Mepolizumab in Severe Pediatric Asthma: Certainties and Doubts through a Single-Center Experience and Review of the Literature

Background: Although, in most children with asthma, good symptom control is achieved with a low to moderate dose of inhaled corticosteroids, a small group of patients still experiences frequent symptoms, and even severe exacerbations, impairment of lung function, and reduced quality of life. Some of these subjects with severe asthma require biologic drugs as add-on therapy. In the past decade, numerous monoclonal antibodies have been approved for children or adolescents with severe asthma, in addition to their increasing use in adult asthma. However, the available evidence on how to select the most appropriate biologic based on a single patient's clinical, functional, and laboratory characteristics is still scant, and is insufficient to guide clinicians in the decision-making process of a personalized treatment. Materials and Methods: We report a case series of four patients with severe eosinophilic asthma treated with mepolizumab, an anti-interleukin-5 monoclonal antibody, and review the existing literature on this treatment in children and adolescents. Results: Our patients, all with blood eosinophilia and elevated fractional exhaled nitric oxide levels, developed poor symptom control despite prolonged treatment with high-dose inhaled corticosteroids plus a second controller, addressing the addition of a biologic drug. In all of them, a 12-month treatment with subcutaneous mepolizumab showed a reduction in the blood eosinophil count and in asthma exacerbations, as well as an improvement on the Asthma Control Test. The results of the literature search focused on the strengths and limitations of the pediatric use of mepolizumab and highlighted the areas worthy of further research. Conclusions: Mepolizumab has proven effective in improving symptom control in pediatric patients with severe asthma. Additional well-powered clinical trials will be helpful in developing evidence-based guidelines regarding biologic drugs in the pediatric population.