MRI and Lung Function Measures of Benralizumab Response in Asthma

New treatments have been developed for asthma that are good at preventing asthma attacks and improving day-to-day symptoms. Alongside the development of these new drugs, there are new ways of measuring how the lung is affected by asthma. In particular, investigators have developed ways of seeing how air moves in the lungs of people with asthma, using MRI scanning. This study aims to see how quickly these new drugs result in changes in the way the lung is working, as seen in the MRI scans and other breathing tests. This will help clinicians in the future to decide who is likely to respond to these new medicines, and once patients have started taking the drugs, will help clinicians to decide whether long term treatment is likely to benefit the people receiving them. In this study, the investigators plan to do extra breathing tests and MRI scans on people who are receiving the drug as part of their usual clinical care. The study will not change an individual's treatment, but will give the investigators more information about the patients' illnesses and the way the patients' bodies respond to treatment.