Comprehensive efficacy of omalizumab for severe refractory asthma: a time-series observational study.

BACKGROUND: Omalizumab, a humanized anti-IgE monoclonal antibody, is reportedly an effective treatment for severe allergic asthma. However, there have been few comprehensive analyses of its efficacy, including assessments of small airways or airway remodeling. OBJECTIVE: To comprehensively evaluate the efficacy of omalizumab, including its effects on small airways and airway remodeling, in adult patients with severe refractory asthma. METHODS: In this prospective, time-series, single-arm observational study, 31 adult patients with severe refractory asthma despite the use of multiple controller medications, including high-dose inhaled corticosteroids (1,432 ± 581 µg/d of fluticasone propionate equivalent), were enrolled. Clinical variables, including Asthma Quality of Life Questionnaire, asthma exacerbations, exhaled nitric oxide, pulmonary function, methacholine airway responsiveness, induced sputum, and chest computed tomogram, were assessed at baseline and after 16 and 48 weeks of treatment with omalizumab. RESULTS: Twenty-six of the 31 patients completed 48 weeks of treatment. For these patients, Asthma Quality of Life Questionnaire scores and peak expiratory flow values significantly and continuously improved throughout the 48 weeks (P < .001 for all comparisons). Unscheduled physician visits, asthma exacerbations requiring systemic corticosteroids, fractional exhaled nitric oxide at 50 mL/s and alveolar nitric oxide levels, sputum eosinophil proportions, and airway-wall thickness as assessed by computed tomography significantly decreased at 48 weeks (P < .05 for all comparisons). CONCLUSION: Omalizumab was effective for adult patients with severe refractory asthma. Omalizumab may have anti-inflammatory effects on small airways and reverse airway remodeling. TRIAL REGISTRATION: UMIN000002389.