Airway Dysfunction, Occlusions and Remodeling: COPD Patients and Mepolizumab

The goal of this study is to evaluate the effect of mepolizumab on patients with COPD using MRI and CT imaging as well as breathing tests. The study will evaluate the response to this medication after 24 and 48 weeks of treatment. The main questions it aims to answer are: 1. Does mepolizumab improve ventilation defect percent as measured on 129-Xenon MRI in adults with COPD. 2. Does mepolizumab improve the amount of mucus plugs in the lungs as measured by lung CT in adults with COPD. Participants will: 1. Take mepolizumab by subcutaneous injection every 4 weeks for the duration of the study. 2. Visit Robarts 4 times over 48 weeks for tests and imaging.