Comparison of the efficacy of different doses of omalizumab (150 mg vs 300 mg) in patients with seasonal allergic rhinitis and low total IgE: A randomized, double-blind, controlled study

Abstract Objective This study compares the efficacy of monthly subcutaneous injections of 150 mg versus 300 mg omalizumab in patients with seasonal allergic rhinitis (AR) caused by cypress pollen allergy and with total immunoglobulin E (IgE) levels below 100 IU/ml, aiming to provide a basis for individualized treatment in the population with low total IgE. Methods This single-center, randomized, double-blind, placebo-controlled trial enrolled 60 patients with seasonal allergic rhinitis induced by cypress pollen and total IgE levels below 100 IU/mL. Participants were randomly assigned (1:1) to receive a single subcutaneous injection of either 300 mg omalizumab or 150 mg omalizumab plus placebo within 5 days prior to the pollen season onset. The endpoints included daily symptom and medication scores (dSS, dMS, CSMS), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score, Allergic Rhinitis Control Test (ARCT) score, and nasal resistance. Results Among the 54 patients ultimately included in the analysis (27 in each group), the 300 mg group demonstrated significantly better outcomes than the 150 mg group in the CSMS (1.1 ± 0.1 vs 1.6 ± 0.1, P= 0.007), dSS (0.6 ± 0.1 vs 0.8 ± 0.1, P= 0.016), and ocular symptom score (0.5 ± 0.1 vs 0.7 ± 0.1, P= 0.003). The total RQLQ score in the 300 mg group was significantly lower than that in the 150 mg group during both the peak and late phases of the pollen season (P< 0.05). Furthermore, the ARCT score during the peak phase was significantly better in the 300 mg group (P= 0.011), and nasal resistance was significantly reduced (P= 0.020). No drug-related adverse reactions occurred in either group. Conclusions In patients with seasonal AR and total IgE levels of less than 100 IU/ml, a monthly dose of 300 mg omalizumab provided greater improvement in symptoms, quality of life, and nasal ventilation function compared with the 150 mg dose. This suggests that a higher individualized dosing strategy should be considered for such patients. Trial registration National Medical Research Registration and Filing Information System (MR-11-25-016855), registered 27 February 2025.