Re-Treatment with Omalizumab at One Year Interval for Japanese Cedar Pollen-Induced Seasonal Allergic Rhinitis Is Effective and Well Tolerated

Abstract

Background: Seasonal allergic rhinitis (SAR) induced by Japanese cedar pollens is a serious problem in Japan. Omalizumab, a humanized monoclonal anti-IgE antibody, improves symptoms associated with SAR, but a study comprehensively investigating the clinical efficacy, safety and pharmacological effects of omalizumab re-treatment has not yet been conducted. Methods: The open-label, 12-week study was carried out in 34 patients who had been treated with omalizumab in the core study conducted in the previous Japanese cedar pollen season. The study plan including study period, efficacy and safety endpoints, as well as dose regimen, was designed to be the same as in the core study. Omalizumab was administered subcutaneously every 2 or 4 weeks based on the serum IgE level and body weight of each patient. Results: Time course changes in daily nasal symptom medication scores as well as in daily ocular symptom medication scores throughout the pollen period were comparable with those in the omalizumab group in the core study. Serum free IgE levels decreased to below the target level in all patients and were equal to those in the omalizumab group in the core study. The adverse reaction profiles were similar to those in the core study. In addition, the overall incidence of drug-related adverse events and injection site reactions in the re-treatment study did not increase compared with those in the omalizumab group in the core study. There were no serious adverse events, and no anti-omalizumab antibodies were detected. Conclusion: Omalizumab was effective and safe when consecutively readministered in the second Japanese cedar pollen season.