Benralizumab and mepolizumab treatment outcomes in two severe asthma clinics

Background and Objective: This study compared the clinical outcomes of severe asthmatics treated with mepolizumab and benralizumab in a tertiary care severe asthma service setting. Methods: Patient data at baseline, six and 12 months were collected prospectively at two large tertiary hospital severe asthma clinics following treatment initiation. Two hundred and four patients received treatment with mepolizumab (117) or benralizumab (87). Baseline characteristics between groups were similar in regard to age, gender, body mass index, steroid dose and blood eosinophil count. However, the mepolizumab cohort had a higher Asthma Control Questionnaire Score (ACQ) at baseline (4.0 ± 1.1 vs. 3.6 ± 0.9, p = 0.018), accompanied by more frequent reliever medication usage and lower prebronchodilator FEV₁% (56.0 ± 20.1 vs. 63.8 ± 18.9, p = 0.008). Results: After 6 months treatment, both treatments induced significant improvements in (i) ACQ of 2.3 ± 0.1 (p < 0.001), (ii) oral steroid requiring exacerbations (incident rate ratio 0.26 (0.18–0.37), p < 0.001) and (iii) FEV₁. However, the improvement in FEV₁ was 0.18 (0.05–0.30) litres greater with benralizumab than with mepolizumab (p = 0.002) even when adjusting statistically for baseline differences between groups. These differences were even more pronounced at 12 months post-treatment initiation, when the improvement in exacerbation frequency with benralizumab was 64% greater than with mepolizumab (p = 0.01). Whilst both treatments significantly reduced the blood eosinophil count at 6 and 12 months, this reduction was substantially greater with benralizumab than mepolizumab (−260 cells/μL [−400 to −110, p = 0.001]). Conclusion: In this large group of severe eosinophilic asthmatics, mepolizumab and benralizumab both improved disease parameters. However, benralizumab treatment appeared significantly more effective than mepolizumab in reducing exacerbations, improving FEV₁ and depleting blood eosinophils.