Three-month, Single-center Study to Identify Biomarkers/Response to Xolair Therapy in Chronic Idiopathic Urticaria

This is a single center, non-comparative exploratory study, to investigate the effect of omalizumab over a 3-month treatment period in adult (≥18 years) patients with chronic idiopathic urticaria who had remained symptomatic despite the use of high dose H1-antihistamines. After an initial screening visit within two weeks of the Day 1 baseline visit, patients receive one subcutaneous injection of omalizumab at a dose of 300 mg on Days 1, 30, and 60. Patients will return for clinical assessments and blood draws on Day 3 and Day 30 (study conclusion). Blood will be collected at the screening visit (Day -14), baseline (Day 1, prior to omalizumab injection), Day 14, Day 30 (prior to omalizumab injection), Day 60 (prior to omalizumab injection), and Day 90 (study completion) for microsomal miRNA extraction, basophil isolation, and also stored at -70oC for later periostin assays for a total of 275ml of blood over the course of the study (25ml at screening and 50ml for each of the 5 subsequent visits (i.e., Days 1, 14, 30, 60, and 90). Plasma exosomal miRNA bioinformatics analyses will be conducted in early (i.e., Day 14) and later (i.e., Day 30, 60, 90) responder groups. The 2 wk time point will capture the early responders and the 4, 8, and 12 wk time points will capture the remaining responder groups based on the following: Two Phase III, global, multicenter, randomized, double-blind, placebo-controlled trials (Appendix B, CIU Study 1 and CIU Study 2 data) and data of CIU patients with a starting UAS7 score of 25.3 ± 2.0 (mean ± SEM) treated with Xolair® outside of clinical trials (Metz et al., 2014), where 57% attained complete response within one week of their first treatment and a further 29% within 4 weeks (Metz et al., 2014). To address the role/mechanism of basophils in the immunopathogenesis of chronic urticaria, we will do basophil mRNA/miRNA arrays.