D2.470 - Potential Clinical and Laboratory Biomarkers for Predicting Omalizumab Response in Chronic Spontaneous Urticaria

Omalizumab (OMA) is an effective biological agent used in the treatment of chronic spontaneous urticaria (CSU). However, treatment response varies among patients, and reliable clinical and laboratory predictors of response remain to be clearly defined. This study aimed to evaluate the demographic, clinical, and laboratory characteristics of pediatric CSU patients receiving omalizumab and to identify potential predictors of complete treatment response.

Twenty-eight pediatric patients with CSU who received OMA therapy at Ankara Etlik City Hospital Pediatric Immunology and Allergy Clinic between October 1, 2022, and March 1, 2025, were retrospectively evaluated. Demographic characteristics, clinical features, and pre-treatment laboratory findings were obtained from hospital records. Treatment response was assessed at week 12 using the Urticaria Activity Score (UAS). Patients with UAS <7 were defined as complete responders, those with UAS 7–15 as partial responders, and those with UAS >15 as non-responders. The validated Outcome and Assessment Information Set Database (OASIS-D) rating system was used to assess responsiveness to OMA.

Of the 28 patients, 53.6% achieved a complete response, 42.9% had a partial response, and 3.6% were non-responders. At week 12, a decrease in OASIS-D scores was observed in 96% of patients. Younger age at disease onset and diagnosis was associated with significantly higher pre-treatment OASIS-D scores (Table 3). Patients who achieved a complete response had significantly lower baseline C-reactive protein (CRP) levels and neutrophil-to-lymphocyte ratio(NLR) compared to those with partial or no response (p<0.05) Although a higher Anti-TPO/Total IgE ratio was associated with lower complete response rates, this relationship did not reach statistical significance. Additionally, a history of allergic disease was significantly associated with a higher rate of complete response(Table1- 2).

Omalizumab was effective in the majority of pediatric CSU patients at week 12. Lower baseline CRP and NLR values may serve as potential predictive biomarkers for complete treatment response. Larger prospective studies are warranted to validate these findings.