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.

The potential role of omalizumab in the treatment of chronic urticaria.

Treatment of chronic urticaria refractory to antihistamines presents a challenge to both people affected with the disease as well as the physicians who treat them. Omalizumab, a monoclonal antibody against IgE, has emerged as one potential solution to this challenge. In several clinical trials published between 2011 and 2013, omalizumab significantly reduced or eliminated symptoms of chronic urticaria. The optimal dose for chronic urticaria is 300 mg administered every 4 weeks, a dose that differs from those used in asthma, which are based on the patient's weight and IgE level. Omalizumab does not appear to cause lasting symptom remission, and the ideal duration of treatment for chronic urticaria has not been defined.

Urticaria and autoimmunity: where are we now?

There is considerable debate whether chronic urticaria is an autoimmune disease or whether its features suggestive of autoimmunity are epiphenomena. A plethora of circumstantial evidence suggests that chronic urticaria is an autoimmune disease, but criteria to establish autoimmunity require direct proof and indirect evidence, and these are lacking in chronic urticaria. Current approaches to assessing for autoimmunity in vivo via the autologous serum skin test, and in vitro via either basophil histamine release or the basophil activation test are widely utilized, but the results of these tests have limited impact on prediction of the clinical course and efficacy of treatments. Recent guidelines for diagnosing autoimmune urticaria have been proposed, but further investigation is needed.