Timing and duration of omalizumab response in patients with chronic idiopathic/spontaneous urticaria

BACKGROUND: Few data are available that describe response patterns in patients with chronic idiopathic urticaria (CIU)/chronic spontaneous urticaria (CSU) treated with omalizumab. OBJECTIVE: We sought to describe response patterns by using data from the 3 pivotal omalizumab CIU/CSU trials. METHODS: Every 4 weeks, randomized patients received dosing with placebo or 75, 150, or 300 mg of omalizumab (ASTERIA I: n = 318, 24 weeks; ASTERIA II: n = 322, 12 weeks) or placebo or 300 mg of omalizumab (GLACIAL: n = 335, 24 weeks). Response was defined as well-controlled urticaria (weekly Urticaria Activity Score UAS7 ≤ 6) or complete response (UAS7 = 0). RESULTS: Response rates were dose dependent and highest with 300 mg of omalizumab. Some patients responded early (before week 4). At week 12, a higher proportion of patients treated with 300 mg of omalizumab reported a UAS7 ≤ 6 (26.0% 75 mg of omalizumab, 40.0% 150 mg of omalizumab, 51.9% 300 mg of omalizumab, and 11.3% placebo for ASTERIA I; 26.8% 75 mg of omalizumab, 42.7% 150 mg of omalizumab, 65.8% 300 mg of omalizumab, and 19.0% placebo for ASTERIA II; and 52.4% 300 mg of omalizumab and 12.0% placebo for GLACIAL) or a UAS7 = 0 (11.7% 75 mg of omalizumab, 15.0% 150 mg of omalizumab, 35.8% 300 mg of omalizumab, and 8.8% placebo for ASTERIA I; 15.9% 75 mg of omalizumab, 22.0% 150 mg of omalizumab, 44.3% 300 mg of omalizumab, and 5.1% placebo for ASTERIA II; and 33.7% 300 mg of omalizumab and 4.8% placebo for GLACIAL). In patients receiving 300 mg of omalizumab with 24 weeks of treatment, median time to achieve a UAS7 ≤ 6 was 6 weeks (ASTERIA I and GLACIAL) and median time to achieve a UAS7 = 0 was 12 or 13 weeks (ASTERIA I and GLACIAL, respectively). Some patients who achieved well-controlled urticaria or complete response sustained response throughout the treatment period. CONCLUSION: Benefits of omalizumab treatment were evident early (before week 4) in some patients and persisted to week 24. Use of 300 mg of omalizumab demonstrated best results in controlling CIU/CSU symptoms.