Omalizumab therapy for treatment of recalcitrant chronic spontaneous urticaria in an Asian population

Objectives: There are limited data regarding omalizumab in the treatment of recalcitrant chronic spontaneous urticaria (CSU) in Asian populations. This study evaluated the effectiveness and the proper dosage of omalizumab for Asian CSU patients in a real-life setting. Methods: We retrospectively reviewed recalcitrant CSU patients seeking treatment at the Skin Allergy Clinic, Siriraj Hospital during the 3-year period. All patients were treated with omalizumab as an add-on therapy. Standard seven-day urticaria activity score (UAS7) and medication score were used to assess omalizumab response. Results: Of 13 patients, 9 patients (70%) responded well to 150mg omalizumab injection every month, whereas 4 patients requiring updosing to 300mg. In the 150mg group, one patient achieved complete symptom control without antihistamine intake. Most of them required antihistamines without prednisolone and ciclosporin. Onset of omalizumab was fast, usually within the first week. Though only two patients in the 300mg group achieved complete absence of symptoms, ciclosporin and oral corticosteroids could be discontinued. No patients reported adverse effects. Conclusions: Omalizumab at an initial dosage of 150mg was effective in the treatment of recalcitrant CSU among Asians. Updosing to 300mg was required to achieve satisfactory outcomes.