CHARACTERISTICS OF PATIENTS WITH CHRONIC SPONTANEOUS URTICARIA WHO ARE EARLY RESPONDERS TO OMALIZUMAB

Introduction

Omalizumab, an anti-immunoglobulin E (IgE) antibody, is approved for the treatment of H1-antihistamine-refractory chronic spontaneous urticaria (CSU), and studies suggest that time to response may vary across patient subgroups. Patient characteristics associated with an early response to omalizumab are not well understood.

Methods

We conducted a post-hoc analysis of pooled phase 3 ASTERIA I/II trials (NCT01287117/01292473). Patients with H1-antihistamine-refractory CSU received omalizumab or placebo for up to 24 weeks. Response to omalizumab was defined as a weekly Urticaria Activity Score (UAS7) of ≤6. Baseline demographics and clinical characteristics were assessed among early responders and non-responders at Week 4. Analyses were conducted within the omalizumab 300 mg treatment group by evaluating baseline variables one at a time and P values were generated using 2-sample t-tests for continuous baseline variables and chi-square tests for categorical variables.

Results

A higher proportion of early responders had a negative chronic urticaria (CU) index or angioedema at baseline versus non-responders (for negative CU index, 87.0% [n=60/69] vs 66.7% [n=60/90], P=0.0032; for angioedema, 51.4% [n=36/70] vs 33.3% [n=30/90], P=0.0211). Among patients with both a negative CU index and angioedema at baseline, 68.3% were early responders (n=28/41); however, there was only 1 early responder among patients with the opposite characteristics (both a positive CU index and no angioedema, 7.1% [n=1/14]). Overall safety results for ASTERIA I/II: Maurer NEJM 2013;368:924-35 and Saini JID 2015;135;67-75.

Conclusions

Patients with CSU with a negative CU index and/or angioedema at baseline may be more likely to be early responders after initiating treatment with omalizumab 300 mg.