Chronic Airway Disease, Mucus Rheology and Exacerbations

The secondary objectives are to compare between the 2 arms: * exacerbation number according to their severity (observed throughout the duration of the study); * the evolution of the symptoms, the rheology of the sputum, and the pulmonary function (measurements repeated every three months); * medication consumption and adverse events (monitored throughout the duration of the study); * patient trajectories during follow-up; * the overall clinical improvement at the end of the study and the evolution of the quality of life (measurements repeated every 3 months); * the change in biomarkers of interest (baseline versus end of study).