Omalizumab for chronic urticaria in Latin America

Chronic urticaria (CU) is defined as the spontaneous appearance of wheals, with or without angioedema, persisting for ≥6 weeks. Chronic Spontaneous Urticaria (CSU) is a type of CU which affects 0.5-1 % of the global population, but it represents a high burden to patients. In recent years, omalizumab is available as treatment of disease. Our aim is to extend previous findings, analyzing effects of omalizumab on symptoms in Latin American patients with CSU.

Retrospective analysis of patients treated with omalizumab in Cuenca-Ecuador. 150 mg omalizumab was administered every 4 weeks, and its effects were measured by Urticaria Activity Score (UAS) at baseline and each month in follow up. Complete response was defined as a UAS of 0 or 1, and partial response was classified as a UAS of 2 or more. Also, demographic and clinical variables were collected. Descriptive analyses were employed. Response rates were summarized as counts and percentages after 3 and 5 months. Related Samples Wilcoxon signed rank tests were used to compare UAS at baseline and after 3 months. P values <0.05 indicated statistical significance.

26 subjects were enrolled, almost half were female individuals (57.7 %), with mean age 47.8 years (range, 18-81 years). Mean duration of CU after diagnosis was 23.3 months (range, 2-180 months). Mean UAS at baseline was 5.7 points (range, 4-6 points). Nine patients (34.6 %) completed 3 months of treatment (33 % reported a complete response), with a mean difference in UAS of 3.33 (p = 0.01). Four patients completed 5 months of treatment (75.0 % showed a complete response). All patients previously treated with first-generation antihistamines plus corticosteroids showed no responses at neither 3 nor 5 months of treatment.

Omalizumab is an effective treatment for patients with CU. It is necessary to conduct some future investigations where we can establish if 150 mg could be an option in developing countries.