Effect of omalizumab on angioedema in H1‐antihistamine‐resistant chronic spontaneous urticaria patients: results from X‐ACT, a randomized controlled trial

Abstract Background Chronic spontaneous urticaria ( CSU ) severely impacts quality of life (QoL), especially in patients with wheals and angioedema. Omalizumab is approved as add‐on therapy for CSU patients; however, its effect on patients who are double‐positive for wheals and angioedema has not been systematically studied. Objective The primary objective was to evaluate the efficacy of omalizumab vs placebo at week 28 using the Chronic Urticaria Quality of Life ( CU ‐Q2oL) questionnaire. Number of angioedema‐burdened days, time interval between successive angioedema episodes, disease activity, angioedema‐specific and overall QoL impairment were secondary objectives. Methods X‐ ACT was a phase III , randomized, double‐blind study conducted in 24 centres (Germany), which selectively included CSU patients with angioedema and wheals. Patients were randomized (1 : 1) to omalizumab 300 mg or placebo (every 4 weeks up to week 24) (ClinicalTrials.gov number: NCT 01723072). Results Of the 91 patients randomized to omalizumab ( n = 44) or placebo ( n = 47) at baseline, 68 completed the 28‐week treatment phase (omalizumab, 35; placebo, 33). Omalizumab was superior to placebo in improving CU ‐Q2oL scores at week 28 ( P < 0.001). There was a threefold improvement in angioedema‐burdened days/week with omalizumab (0.3) vs placebo (1.1). The median time to first recurrence of angioedema was 57–63 days with omalizumab and <5 days with placebo. Omalizumab significantly improved angioedema‐specific QoL ( P < 0.001). The adverse events reported are in line with the established safety profile of omalizumab. Conclusion Omalizumab was an effective treatment option for patients with moderate‐to‐severe CSU symptoms and angioedema unresponsive to high doses of antihistamine treatment.