Efficacy and Safety of Add-On Omalizumab in 4-6-Year-Old Children with Uncontrolled Allergic Asthma: A 52-Week Retrospective Study

Background: Allergic asthma is a common chronic inflammatory disease and the most prevalent asthma phenotype in children. Up to 80% of childhood asthma cases may have an allergic component. Preschool children aged 4–6 years represent a particularly vulnerable group due to ongoing immune and airway development. Although inhaled corticosteroids (ICS) are first‑line therapy, a subset of children remains inadequately controlled. Objective: The purpose of this study is to evaluate the efficacy and safety of omalizumab as an add-on therapy in children aged 4-6 years with allergic asthma who have suboptimal control with ICS. Methods: This is a single center, retrospective, non-randomized study that included 77 children with allergic asthma. Among them, 43 received add-on omalizumab (omalizumab group) combined with fluticasone propionate treatment, while 34 received fluticasone propionate alone (standard therapy group). Clinical analysis was conducted on asthma exacerbation rates, Childhood-Asthma Control Test (C-ACT) scores, fractional exhaled nitric oxide (FeNO), blood eosinophil percentage (EOS%), lung function parameters (FEV1% predicted (FEV1 % pred) and FEV1/FVC% predicted (FEV1/FVC % pred)), improvement of allergic comorbidities, and adverse events associated with omalizumab treatment at baseline, week 8, week 16, week 24, and week 52. Results: The omalizumab group demonstrated rapid and sustained clinical improvement. Compared to the standard therapy group, the omalizumab group showed a significant reduction in the rate of asthma exacerbations from week 8 to week 24 ( P < 0.01), a significant increase in the C-ACT scores ( P < 0.01) and a decrease in FeNO ( P < 0.01). Lung function parameters, including FEV 1 % pred and FEV 1 /FVC % pred, also showed improvement ( P < 0.05). By week 8 of omalizumab treatment, a marked reduction in eosinophil percentage (EOS%) was noted (P < 0.01). Longitudinal analysis of the omalizumab group confirmed that all efficacy indicators continued to improve through week 52. Meanwhile, treatment with omalizumab significantly improved symptoms associated with allergic rhinitis, conjunctivitis, atopic dermatitis, urticaria, and food allergies. This treatment regimen was well tolerated, with only one mild and transient injection site reaction reported in 541 subcutaneous administrations. Conclusion: In this retrospective study, add-on omalizumab was effective and safe in preschool children (4–6 years) with uncontrolled allergic asthma, improving symptom control, reducing exacerbations and type 2 inflammation, enhancing lung function, and alleviating allergic comorbidities.