Anti-viral Effects of Azithromycin in Patients With Asthma and COPD

Asthma and COPD are responsible for considerable global morbidity and healthcare costs, primarily driven by exacerbations, i.e. acute flare-ups. Hence there is a clear need for better interventions preventing exacerbations. A majority of exacerbations are driven by infections, and in particular viral infections. Importantly, the anti-viral defense in asthma and COPD seems compromised, with a relative inability to combat infections, but also a disproportionate inflammatory response to infections, i.e. an increased immunoreactivity involving release of epithelial 'alarmins', such as IL-33 and thymic stromal lymphopoietin (TSLP). Long-term low dose macrolides have been shown to reduce exacerbations in both diseases and are increasingly used clinically, but the mechanism of action is unknown. Macrolides have anti-viral properties in vitro, however their anti-viral properties have not been established in patients with asthma and COPD during exacerbations. The purpose of this study is to investigate the anti-viral and anti-inflammatory effects in the airways, as well as the effects of azithromycin on the lung microbiome. In order to study these effects, the key endpoints in this trial will need to be obtained from bronchoscopic sampling of bronchial brushes, bronchial biopsies and BAL. But performing bronchoscopies during acute exacerbations, when patients are infected with respiratory viruses, is difficult in view of safety. Therefore, this study on in vitro rhinovirus responses of human bronchial epithelial cells before and after in vivo treatment with macrolides represents a novel model to study treatment effects on immunoreactivity during exacerbations. The investigators hypothesize that long-term treatment with low dose AZM modulates the immune response to viral infections, with an increased interferon release, in patients with asthma and COPD with an exacerbation history. The investigators also speculate that AZM treatment leads to a decreased release of the epithelial alarmins (e.g. IL-33 and TSLP) in response to viral infection, in patients with asthma and COPD with an exacerbation history. Furthermore, treatment effects of low dose AZM on functional and compositional changes of bacterial communities of the respiratory- and gastrointestinal tract, and their association with changes in immunoreactivity will be studied. This trial offers the opportunity to study potential biomarkers and surrogate endpoints, but also to identify the anti-inflammatory effects of azithromycin on a mechanistic level. This study is a randomized, double-blind, placebo-controlled trial. It includes a enrolment period of maximum 4 weeks, with a bronchoscopy before and after 12 weeks of treatment (500mg azithromycin or placebo, 3 times per week).