Biologic Switching in Patients with Severe Asthma: Effects on Exacerbations, Corticosteroid Use and Lung Function

Background/Objectives: This study aimed to evaluate the clinical outcomes of biologic switching in patients with severe asthma in real-world settings. Methods: In this retrospective study, asthma exacerbations, systemic corticosteroid use, asthma control, and spirometric parameters were compared before and one year after biologic switching in adults with severe asthma. All patients were analyzed as a single cohort, with additional subgroup analyses performed according to the type of biologic switch (omalizumab to mepolizumab, mepolizumab to benralizumab, and omalizumab to benralizumab). Results: Among 29 patients who underwent biologic switching, the median annual exacerbation rate decreased from 2.0 (IQR, 1.5-2.5) to 0 (IQR, 0-1) at one year (p < 0.001), while systemic corticosteroid use declined from 69.0% (n = 20) to 34.5% (n = 10) (p = 0.002). A total of 38.0% of patients (n = 11) were switched from mepolizumab to benralizumab, 58.6% (n = 17) from omalizumab to mepolizumab, and 3.4% (n = 1) from omalizumab to benralizumab. In patients switched from omalizumab to mepolizumab, significant reductions were observed in annual exacerbations and in both the rate and dose of systemic corticosteroid use, along with improved asthma control (p = 0.002, p = 0.008, p = 0.002, and p = 0.001, respectively). In contrast, among patients switched from mepolizumab to benralizumab, exacerbation rates decreased significantly (p = 0.019), with no significant changes in systemic corticosteroid use (p = 1.000) or dose (p = 0.102). Only one patient was switched from omalizumab to benralizumab and showed improvements in exacerbation frequency, asthma control, systemic corticosteroid use, and spirometric parameters. The mean age of the patients was 53.24 ± 10.74 years (range, 33-73), with 51.7% being female (n = 15). Conclusions: Biologic switching was associated with favorable clinical outcomes, including fewer exacerbations and improved asthma control, in selected patients with severe asthma who showed an inadequate response to their current biologic therapy.