A Study to Assess the Efficacy, Safety, and Tolerability of CAT-354 in Subjects With Asthma

This is a randomized, stratified, double-blind, placebo-controlled, multicenter, multinational study in subjects with uncontrolled asthma despite optimal treatment. Following confirmation of eligibility, subjects will be randomly assigned on Day 0, to 1 of 4 dose groups 1 mg/kg CAT-354, 5 mg/kg CAT-354, 10 mg/kg CAT or Placebo to match all doses of CAT-354. Doses of the assigned treatment will be administered on three occasions 28 days apart. Subjects will be assessed for efficacy, including airway hyper-responsiveness (AHR), safety, pharmacokinetic, pharmacodynamics and immunogenicity until Day 84 post-first dose.