Evaluating the Efficacy of Omalizumab in Severe Cedar Seasonal Allergic Rhinitis in Japan

Traditional treatments for cedar seasonal allergic rhinitis include second-generation antihistamines, nasal corticosteroids, and sublingual immunotherapy (SLIT). Omalizumab (Xolair®), an anti-immunoglobulin E (IgE) monoclonal antibody, is an additional option for severe cases unresponsive to existing therapies. Numerous studies have demonstrated the therapeutic effectiveness of omalizumab for cedar seasonal allergic rhinitis; however, most reported results after only up to four weeks of follow-up. Therefore, this study evaluates the clinical efficacy of omalizumab throughout one whole cedar pollen season. Subjects and methods: This study included patients from our department and the Otorhinolaryngology Department of Minami Osaka Hospital between 2021 and 2023 who were ≥ 12 years old and had serum total IgE levels of 30-1,500 IU/mL, a baseline weight of 30-150 kg, and persistent severe nasal symptoms despite conventional treatments. Patients taking oral steroids at the time of enrollment or had fewer than two omalizumab doses were excluded. Forty-six patients (26 males, 20 females; mean age, 19.1 ± 11.2 years) met these criteria and received subcutaneous omalizumab every 2 or 4 weeks based on their IgE levels and weight. Symptoms were assessed at baseline and 4, 8, and 12 weeks post-administration using the Total Nasal Symptom Score (TNSS) and the Japanese Standard Quality of Life Questionnaire (JRQLQ No. 1) for allergic rhinitis. Results: Thirty-six patients were followed up for 8 weeks and 13 for 12 weeks. TNSS significantly improved from 6.6 to 4.5 at 4 weeks, 4.2 at 8 weeks, and 4.1 at 12 weeks (p