S87 Severe asthma outcomes when switching from mepolizumab to benralizumab in non-responders with persistent sputum eosinophilia

<h3>Background</h3> Anti-IL-5 monoclonal antibodies reduce systemic corticosteroid use and exacerbation rate in severe eosinophilic asthma. Although their specific mechanisms of action differ, there is as yet no guidance on whether to choose mepolizumab or benralizumab for any given patient. <h3>Aims</h3> To investigate clinical outcomes of patients switching to benralizumab after non-response to mepolizumab associated with persistent sputum eosinophilia. <h3>Methods</h3> We recruited patients who failed to respond to mepolizumab over 12 months (no meaningful reduction in maintenance steroid use and/or exacerbation rate), with sputum eosinophils above the threshold of 2%. Over the subsequent 12 months of benralizumab treatment we recorded daily prednisolone dose, ACQ6, AQLQ, and sputum &amp; blood eosinophils. Lung function and FeNO testing was severely impacted by the COVID pandemic. <h3>Results</h3> Fifty-three of 165 (32%) mepolizumab patients were identified as candidates for a switch of therapy with residual positive sputum eosinophils, of which 36 have completed 12 months of treatment, 20 with available sputum eosinophil results. Five patients stopped therapy before a full year (two for failure to respond to treatment at 6–9 months, one allergic reaction, two unspecified). After 12 months on benralizumab, all patients had negative sputum eosinophils as well as improvements in ACQ6, AQLQ, blood eosinophils and reduced exacerbation rate compared to before switching (table 1). <h3>Conclusions</h3> Around a third of patients failed to respond to mepolizumab and displayed persistent airway eosinophilia. All of these patients had complete suppression of sputum eosinophils on benralizumab with significant clinical improvements in exacerbation rate, blood eosinophils, asthma control and quality of life. These real-life observations in our severe asthma patient population confirm the results of the SIROCCO and Calima trials.