Evaluation of Volatile Organic Compounds in Mepolizumab Therapy

EVOC4M is a prospective observational study investigating Mepolizumab in the treatment of severe eosinophilic asthma. This study will recruit patients receiving Mepolizumab as part of their standard clinical care in an NHS commissioned Specialised Adult Severe Asthma Service. Over the course of their treatment, research data (questionnaires) and research samples (blood, breath and urine) will be collected in parallel to standard clinical measurements. Clinical studies have demonstrated blood eosinophil levels to be predictive of the magnitude of the impact of Mepolizumab in reducing severe disease exacerbations but it is appreciated that there are still treatment failures despite this selection criteria. Clinical decision and policymaking are increasingly concerned by the health economic implications of these high-cost therapies and so clinical biomarkers are now being sought for theragnostics: prediction of treatment response The study will try to identify biomarkers that will can discriminate between those that respond to Mepolizumab ("responders") and those that do not ("non-responders"). This will improve our understanding of how Mepolizumab works. In particular, the investigators are interested in exhaled volatile organic compounds (VOCs), which are measured in exhaled breath samples. Exhaled breath is safe and easy to collect and has direct contact with the organ of interest, the airways. A VOC biomarker that predicts Mepolizumab success may translate to clinical practice.