D3.426 - Predicting response to omalizumab in patients with chronic spontaneous urticaria: The first results of the global multicenter UCARE SCOPUS project

Several markers, e.g. total IgE and IgG-anti-TPO, have been reported to predict response to treatment with omalizumab in patients with chronic spontaneous urticaria (CSU); however, a simple scoring system has not yet been established. The SCOPUS project aims to close this gap by 1) investigating diagnostic accuracy of known markers and 2) developing a predictive model of the response to omalizumab treatment in CSU patients that can be translated into a clinical scoring system.

This is a retrospective global analysis of datasets of CSU patients treated at Urticaria Centers of Reference and Excellence (UCAREs). Each center provided anonymized baseline (BL) and follow-up (FU1-4) data (at 1, 3, 6, and 12 months) including patients’ demographics, clinical characteristics and laboratory parameters as well as response to omalizumab treatment. CSU patients were stratified as responders and slow, poor and/or nonresponders (NR) to omalizumab based on UCT <12 and ≥12, respectively, at BL and FU1-4.

A total of 1737 patients have been recruited to date from 39 UCAREs (female: 71.1%, mean age: 45.0 years, mean disease duration: 5.7 years and median UCT at BL: 4.0). Many patients had angioedema (53.8%), nocturnal symptoms (66.8%), chronic inducible urticaria (33.9%), autoimmune comorbidities (>20%), low total IgE (<40 kU/l, 24.4%) and positive autologous serum skin test (ASST, 45.5%). Non-Response to omalizumab was seen in 43.8% (FU1), 24.6% (FU2), 21.5% (FU3) and 15.6% (FU4) of patients. NR more often had low total IgE and positive ASST from FU1 to FU4, elevated IgG anti-TPO (FU1-2), eosinopenia (FU2) and elevated D-dimer (FU3-4) (all p<0.05).

Slow, poor and/or non-response to omalizumab treatment was seen in one in every five CSU patients and is likely to be best predicted by several markers, particularly low total IgE. Ongoing follow-up analyses of the SCOPUS data aim to develop a grading system to provide guidance on second line treatment of patients with CSU; improve the detection of patients with autoimmune CSU; and facilitate the inclusion of patients in clinical trials.