D1.505 - Impact of patient factors on the stability of anti-IgE treatment response in chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU)  is a debilitating condition, and anti-IgE treatment is a key treatment option after antihistamines (AH) fail. Assessment of  the response stability during treatment  and evaluating the predictors of relapse after treatment discontinuation is crucial for optimizing treatment strategies.

The cohort included 146 patients with AH resistant CSU on anti-IgE treatment. Response stability was assessed using UAS7 (Urticaria Activity Score) at weeks 4, 16, and 24, UAS7 ˂7 indicated an optimal response. Additionally, a subgroup of patients who experienced symptom recurrence within the first year after therapy discontinuation was analyzed. Quantitative and categorical variables, including baseline total IgE (tIgE) levels, comorbidities, and the presence of chronic inducible urticaria (CIndU), were evaluated to identify factors associated with response stability and relapse.

By week 4, an optimal response to anti-IgE treatment was observed in 38.6% of patients, increasing to 65.3% at week 16 and 74.3% at week 24. Among non-responders at week 4, 58% achieved an optimal response by week 24. Patients who achieved response by week 16 maintained a stable response through week 24. Negative predictors of achieving a complete response to omalizumab at week 4 included comorbid asthma, allergic rhinitis, elevated IgG anti-TPO, low tIgE, longer CSU duration, and comorbid CIndU. By week 24, only comorbid CIndU and the combination of elevated IgG anti-TPO with low tIgE remained significant, each reducing the likelihood of complete response by 20%. Relapse analysis revealed that patients with lower baseline UAS7 scores, indicating lower initial disease activity, were more likely to experience recurrence. Relapses were absent in patients with comorbid symptomatic demographism.

Most patients with CSU responded rapidly to anti-IgE treatment, and the achieved response was maintained during the treatment period. Comorbid CIndU and the combination of elevated IgG anti-TPO with low tIgE were the main predictors of poor response at week 24. Lower baseline UAS7 scores increased the risk of relapse after discontinuation.