Influence of Omalizumab Therapy on Airway Remodeling Assessed with High-Resolution Computed Tomography (HRCT) in Severe Allergic Asthma Patients

Introduction: Airway remodeling is an important factor in persistent obstruction in severe asthma. High resolution computed tomography (HRCT) is an effective method of detecting changes in airway structure. Our aim was to use HRCT to assess changes in airway remodeling in patients with severe allergic asthma who are treated with omalizumab. Material and methods: In 12 patients with severe allergic asthma, HRCT was performed before and after treatment with omalizumab. In selected bronchial airways, parameters were calculated: bronchial wall area (BA), also corrected for body surface area (BSA); percentage of wall area (WA%); and the ratio of luminal area to total bronchial area (Ai/Ao). Clinical response to treatment was assessed using an asthma control questionnaire (ACQ), asthma quality of life questionnaire (AQLQ), and number of exacerbations per year. Assessment included spirometry and blood eosinophilia. Results: Treatment resulted in significant improvement in ACQ (p = 0.035) and AQLQ (p = 0.001). We observed significant reduction in exacerbations per year (p = 0.002) and reduction of daily systemic steroid dose (p = 0.032). FEV₁ and peripheral blood eospinophilia did not change (p = 0.846 and p = 0.221). Airway dimensions (Ai/Ao) of particular bronchi were consistent with the mean of the parameters calculated for all bronchi measured. Although we observed a significant decrease in WA (p = 0.002) and WA/BSA (p = 0.002), WA% and Ai/Ao did not improve (p = 0.39 and p = 0.49). We found no correlations between changes in airways and changes in spirometry or clinical parameters. Conclusion: Despite clinical effectiveness of omalizumab, its effect on airway remodeling may be limited.