Omalizumab Discontinuation in Chronic Spontaneous Urticaria: Effectiveness and Predictors of Response and Relapse Comparing Abrupt Cessation and Dose Spacing in a Retrospective Real-Life Study.

BACKGROUND: Omalizumab is a highly effective third-line treatment for chronic spontaneous urticaria (CSU) refractory to antihistamines. However, disease relapse upon cessation is a significant clinical challenge. Real-world evidence comparing different discontinuation strategies is scarce. METHODS: This retrospective, multicenter, real-world study evaluated 199 patients with refractory CSU treated with omalizumab (300 mg/month) in the Piedmont-Aosta Valley region. We assessed effectiveness using Urticaria Activity Score (UAS/UAS7) and Dermatology Life Quality Index (DLQI). The primary outcomes were response rates, relapse rates after abrupt discontinuation versus gradual dose spacing, and predictors of these outcomes. RESULTS: Omalizumab demonstrated high effectiveness, achieving a complete response rate of 71% after the first treatment cycle, with drastic reductions in mean UAS7 (from 28.8 to 4.3) and DLQI (from 25.3 to 0.8) by month 4. Abrupt discontinuation resulted in a high relapse rate of 73.7%, with a short median time to recurrence of 2 months. Multivariate analysis found no significant baseline predictors of response. Counterintuitively, a higher baseline UAS7 was associated with a lower risk of relapse. A subgroup of 48 patients, characterized as "super-responders," underwent gradual dose spacing. This group achieved a significantly lower relapse rate of 27.1% after abrupt cessation, without significant symptomatic worsening during tapering. CONCLUSIONS: Omalizumab is an effective control therapy for CSU in a real-world setting. Abrupt discontinuation leads to rapid relapse in the majority of patients. Gradual dose spacing represents a promising strategy to prolong remission and reduce drug burden, particularly in patients exhibiting excellent initial therapeutic response.