A Study to Evaluate the Pharmacodynamics, Pharmacokinetics, Safety, and Efficacy of UB-221 IV Infusion as an add-on Therapy in Patients With Chronic Spontaneous Urticaria

This is a phase II, double-blind, randomized, parallel group, placebo-controlled study to evaluate the pharmacodynamics, pharmacokinetics, efficacy, and safety of 2-dose UB-221 IV infusion as an add-on therapy in patients with chronic spontaneous urticaria. The study will be conducted at multiple study centers in Taiwan. Approximate 25 eligible subjects will be randomized into two UB-221 (5 \&10 mg/kg) and one placebo (saline) cohorts in a ratio of 2:2:1. The study consists of a pre-screening period (Day -42 to -29), a screening period (Day -28 to -1), a dose 1 period (Day 0 to 83), and a dose 2 period (Day 84 to 196).