This study is about understanding how well a medicine called mepolizumab (also known as NUCALA) works for adults with severe asthma. Asthma is a condition that makes it hard to breathe. Some people with asthma have a type called eosinophilic asthma, which involves certain cells in the body that can cause asthma symptoms. The study will see if NUCALA can help these people feel better and have fewer asthma problems.

To join, you need to already have asthma and be starting NUCALA. You must not have used NUCALA in the last 6 months. You should also have a certain level of breathing capacity, measured by a test called FEV1, and should not have more than 4 asthma attacks in a year. People who need certain other asthma medicines or are part of another medical study cannot join.

• This is a global study, so it might take place near you.
• You need to have started NUCALA treatment up to 7 days before joining.
• There are some restrictions on other medications you can be taking.