5PSQ-021 Abstract withdrawn

<h3>Background and Importance</h3> Most data on switching monoclonal antibodies come from real-life studies. Switching is recommended when current treatment is insufficient. Patients who switch often have higher baseline eosinophil counts and exacerbation rates, despite oral corticosteroid (OCS) dependence. <h3>Aim and Objectives</h3> To describe the use of biologics in patients with severe asthma, focusing on treatment persistence, switching to other biologics, and the relationship to asthma outcomes. <h3>Material and Methods</h3> Multicentre retrospective, observational study that included patients with severe allergic or mixed asthma treated with at least two biologics between January and September 2024. Qualitative variables: age, sex, asthma type, smoking status, comorbidities, prior oral corticosteroids (OCS), first-line biologics, adherence, reasons for switching, second-line biologics, emergency room (ER) visits, hospitalisations, third or fourth-line treatments. Quantitative variables: body mass index (BMI), age, treatment median duration, time to ER visit after switching, IgE, eosinophils, FVC, FEV1, and FVC/FEV1 ratios at baseline and at 16,32 and 48 weeks. Data analysis was performed using R Commander. <h3>Results</h3> A total of 48 patients were analysed, with 45.8% male and a median age of 57 years. Most had mixed asthma (60.4%) and a median BMI of 28.3. Of the patients, 52% were non-smokers, 40% were ex-smokers, and 8% were smokers. Comorbidities included rhinitis 35.4%), rhinosinusitis (31.2%), nasal polyps (25%), and chronic obstructive pulmonary disease (COPD) (10.4%). All patients had used inhaled therapy, and 79% OCS. Initial biologics included omalizumab (83.3%), benralizumab (8.3%), mepolizumab (6.2%), and dupilumab (2.2%). All switched due to poor control, exacerbations, or adverse effects. Second-line biologics were benralizumab (35.4%), dupilumab (33.3%), mepolizumab (27%), and tezepelumab (4.3%). During this phase, 25% visited the ER, and four were hospitalised. Nine patients required a third-line therapy, primarily dupilumab (44.4%) and benralizumab (33.3%). Omalizumab was reintroduced in two patients due to insufficient response to other treatments. <h3>Conclusion and Relevance</h3> Selecting the most suitable treatment depends on the patient’s clinical history, biomarkers and comorbidities. Further studies are needed to characterise which patients benefit the most from biologics in severe asthma to minimise the need for switching. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest