scores, and blood eosinophil counts-were extracted from patient medical records. Paired statistical tests were used to compare pre- and post-treatment outcomes, with significance set at p < 0.05. Results: Mepolizumab therapy was associated with an 81% reduction in annual exacerbation rates (from 2.68 to 0.51 events; p < 0.001) and a 21.6% improvement in FEV1 (from 1.71 L to 2.08 L; p < 0.001). ACT scores increased significantly from 11.91 to 21.29 (p < 0.001), with 73.2% of patients achieving well-controlled asthma (ACT = 20). CARAT scores also showed significant improvement, reflecting better control of both asthma and rhinitis symptoms. Blood eosinophil counts decreased by 64% (from 525.9 to 189.4 cells/µL; p < 0.001). Overall, the treatment was well tolerated, with only one discontinuation due to a mild headache. Conclusion: In this real-world cohort, mepolizumab significantly reduced exacerbation frequency, improved lung function and symptom control, and lowered eosinophil levels over 12 months. These findings support its use as an effective and safe therapeutic option for managing severe eosinophilic asthma.