Predictors of Super/Poor Omalizumab Response in Chinese Refractory Chronic Spontaneous Urticaria.

UNLABELLED: <p>

Introduction

Omalizumab is an effective treatment for antihistamine-refractory chronic spontaneous urticaria (CSU), although treatment responses vary significantly. While fast and slow responders are well characterized, the profile of super responders (SRs) remains poorly understood. This study aimed to identify clinical and laboratory predictors of super response (SR) and poor/non-response (PR) to omalizumab in refractory CSU.

METHODS

This retrospective study analyzed 307 CSU patients treated with omalizumab at a UCARE center between January 2023 and December 2024. SR was defined as achieving Urticaria Activity Score (UAS) = 0 within 1 week and sustained control (UAS7 ≤6, Urticaria Control Test [UCT] >12); PR was defined as UCT <12 after three injections. Demographic, clinical, and laboratory parameters were compared between response groups.

RESULTS

SR patients (n = 138) had lower rates of concomitant chronic inducible urticaria (CIndU) (26.8% vs. 48.5%, p < 0.05), higher total immunoglobulin E (IgE) (113.0 IU/mL), and elevated D-dimer. PR patients (n = 35) were older (median 52.0 years) and had higher angioedema rates (65.5%), lower atopy prevalence (47.1%), higher UAS7 scores, lower IgE (53.5 IU/mL), and higher autologous serum skin test (ASST) positivity (61.5%). Multivariate analysis identified male sex as protective for SR (odds ratio [OR] = 0.556, p = 0.025), while concomitant CIndU predicted non-SR (OR = 2.357, p = 0.001). Predictors of PR included body mass index (BMI) ≥28 kg/m2 (OR = 5.147, p = 0.023), angioedema (OR = 3.309, p = 0.042), and ASST positivity (OR = 4.174, p = 0.011); atopy was protective (OR = 0.299, p = 0.025).

CONCLUSION

Male sex and absence of CIndU predict super response to omalizumab, while high BMI, angioedema, and ASST positivity predict poor response. Atopy is associated with better omalizumab response. These findings support personalized treatment strategies in refractory CSU, though further multiethnic validation is warranted. </p>.