Hypereosinophilic Syndrome (HES) is a condition where your body makes too many white blood cells called eosinophils, which can cause problems in different parts of your body. This study is testing a medicine called benralizumab to see if it helps people with HES feel better. Benralizumab is given as a shot under the skin every four weeks. The study will last 24 weeks, and some people will get the medicine while others will get a placebo, which looks like the medicine but doesn't have any medicine in it.

In this study, all participants continue using their usual HES medications. After 24 weeks, everyone in the study will get benralizumab for extra time to see if it helps. To join, you need to have HES and be at least 12 years old. Some people can't join if they have other serious health problems or past treatments that didn't work.

• Study Duration: 24 weeks with follow-up period.
• Participation: Requires regular visits for checks and treatment.
• Eligibility: Must meet specific health criteria to join.

Talk to your doctor to see if this study might be a good fit for you.