Long-Term Effectiveness of Anti-IL4R Therapy Following Suboptimal Response to Anti-IL5/5R Therapy in Severe Eosinophilic Asthma

Background Dupilumab is an anti-IL4R monoclonal antibody (mAb) with proven efficacy in severe eosinophilic asthma (SEA). A suboptimal response to anti-IL5/5R mAbs is seen in some patients with ongoing evidence of T2 inflammation. Objective To understand whether targeting IL-13 pathways with dupilumab in these patients may lead to better clinical outcomes. Methods We performed a retrospective analysis of the extended clinical effectiveness of dupilumab up to 2 years of treatment in patients with SEA who had not responded adequately to anti-IL5/5R biologics. Ability to achieve clinical remission and change in the remission domains of exacerbation rate (AER), maintenance oral corticosteroid dose (mOCS), lung function (FEV1) and asthma control (ACQ6) were recorded. Results Thirty-seven patients (mean age 41, 70% female) were included in the analysis. The mean (SD) AER fell by almost 90% from 3.16(1.28) at dupilumab initiation to 0.35(0.72) after 1 year. The median (IQR) mOCS dose (n=20) fell from 10(5-25) mg to 0 (0-5) mg at 1 year, with 14/20 (70%) able to stop prednisolone altogether. Clinical remission was achieved in 16/37 (43%). Patients who achieved remission had a higher pre-IL5/5R FeNO level (85ppb [39-198] vs 75ppb [42-96], p=0.03). Conclusion Significant improvements in clinical outcomes are possible following a switch to dupilumab in patients experiencing a suboptimal response to anti-IL5/5R therapies. A higher FeNO in poor responders to anti-IL5/5R who achieve remission with dupilumab is suggestive of an IL-13 driven sub-phenotype of T2-high asthma in which the eosinophil appears unlikely to play a key role in the disease pathogenesis.