Therapeutic Switching of Biological Drugs in Paediatric Severe Asthma: Experience of a Referral Centre.

Background/Objectives: Biologic therapies are the cornerstone of severe asthma management. However, evidence regarding switching between biologics in children with severe asthma remains limited. Methods: Retrospective observational study including patients aged 6-17 years with severe asthma, followed at our tertiary referral center, who switched biologic therapy. Clinical, laboratory, and lung function data were collected at the initiation of the second biologic (T0) and after 4 (T1) and 12 months (T2). Changes in asthma control, exacerbation rate, inhaled corticosteroid dose, FeNO and lung function were evaluated. Results: Eight patients who switched and had been treated with a second biologic for at least 12 months were included. Switching occurred from omalizumab to dupilumab (n = 1), mepolizumab to dupilumab (n = 5), and mepolizumab to omalizumab (n = 2). The main reason for switching was inadequate asthma control, while one patient switched because of poorly controlled comorbidity. At T2, exacerbations significantly decreased (p = 0.03), with significant improvements in FEV1 (p = 0.002) and FEV1/FVC (p = 0.015). The daily fluticasone-equivalent dose decreased from a median of 500 μg to 425 μg. Conclusions: In this cohort, switching biologic therapy was associated with improved clinical and functional outcomes, with a significant response already detectable after 4 months. These findings highlight the importance of close clinical and functional monitoring to identify children who may benefit from a change in biologic therapy. Larger prospective studies are needed to define standardized criteria and optimal timing for biologic switching in pediatric severe asthma.