Residual Exacerbations With Mepolizumab

This study looks at why some patients with severe asthma continue to have flare-ups (exacerbations) even while taking mepolizumab, a biologic drug that reduces a type of white blood cell called eosinophils that drives asthma attacks. Researchers want to understand what causes these remaining flare-ups. **You may be eligible if...** - You have a confirmed diagnosis of severe asthma as defined by Canadian guidelines - You are eligible for or already taking mepolizumab - You are willing and able to sign the informed consent form **You may NOT be eligible if...** - You have another respiratory disease in addition to asthma - You have a condition such as eosinophilic granulomatosis with polyangiitis (EGPA) or hypereosinophilic syndrome that could confuse the study results Talk to your doctor to see if this trial is right for you.