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. Cholinergic urticaria (UCOL) is a highly disabling inducible urticaria triggered by an increase in core body temperature. To explore the safety and efficacy of omalizumab in controlling UCOL. 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. 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. 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.