Small airway deposition of dornase alfa during exacerbations in cystic fibrosis; a randomized controlled clinical trial

Abstract

Small airway obstruction is important in the pathophysiology of cystic fibrosis (CF) lung disease. Additionally, many CF patients lose lung function in the long term as a result of respiratory tract exacerbations (RTEs). No trials have been performed to optimize mucolytic therapy during a RTE. We investigated whether specifically targeting dornase alfa to the small airways improves small airway obstruction during RTEs. In a multi-center, double-blind, randomized controlled trial CF patients hospitalized for a RTE and on maintenance treatment with dornase alfa were switched to a smart nebulizer. Patients were randomized to small airway deposition (n = 19) or large airway deposition (n = 19) of dornase alfa for at least 7 days. Primary endpoint was forced expiratory flow at 75% of forced vital capacity (FEF75 ). Spirometry parameters improved significantly during admission, but the difference in mean change in FEF75 between treatment groups was not significant: 0.7 SD, P = 0.30. FEF25-75 , FEV1 , nocturnal oxygen saturation and diary symptom scores also did not differ between groups. This study did not detect a difference if inhaled dornase alfa was targeted to small versus large airways during a RTE. However, the 95% confidence interval for the change in FEF75 was wide. Further studies are needed to improve the effectiveness of RTE treatment in CF.