Comparison of omalizumab and mepolizumab treatment efficacy in patients with atopic and eosinophilic “Overlap” severe asthma: Biological agent preference in atopic-eosinophilic severe asthma

Approximately 1-third of patients with severe asthma are candidates for both omalizumab and mepolizumab treatment. We aimed to compare the clinical, spirometric and inflammatory efficacy of these 2 biologics in atopic and eosinophilic “overlap” severe asthma patients. In our 3-center retrospective cross-sectional observational study, the data of patients who received omalizumab or mepolizumab for at least 16 weeks to treat severe asthma were examined. Atopic (perennial allergen sensitivity and total IgE level 30–1500 IU/mL) and eosinophilic (blood eosinophil counts ≥150 cells/µL in admission; or ≥300 cells/µL in the previous year) patients with asthma suitable for both biologics were included in the study. Post-treatment changes in the asthma control test (ACT) score, number of attacks, forced expiratory volume in 1 second (FEV1), and eosinophil count were compared. The rates of any biological responder patient were compared according to whether they had high eosinophil counts (≥500 cells/µL vs <500 cells/µL). Total of 181 patients data were evaluated, of the 74 atopic and eosinophilic overlap patients included in the study, 56 were receiving omalizumab and 18 were receiving mepolizumab. When omalizumab and mepolizumab treatment efficacies were compared, there was no difference in terms of the reduction in attacks and improvement in ACT. The decrease in eosinophil levels in patients in the mepolizumab arm was significantly higher than that in patients in the omalizumab arm (46.3% vs 87.8%; P < .001). The improvement in FEV1 was greater with mepolizumab treatment, although the difference was not significant (215 mL vs 380 mL; P = .053). It has been shown that having high eosinophil counts does not affect the clinical and spirometric responder patient rates for either biological condition. The success of omalizumab and mepolizumab treatment is similar in patients with atopic and eosinophilic overlap with severe asthma. However, because the baseline patient inclusion criteria are not compatible, head-to-head studies comparing both biological agents are required.