The effect of biologics on pulmonary function tests and small airways in patients with severe asthma: a real-life study.

INTRODUCTION: Significant advances have been made in the treatment and management of severe asthma with the development of biological treatments. OBJECTIVE: The aim of this study was to investigate changes in lung function tests potentially reflecting distal airflow limitation in patients with T2-high severe asthma treated with biological agents. METHODS: The study included a total of 80 patients diagnosed with T2-high severe asthma who were treated with biologics (omalizumab (n = 36 (45%)), mepolizumab (n = 35 (43.8%)), or benralizumab (n = 9 (11.2%)) for at least 1 year. The demographic data, comorbid diseases, asthma control test (ACT) scores, exacerbation rates, and pulmonary function test results of the patients were evaluated retrospectively. RESULTS: The rate of male patients was higher in the benralizumab group (p = 0.017), allergic rhinitis and atopy were significantly higher in the omalizumab group (p < 0.001), and CRSwNP was higher in the mepolizumab and benralizumab groups compared to the omalizumab group (p < 0.001). At 12 months after treatment with omalizumab and mepolizumab, all pulmonary function tests (FEV1, FVC, FEV1/FVC, FEF25, FEF50, FEF75, FEF25-75, PEF) showed a statistically significant increase, ACT score increased, blood eosinophil count decreased, and the number of annual asthma exacerbations decreased (p < 0.05). At 12 months after treatment with benralizumab, the increase in FEF50 and FEV1/FVC and the decrease in the number of annual asthma exacerbations were statistically significant (p < 0.05). CONCLUSION: In conclusion, the findings of this study support that biologics were associated with improvements in spirometric parameters potentially reflecting distal airflow limitation.