Real-World Effectiveness of Omalizumab Treatment in Adult Asthma Patients

Abstract

Purpose: Omalizumab improves clinical outcomes for patients with severe asthma (SA), but its long-term effectiveness and potential biomarkers for predicting patient response require further investigation. This study aimed to evaluate the real-world effectiveness of omalizumab in treating SA and to identify potential biomarkers for predicting a favorable treatment response.

Materials and methods: Clinical outcomes were compared between asthma patients receiving omalizumab (omalizumab group) and those on inhaled corticosteroid with long-acting beta-agonist (ICS-LABA) alone (ICS-LABA group). Propensity score matching and Cox proportional hazards model were used to calculate hazard ratios (HRs). Study outcomes included severe asthma exacerbation (SAE), incompletely controlled asthma, intravenous (IV) corticosteroid use, and asthma-related hospitalization. Incompletely controlled asthma was defined by blood eosinophil counts ≥150 cells/µL, fractional exhaled nitric oxide (FeNO) ≥25 ppb, forced expiratory volume in one second (FEV1%) <80%, or SAE occurrence.

Results: The omalizumab group had significantly lower risks of SAE (HR 0.17, p=0.03), incompletely controlled asthma (HR 0.56, p=0.04), IV corticosteroid treatment (HR 0.38, p=0.02), and asthma-related hospitalization (HR 0.27, p=0.05). Blood eosinophil count stayed lower in the omalizumab group. FEV1% was higher with the omalizumab group, while blood neutrophil count, FeNO, and serum total IgE showed no differences. Furthermore, subgroup analysis showed patients with treatment-favorable response (>50% reduction in systemic corticosteroid dose) exhibited decreased blood neutrophil counts but increased FEV1% and serum total IgE levels compared with the treatment-unfavorable group.

Conclusion: Omalizumab treatment effectively reduces SAE and improves lung function and asthma control. Blood neutrophil counts and serum total IgE may be potential biomarkers for predicting favorable responses to omalizumab treatment.

Keywords: Asthma; IgE; neutrophils; omalizumab.

Fig. 1. Definitions of the omalizumab and ICS-LABA groups. (A) Adults with severe asthma from January 1994 to February 2023 who had consistently taken omalizumab. (B) Adult patients with severe asthma from January 1994 to February 2023 who had asthma for at least 1 year and had taken an ICS-LABA without type 2 biologics. ICS-LABA, inhaled corticosteroid with long-acting beta-agonist.

Fig. 2. Comparisons of the cumulative incidence of severe asthma exacerbations and other outcomes between the omalizumab and ICS-LABA groups. p values were derived from the log-rank test. ICS-LABA, inhaled corticosteroid with long-acting beta-agonist; IV, intravenous.

Fig. 3. Longitudinal changes in laboratory values during the follow-up period according to the linear mixed-effects model in the omalizumab (solid line with a closed circle) and ICS-LABA (dashed line with an open circle) groups. (A) Blood eosinophil counts (cells/µL). (B) Blood neutrophil counts (cells/µL). (C) Serum total IgE (IU/mL). (D) Fractional exhaled nitric oxide (ppb). (E) FEV1 measured/predicted (%). (F) Erythrocyte sedimentation rate. Error bars indicate a 95% confidence interval. ICS-LABA, inhaled corticosteroid with long-acting beta-agonist; FEV1, forced expiratory volume in one second.

Fig. 4. Forest plot of the sensitivity analyses for severe asthma exacerbations and other outcomes based on various analytic settings. ICS-LABA, inhaled corticosteroid with long-acting beta-agonist; IR, incidence rate; PY, person-year; IV, intravenous; CI, confidence interval.

Fig. 5. Longitudinal changes in laboratory values during the follow-up period according to the linear mixed-effects model in the treatment-favorable (solid line with a closed circle) and treatment-unfavorable (dashed line with an open circle) subgroups within the omalizumab group. (A) Blood neutrophil counts (cells/µL). (B) Blood eosinophil counts (cells/µL). (C) Serum total IgE (IU/mL). (D) Fractional exhaled nitric oxide (ppb). (E) FEV1 measured/predicted (%). (F) Blood leukocytes (×10³/µL). Error bars indicate the 95% confidence interval. ICS-LABA, inhaled corticosteroid with long-acting beta-agonist; FEV1, forced expiratory volume in one second.