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.