**8. Omalizumab treatment for special populations**

Although ASTERIA II [10] and GLACIAL [11] did include patients with 12 years and older, none of these larger trials addressed the use of omalizumab in the pediatric population below this age. Although significantly less common in the pediatric population, CU affects 0.1% to 0.3% of children with a similar morbidity profile as the adult population. A case series of the use of omalizumab for CU in the 4 patients in age from 4 to 16 years found that all 4 patients obtained complete response to omalizumab 150 mg monthly for the younger ones (age 4 and 5 years) and 300 mg monthly for the older patients at 10 and 16 years without any reported adverse events [45].

The EXPECT study evaluated the use of omalizumab during pregnancy [46]. In total, 191 pregnant women were included who had moderate to severe asthma and received at least 1 dose of omalizumab 8 weeks before conception or at any time during pregnancy. Based on the known outcomes of 169 pregnancies, there was no significant difference in spontaneous abortion, major congenital anomalies, prematurity, or low birth weight compared with a similar asthma population reported in previous studies [47, 48]. Because of the small number of patients in the study, it is difficult to draw any conclusions of safety on the use of omalizumab during pregnancy for CU [28]. Further studies are needed with larger sample sizes.

### **9. Safety issues of omalizumab**

Safety was closely evaluated in all the randomized phase III trials [9–11]. ASTERIA II reported more headaches in the omalizumab 150 mg group compared with placebo but otherwise had no significant differences in adverse events. The GLACIAL study [11] showed no significant difference in adverse events between omalizumab group and placebo but did have some system-specific differences. In ASTERIA I, [9] headaches, arthralgia, and injection-site reactions were more common in the omalizumab groups but there was no significant difference in serious adverse events. No deaths, malignancies, or anaphylactic episodes were reported in these trials due to omalizumab.

*The Use of Omalizumab in Chronic Urticaria: Available Data and Future Aspects of Anti-IgE… DOI: http://dx.doi.org/10.5772/intechopen.97226*

Overall, omalizumab is very well tolerated and adverse reactions occurred in patients taking omalizumab were compatible with those on placebo in prospective, randomized trials for CU [3, 20, 49–51]. The most seriously considered adverse reaction is anaphylaxis-related to omalizumab that is defined as a combination of angioedema of the throat or tongue, bronchospasm, hypotension, syncope, and/or urticaria [52]. Omalizumab joint task force reviewed clinical trials and postmarketing surveillance data on omalizumab-induced anaphylaxis or anaphylactoid reactions [53]. They found a total of 35 patients with 42 episodes of anaphylaxis-related to omalizumab injection. Considering a total of 39510 patients who had exposed once to omalizumab, they estimated an anaphylaxis-reporting rate of 0.09% of patients [53]. The risk of anaphylaxis in patients with CU appears to be less than in those treated for asthma. In addition, there does not seem to be a dose-related effect on adverse events.
