Efficacy and Safety of Omalizumab (Xolair) for Cholinergic Urticaria in Patients Unresponsive to a Double Dose of Antihistamines: A Randomized Mixed Double-Blind and Open-Label Placebo-Controlled Clinical Trial.

Background: Cholinergic urticaria (UCOL) is a highly disabling inducible urticaria triggered by an increase in core body temperature.

Objective: To explore the safety and efficacy of omalizumab in controlling UCOL.

Methods: We conducted a multicenter randomized mixed double-blind and open-label (first 4 months blinded followed by 8 months open-label) placebo-controlled clinical trial in 22 patients suffering from UCOL who were unresponsive to a double dose of antihistamines. We performed an exercise challenge test during each visit as our main outcome variable.

Results: The overall rate of exercise challenge test negative at week 48 was 31.3%, with an average increase in exercise challenge test negative rate of 2.9% points (95% CI, 1.5-4.2) per visit. Statistically significant differences in the negative exercise challenge test rate between the placebo and active intervention groups were not observed during the blinded period (first 4 months of the study). However, from the fourth dose, a progressive improvement was observed. When comparing before and after treatment, statistically significant improvements in all secondary outcome measures were noted after 4 doses (UCOL score: P = .0015; visual analog scale score: P = .0108; days with symptoms: P = .0125) and after 8 doses (UCOL score: P = .0005; chronic urticaria quality of life questionnaire: P = .0105; visual analog scale score: P = .0008; and days with symptoms: P = .0144). In the follow-up visit after the cessation of treatment, the symptoms reappeared, with positive exercise challenge test result and significant increases in all variables. Only 4 of 22 patients remained asymptomatic after 3 months of no treatment. No adverse effects were reported.

Conclusions: This randomized mixed double-blind and open-label placebo-controlled trial showed evidence of the safety and potential efficacy of omalizumab in patients with UCOL.