Abstract
PURPOSE: Omalizumab, the anti-IgE monoclonal antibody used to treat severe asthma, reduces asthma exacerbations, hospitalizations, and corticosteroid use. Although allergic asthma is a therapeutic target of omalizumab, omalizumab is not effective in all patients with severe allergic asthma and is not always available for long-term use. We retrospectively investigated factors related to long-term (≥2 years) use of omalizumab for severe asthma. PATIENTS AND METHODS: Of the 116 patients treated with omalizumab for severe asthma at our hospital between 2009 and 2017, 82 were included in this retrospective analysis. Thirty-four were excluded because of adverse events, financial difficulties, or hospital transfers. The number of asthma exacerbations, unscheduled visits, corticosteroid doses, asthma control test scores, pulmonary function test results, and fractional exhaled nitric oxide levels were evaluated. RESULTS: The median age of the study population was 58 years, with 66% female and 26% taking regular oral corticosteroids. After 2 years of treatment, 52 responders were identified using the global evaluation of treatment effectiveness (GETE) score. Improvements in asthma control test scores, airflow limitation, exacerbations, and oral corticosteroid use were observed in the responders. Multivariate analysis revealed that a peripheral blood eosinophil count of ≥200 or a perennial antigen-specific IgE antibody positivity of ≥2 predicted a response at the 2-year mark. However, Kaplan-Meier analysis demonstrated that neither high eosinophil counts nor perennial antigen-specific IgE positivity influenced the prolongation of treatment beyond 2 years, and responders at 2 years underwent omalizumab treatment for a significantly longer period than non-responders (HR = 9.89, p < 0.001), with GETE at 2 years being the only predictor of long-term omalizumab use. CONCLUSION: In this retrospective study the GETE after 2 years of omalizumab therapy emerged as the most meaningful predictor of the long-term effectiveness of omalizumab treatment in patients with severe asthma, highlighting the benefits of prolonged therapy in certain populations. These findings may guide future therapeutic strategies for severe asthma.