Sex differences in the efficacy of omalizumab in the treatment of chronic spontaneous urticaria

Background: Omalizumab is shown to be effective in the treatment of chronic spontaneous urticaria (CSU), a disease with high personal and social impact. Sex differences in CSU are recognized with women more frequently affected. Scarce is the knowledge about response to omalizumab between sex groups. We sought to identify any differences based on the sex of patients receiving omalizumab. Methods: We evaluated data of patients diagnosed with CSU refractory to high-dose second-generation H1 antihistamines and treated with 300 mg omalizumab every 4 weeks for 6 months and then at relapse. Results: Discussion: All patients, regardless of sex, age, or any other factor, achieved the clinical remission of the disease after the first 3 doses with a reduction of the disease activity indices and impact on the quality of life. Recurrences predominate in men, two months after the suspension of the drug. Respect to sex and recurrence we did not find any correlation with age, body mass index, peripheral eosinophil counts, total IgE levels, D-dimer, plasma prothrombine level or C-reactive protein. We found no sex differences in tolerability and safety. CSU in girls may persist longer and have worse prognosis, but no one has so far noted sex differences in response to omalizumab. Conclusions: Although there are no certainties on the mechanism of action of omalizumab in CSU, the noticeable difference in response between males and females lead us to suppose a role of the hormonal balance both on the pathogenesis of the CSU and on the efficacy of OmAb.