Switching Things Up: Experience of Second Line Anti-Interleukin-5 Therapy for Severe Asthma

Introduction: A significant proportion of severe asthma patients switch Monoclonal Antibodies (mAbs) if initial response is sub-optimal. Mepolizumab (M) and Benralizumab (B) target interleukin 5 (IL5) and IL5-receptors respectively. Literature describing outcomes of switching between these agents is minimal. (Papaioannou, A. et al. Clin Exp Allergy. 2021;51(2):221-227). We describe outcomes of patients switching anti-IL5 agents. Methods: Retrospective review of patients switched to alternative mAb due to poor clinical response to M or B, assessing physiological parameters, quality of life, and outcomes. Patient were either changed to the same class (different anti-IL5) or another class. Results: Of 30 (B n=5, M n=25) patients, 21 (B n=1, M n=20) switched to a second anti-IL5 agent, and 9 switched to Dupilumab. Baseline characteristics/comorbidities did not differ significantly between groups. Following switch, the anti-IL5 group had a significantly lower eosinophil count (EC) (0.005±0.02 v 0.48±0.38, p<0.001). Other parameters were not significantly different. 8/21 of the anti-IL5 group failed 2nd-line therapy, compared to 4/10 of the non-anti-IL5 group. Conclusion: Patients who switch between anti-IL5 agents have similar clinical outcomes to those who switch to a non-anti-IL5 agent. While further research is needed, these results suggest that it is worth trialling alternative anti-IL5 treatments in those who have sub-optimal response.