Study to Evaluate the Safety, Pharmacology and Efficacy of WIN378 in Adults With Moderate or Severe Asthma

The main purpose of this global study is to assess whether WIN378, an ultra-long-acting medicine for people with asthma, reduces the annualized rate of asthma exacerbations using the doses identified from an interim analysis of Part A of the study. WIN378 blocks the action of a protein called TSLP, which causes inflammation in the lung and may contribute to asthma control and symptoms. The study has two parts. Part A is evaluating three doses of WIN378 in adults with moderate or severe asthma to evaluate: 1) how WIN378 is handled by your body (pharmacokinetics), 2) the safety of WIN378 and 3) efficacy (markers of asthma inflammation (in your breath and in your blood), lung function and asthma control. An interim analysis of Part A data was used to select two doses of WIN378 for Part B. Part B will compare the two selected doses of WIN378 with placebo in adults with severe uncontrolled asthma. The main purpose of Part B is to assess whether WIN378 reduces the annualized rate of asthma exacerbations. In addition, it aims to evaluate whether WIN378 can improve lung function, quality of life, asthma control and other important efficacy measures. Furthermore the study will evaluate the safety and tolerability of WIN378 versus placebo.