Cold urticaria is a potentially life-threatening disease and placebo treatment of patients does not provide protection from cold-induced systemic reactions including anaphylactic shock. Because the interim analysis showed marked clinical and statistical superiority of omalizumab compared with placebo, the study was terminated. ...omalizumab in doses of 150 mg and 300 mg resulted in a high rate of complete and partial responders in patients with cold urticaria and a pronounced overall reduction in disease activity. There were no visible differences between omalizumab and placebo; however, the viscosity of the 2 differed. ...a separate and independent unblinded study team, which did not engage in study-specific communication with the blinded study team, was responsible for the preparation and injection of the study drug. ...a sample size calculation based on previous data was not possible.