Abstract: 【Abstract】 Objective To retrospectively analyze clinical efficacy and safety of omalizumab in the treatment of chronic urticaria （CU） in southern Zhejiang, China. Methods A retrospective observational study was conducted on CU patients who received omalizumab treatment at the First Affiliated Hospital of Wenzhou Medical University from January 1st, 2018 to August 1st, 2021. Through the outpatient follow-up visits, the disease activity, condition control, and quality of life were evaluated using the 7-day urticaria activity score （UAS7）, urticaria control test （UCT）, and dermatology life quality index （DLQI）. In addition, changes in disease condition, recurrence after withdrawal, and adverse events were assessed. Independent-sample t test was used for intergroup comparisons of normally distributed measurement data, Wilcoxon signed-rank sum test or Kruskal-Wallis H test was used for comparisons of non-normally distributed measurement data, and chi-square test or Fisher′s exact test was used for comparisons of enumeration data. Results A total of 252 CU patients with poor response to antihistamines were included, with a baseline UCT score of 5.0 ± 2.4 points, a UAS7 score of 25.6 ± 6.2 points, and a DLQI score of 17.5 ± 4.7 points; among them, 204 （81.0%） were treated with omalizumab at an initial dose of 300 mg, and 48 （19.0%） with omalizumab at an initial dose of 150 mg. At the end points （12.0 ± 1.4 months after the start of treatment）, an overall control rate of 90.3% （224/248） was achieved after the omalizumab treatment; concretely, 137 （55.2%） patients achieved complete control （UCT = 16 points）, 87 （35.1%） achieved partial control （12 points ≤ UCT < 16 points）, and 24 （9.7%） showed no response （UCT < 12 points）, while 10 with partial response shifted to complete control after dose increase. During the treatment period, recurrence occurred in 50 patients （36.5%）, of whom 32 patients opted for retreatment with omalizumab, and then 30 （93.8%） achieved partial or complete control. Adverse events were reported in 8 patients （3.2%）, and all were mild or moderate. Conclusion Omalizumab was effective in the real-world treatment of CU, and could improve patients′ quality of life, with a favorable safety profile.

Key words: Urticaria, Biological agents, Treatment outcome, Quality of life, Toxic actions, Chronic urticaria, Omalizumab