[Preliminary clinical observation of omalizumab therapy for moderate to severe asthma]

Objective: To observe the effectiveness, safety and management of omalizumab therapy for moderate to severe asthma in real-world clinical practice in China. Methods: This retrospective analysis involved 79 patients with moderate to severe asthma who received omalizumab therapy for at least 4 months in the First Affiliated Hospital of Guangzhou Medical University from March 2018 to April 2020. All participants were between 14 to 76 years old(median 50 years),including 30 males and 49 females. Data regarding the patients' clinical manifestations, eosinophil count, fractional exhaled nitric oxide (FeNO), lung function, oral corticosteroid dosage, and adverse reactions were collected before and after treatment. Paired t-test or non-parametric paired Wilcoxon analysis was used for pairwise comparison, Mann Whitney analysis for inter-group comparison, and Chi square test or Fisher test for inter-group comparison of count data. Results: The following changes were noted after 4 months of omalizumab thearpy. The patients' Asthma Control Test (ACT) scores increased from 17.0 (13.0-19.0) to 20.0 (18.0-24.0) points (P<0.001). The frequency of acute exacerbations(AE) decreased from 1.0 (0-1.0) to 0 (0-1.0) episodes every 4 months (P<0.001). The variation rate of the peak expiratory flow (PEF) decreased from 16.5 (13.8-27.3)% to 10.4 (6.0-16.2)% (P<0.001). The percent predicted value of PEF (PEFpred%) increased from 71.7 (51.4-91.6)% to 87.5 (65.2-105.5)% (P<0.001). The percent predicted value of the forced expiratory volume in 1 second(FEV₁%pred) increased from 73.6 (53.9-90.8)% to 80.6 (68.7-91.8)% (P=0.007). The maintenance dose of oral corticosteroids (OCS) decreased from 12.0 (10.0-20.0) to 5.0 (0-17.5) mg/day (P=0.001). After 4 months of treatment, the response rate of the 79 patients with asthma was 74.7%. The response rate of patients with allergic asthma (77.3%) was higher than that of patients with non-allergic asthma (25.0%) (P=0.019). Among 5 patients who completed 1 year of treatment, the ACT score, frequency of AE, PEFpred%, variation rate of PEF and OCS maintenance dose were still improved after 1 year of treatment. Adverse reactions occurred in 3 patients (3.8%), for a total of 3 (0.6%) times. Stratified analysis showed that after 4 months of treatment, the improvement in the ACT score and the decrease in the PEF variation rate among patients who reached the recommended treatment dose (full dose) [3.0 (1.0-8.0) points, 6.5 (3.5-15.8) %] were significantly higher than those among patients who did not reach the recommended treatment dose (insufficient dose) [1.0 (-0.3-3.0) points, 2.9 (1.5-5.0) %] (P<0.05). Additionally, the treatment response rate in patients with a sufficient dose (80.0%) was higher than that in patients with an insufficient dose (50.0%) (P=0.019).The main factors associated with stopping treatment within 1 year despite a response to omalizumab was economic burden (70.3%), followed by satisfactory improvement by self-evaluation (21.9%) and less improvement in symptoms than expected (7.8%). Conclusion: Omalizumab was an effective treatment for moderate to severe allergic asthma with few adverse effects. The response rate was higher when the recommended injection dose was achieved. Financial difficulty was the main reason for stopping treatment within 1 year despite a good therapeutic response.