Clinical outcomes after switching from mepolizumab to benralizumab in eosinophilic granulomatosis with polyangiitis: A single-centre retrospective cohort study

OBJECTIVES: To investigate the impact of switching to benralizumab on flare risk in patients with eosinophilic granulomatosis with polyangiitis (EGPA) previously treated with mepolizumab. METHODS: We conducted a single-centre retrospective cohort study including 26 patients with EGPA who received mepolizumab. A landmark analysis was performed at 910 days after mepolizumab initiation (median time to switching), and patients were grouped according to treatment. The primary outcome was disease flares requiring treatment intensification. We used a Cox model with treatment switching as a time-dependent covariate. RESULTS: In the landmark analysis, the benralizumab group (n=4) had a higher flare rate than the mepolizumab group (n=10) (log-rank test, P = 0.002). However, the Cox model did not converge and the time-dependent analysis yielded an imprecise estimate (hazard ratio 3.14, 95% confidence interval 0.31-32.02). The 1-year flare-free rate after switching to benralizumab (n=19) was 94.1%, and no severe flares occurred. Most patients had low disease activity at switching, and switching was primarily driven by patient preference. CONCLUSIONS: Short-term flare-free survival after switching to benralizumab was high despite a small number of minor flares. Further evidence is warranted to assess long-term outcomes.