Background: Following the results of the MANDARA trial, this real-life study aimed at comparing the effectiveness and safety profile of mepolizumab versus benralizumab in a European EGPA cohort. Methods: We conducted a retrospective observational comparative study including EGPA patients, who received mepolizumab or benralizumab at the asthma dose. Patients were matched 1:1 by sex, age, BVAS and oral corticosteroid (OCS) dosage at the treatment initiation (T0). Complete response (CR) and partial response (PR), disease activity, OCS, pulmonary parameters, eosinophil count, relapses, and safety outcomes were also compared at 3, 6 and 12 months. Results: Patients treated with mepolizumab or benralizumab (n=88 each) were matched: 57% were females, median age was 54 years (IQR 45-60), median OCS dose 10 (7.5-12.5) and 10 (7-13) mg/day, median BVAS 4 (2-7) and 3 (2-8), respectively. 45.4% of patients in the mepolizumab group and 51.1% in the benralizumab group achieved CR or PR at T3, with CR steadily increasing during follow-up for both treatments. At T12, a higher CR rate was found in the benralizumab group (48.1% vs 32.4%, p=0.005). No differences in BVAS, OCS, and respiratory parameters were observed between groups at the different timepoints. Throughout the follow-up, both treatments reduced eosinophil count, although a deeper reduction was found in the benralizumab group at all timepoints (p<0.0001). Safety profile was comparable between patient groups. Conclusion: Mepolizumab and benralizumab showed comparable overall effectiveness and safety in EGPA. However, benralizumab achieved a higher CR rate at T12, and a deeper peripheral eosinophil reduction.

Objectives. We compared the common pathway components C3a, C5a and membrane attack complex (MAC), also known as C5b-9, and the alternative pathway components factor B and properdin in patients with ANCA-associated vasculitis (AAV) and healthy controls, and conducted a meta-analysis of the available clinical evidence for the role of complement activation in the pathogenesis of AAV. Methods. Complement components were evaluated in 59 patients with newly diagnosed or relapsing granulomatosis with polyangiitis or microscopic polyangiitis and 36 healthy volunteers. In 28 patients, testing was repeated in remission. Next, we performed a meta-analysis by searching databases to identify studies comparing complement levels in AAV patients and controls. A random-effects model was used for statistical analyses. Results. The median concentrations of MAC, C5a, C3a, and factor B were higher in active AAV patients (p<0.001). Achievement of remission was associated with reductions in C3a (p=0.005), C5a (p=0.035), and factor B levels (p=0.045), whereas MAC and properdin levels did not change. In active AAV, there were no effects of ANCA specificity, disease phenotype, previous immunosuppression, or disease severity on complement levels. A total of 1122 articles were screened, and five studies, including this report, were entered in the meta-analysis. Plasma MAC, C5a, and factor B in patients with active AAV were increased compared to patients in remission (excluding factor B) and controls. Changes in C3a were of borderline significance. Conclusion. Our findings and the results of the meta-analysis support activation of the complement system predominantly via the alternative pathway in AAV patients.