Total IgE as a biomarker of omalizumab response in chronic spontaneous urticaria: A meta-analysis

Background: Omalizumab is approved for the treatment of chronic spontaneous urticaria (CSU) that is refractory to antihistamines. Total immunoglobulin E (IgE) levels have emerged as a possible biomarker to predict response to omalizumab. However, the existing literature is heterogenous, with conflicting conclusions with regard to the role of total IgE levels. Objective: We sought to clarify the role of evaluating total IgE levels in patients with CSU by performing a meta-analysis on the existing literature to determine if meaningful changes exist between responders and nonresponders to omalizumab. Methods: A total of 68 unique citations were returned and screened by two independent reviewers. Editorials, reviews, and case reports were excluded, and a total of 33 original articles were identified and underwent secondary evaluation. Studies that present mean ± standard deviation total IgE levels and/or 95% confidence intervals (CI) were included, whereas studies with < 25 subjects were excluded. Three studies ultimately met these criteria. Results: We found a mean difference in total IgE levels between those who responded to omalizumab versus those without a response of 49.76 (95% CI, 7.13-92.38; p = 0.02), which demonstrated higher mean IgE values in responders compared with nonresponders. Conclusion: This study presents additional evidence that supports evaluation of total IgE levels as it pertains to response to omalizumab therapy in CSU. When considering the current evidence, it seems reasonable to consider the baseline total IgE level as a biomarker to predict the treatment response to omalizumab. Based on the existing literature, we cannot conclude at what threshold nonresponse is more likely to occur.