Predictors of treatment control in severe chronic urticaria treated with omalizumab.

Background: Real-life clinical research on biomarkers that predict therapy outcomes of severe chronic spontaneous urticaria patients receiving omalizumab (OMA) therapy is still limited. For this reason, we aimed to identify biomarkers that predict the response to OMA treatment.

Methods: A single-center, observational, retrospective review of patients with severe chronic urticaria treated with OMA from January 2015 to January 2023 in a Portuguese Immunology and Allergy Department. One-way ANOVA and linear regression were used.

Results: Data on 56 OMA-treated chronic spontaneous urticaria patients shows patients can be divided into 3 groups according to their response to OMA. The first group of 26 patients (46.4%) successfully reduced their IMA dose without experiencing any rebound effects. The second group of 19 (33.9%) patients achieved disease control but could not tolerate a progressive dose reduction, and the third group of 11 (19.6%) patients, required a higher dose to achieve disease control. In group 1, patient age and a favorable clinical response had a positive correlation (P = 0.008). The patient's age was also correlated to the time interval until a dose reduction was tolerated (r = 0.69; P = 0.005). There was also a negative correlation between the ratio: thyroid peroxidase antibodies/total-IgE and a favorable clinical response (r = -0.74; P = 0.021). In group 2, thyroid peroxidase antibodies were negatively correlated with a favorable clinical response (r = -0.55; P = 0.027). In group 3, anti-double-stranded DNA was negatively correlated with a favorable clinical response (r = -0,97; P = 0,007).

Conclusion: Our study suggests that older patients experience higher success rates with OMA compared to younger individuals, but increasing age is also associated with a longer interval before achieving successful dose reduction. Potential markers of resistance to OMA identified in our cohort included elevated levels of IgG-antithyroid peroxidase antibodies, positive anti-dsDNA antibodies, and a higher IgG-antithyroid peroxidase/total-IgE ratio.