PREFUL and 19F Lung MRI detect early effects of Mepolizumab treatment in patients with severe eosinophilic asthma

<bold>Background</bold> The treatment of severe eosinophilic asthma (SEA) is successful in most patients but predictive factors that forecast response to antibody therapy are not yet available. Phase-resolved functional lung (PREFUL) MRI as well as 19F MRI of inhaled perfluoropropane can potentially detect very early changes in the pulmonary regional ventilation dynamics and thereby have the potential as a tool for early detection of therapy response. <bold>Aim</bold> The aim of this study is to determine if early effects of Mepolizumab treatment in patients with SEA can be detected by PREFUL and 19F MRI after 3 months of therapy. <bold>Methods</bold> 19 patients with SEA were treated with Mepolizumab for 6 months. PREFUL and 19F functional MRI were performed before treatment and after 3 months. The Biologics Asthma Response Score (BARS) was used to categorize patients as either non-responders or responders after 6 months of therapy (threshold:1). <bold>Results</bold> 13 responders and 6 non-responders were identified according to the BARS. Both MRI methods showed a significant decrease of ventilation defect percentage (VDP) parameters among the responders after 3 months of therapy (p<0.05). There was a correlation between imaging parameters and FEV1%pred. (r range=0.58-0.76, p<0.05). ROC analysis showed that FEV1%pred., the 19F MRI and PREFUL MRI VDP derived parameters were similarly suited for classification of non-responders after 3 months of therapy (FEV1%pred., 19F MRI, PREFUL MRI: AUC=0.82/0.82/0.67, p≥0.3). <bold>Conclusion</bold> PREFUL and 19F MRI have great potential for early detection of therapy response in patients with severe eosinophilic asthma. Their added clinical value should be further explored in larger studies.