Biomarkers predicting the controller dose of omalizumab in patients with chronic spontaneous urticaria

Background Clinical trials showed the efficacy of 300 mg/4 weeks of omalizumab (OMA) during 6 months in patients with severe chronic spontaneous urticaria (CSU). Nevertheless, in real life, many patients require higher doses and/or longer treatment. This study assesses the real‐life performance of OMA in severe CSU and identifies factors associated with the response. Methods CSU patients eligible for OMA were recruited prospectively. Clinical data and a blood test were collected before OMA initiation. Urticaria Activity Score 7 (UAS7) was calculated at baseline and every 3 months during OMA treatment. CSU control was defined as UAS7 300 mg/4 weeks. A blood basophil count >20 cells/μL (OR 13.33; 95% CI 3.32–52.63; p 29 months at the end of the study (active responders, AR). AR had received OMA for a median of 45 months (30–100 months). There were no significant differences in clinical or analytical factors between RR and AR patients. Conclusions Low blood basophil count and the presence of hypothyroidism might serve as biomarkers for the controller dose of OMA in severe CSU patients. We recruited prospectively 89 adult patients with severe chronic spontaneous urticaria eligible for omalizumab, and collected clinical and analytical data in order to investigate biomarkers predictive of the controller dose and the treatment duration. Omalizumab controlled 94.4% of patients, but 17.9% of them required doses >300 mg/4 weeks. A blood basophil count >20 cells/μL and a normal thyroid function identified patients responsive to 300 mg/4 weeks. The median treatment duration in responders in remission (14.29% of patients) was 29 months, whereas active responders (38.1% of patients) had been on omalizumab for a median of 45 months at the end of the study. We did not find any predict