Temporal, Drug Dose, and Sample Size Trends in the Efficacy of Omalizumab for Chronic Spontaneous Urticaria: A Cumulative Meta-Analysis

What is Known and Objective. Omalizumab is a humanized anti-IgE antibody, which is used in the treatment of chronic spontaneous urticaria (CSU). This study aims to investigate the trends in the efficacy of omalizumab for CSU, focusing on temporal aspects, drug dosages, and sample sizes. Methods. Cochrane, OVID MEDLINE, Embase, Web of Science, and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) from 1900 to January 2023. The primary outcome was the percentage of complete responders (defined as the weekly urticaria activity score as 0, UAS7 = 0). Secondary outcomes included the percentage of patients with UAS7 ≤ 6, the percentage of patients achieving a minimally necessary difference in weekly itch severity score (defined as a reduction from baseline in ISS7 of ≥5 points, ISS7 MID), and adverse events (AEs). A cumulative meta-analysis was performed with pooled risk ratio (RR) and 95% confidence intervals (CI). Publication bias was assessed by the contour-enhanced funnel plots with the trim-and-fill method, alongside Begg’s and Egger’s tests. Results and Discussion. Twelve randomized, placebo-controlled studies encompassing 2166 patients were analyzed. Compared with the placebo group, the omalizumab group exhibited significant increases in the proportion of patients achieving UAS7 = 0 [RR 5.18, 95% CI (3.97, 6.75), I² = 14%], UAS7 ≤ 6 [RR 3.21, 95% CI (2.69, 3.83), I² = 30%], and ISS7 MID responders [RR 1.50, 95% CI (1.39, 1.63), I² = 33%]. AEs were similar between the omalizumab group and placebo group [RR 0.96, 95% CI (0.89, 1.03), I² = 4%]. What is New and Conclusion. The cumulative meta-analysis confirmed that the efficacy outcomes for omalizumab have remained consistent over time, across different drug doses and sample sizes, with improved precision from newer studies. Omalizumab is confirmed to be safe and effective for CSU. It is also suggested to minimize redundant RCTs to conserve scientific and medical resources efficiently.