ATLANTA, GA—At the 2017 AAAAI Annual Meeting, study authors presented that a “higher-than-expected number of patients responded to omalizumab” during the 24-week open-label and were eligible for randomization in the subsequent double-blind period. 

Thomas B. Casale, MD, FAAAAI, from the University of South Florida, Tampa, FL, and coauthors summarized the XTEND-CIU study design, baseline characteristics, and outcomes for the 24-week open-label period. The XTEND-CIU study assessed patients aged ≥12 years for the safety and efficacy of longer-term omalizumab treatment (48 weeks) and helped to better understand drug discontinuation in patients with chronic idiopathic urticaria. 

Study patients who remained symptomatic despite standard H1 antihistamine treatment, H2 blockers, and/or leukotriene receptor modifiers were enrolled. The study consisted of 4 phases: a 14-day screening, a 24-week open-label, 24-week randomized double-blind (omalizumab or placebo), and a follow-up period (Weeks 48–60).

For study enrollment, patients were required to have 7-day urticaria activity score (UAS7) ≥16 within 7 days before baseline. For randomization, patients were required to have UAS7 ≤6 in the final 2 weeks of the open-label period. Patients were given omalizumab 300mg subcutaneously every 4 weeks. “Based on the data from the pivotal trials, 57% of patients were expected to be randomized,” noted Dr. Casale. 

Of the 206 total enrolled patients, 85% (n=175) completed the open-label period and 65% (n=134) were randomized. At baseline, mean (standard deviation [SD]) scores were: UAS7 score 32.2 (7.0), weekly itch score 15.4 (3.6), and weekly number of angioedema days 2.2 (2.7). By the end of the open-label period, there was a decrease in the average UAS7 and weekly itch scores to 6.2 (11.0) and 2.4 (4.7), respectively. 

Dr. Casale added, “No new safety signals were detected.”