This clinical trial is focused on studying a condition called eosinophilic granulomatosis with polyangiitis (eGPA). This is a rare disease that causes inflammation of blood vessels, which can lead to damage in various organs. The study will use a treatment called mepolizumab, which is given as an injection under the skin. Mepolizumab is a type of protein that helps to reduce inflammation by targeting specific cells in the immune system.
The purpose of the study is to see how mepolizumab affects the nasal microbiome, which is the community of bacteria and other microorganisms living in the nose, and the immune response in people with eGPA. Participants in the study will receive mepolizumab treatment, and researchers will observe changes in the nasal microbiome and immune response over time. The study will last for a period of 36 months, with regular check-ups to monitor the effects of the treatment.
By participating in this study, researchers hope to better understand how mepolizumab can help restore a healthy balance of microorganisms in the nose and improve the immune response in patients with eGPA. This could lead to better treatment options for managing the disease in the future.



The Netherlands