Real-World Effectiveness and Safety of Mepolizumab in Pediatric Severe Eosinophilic Asthma: A Multicenter Study

Severe asthma (SA) in children is a complex condition with high morbidity and healthcare costs. Mepolizumab, an anti-interleukin-5 biologic, is approved for severe eosinophilic asthma (SEA) in patients ≥ 6 years, yet long-term real-world pediatric data remain limited.

To assess the long-term safety and effectiveness of mepolizumab in pediatric SEA, focusing on lung function, oral corticosteroid (OCS) use, and exacerbation rates.

This retrospective, multicenter study examined the medical records of 33 patients with SEA (aged 6-17 years) who received mepolizumab treatment at three tertiary centers in Turkiye. Inclusion criteria included GINA-defined SA, ≥ 2 severe exacerbations in the previous year requiring OCS, high-dose ICS plus a second controller, and elevated eosinophil counts. Data on exacerbations, pulmonary function tests (PFTs), OCS use, ACT scores, eosinophils, and adverse events were collected over 24 months.

At baseline, patients showed poor asthma control (median ACT: 13), impaired lung function (FEV1%: 62%), and frequent exacerbations (median: 7/year). Mepolizumab significantly reduced exacerbation rates (median: 7 to 0-0.05 at 12/24 months, p = 0.005) and OCS use (87.9% OCS-free by 3 months). ACT scores improved (median: 13-25, p < 0.001), as did FEV1% (62% to 89%, p < 0.001) at 24 months. Eosinophil counts decreased markedly (460 to 50 cells/µL, p < 0.001). The treatment was well-tolerated; one patient discontinued due to anaphylaxis and four due to lack of efficacy.

Mepolizumab showed sustained effectiveness and good tolerability in pediatric SEA, significantly reducing exacerbations and OCS use while improving asthma control and lung function. These findings support its real-world utility and underscore the need for careful patient selection and monitoring.