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

INTRODUCTION: 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. METHODS: 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 ). MAIN RESULTS: 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. CONCLUSIONS: 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.

Improved treatment response to dornase alfa in cystic fibrosis patients using controlled inhalation.

Better treatment of obstructed small airways is needed in cystic fibrosis. This study investigated whether efficient deposition of dornase alfa in the small airways improves small airway obstruction. In a multicentre, double-blind, randomised controlled clinical trial, cystic fibrosis patients on maintenance treatment with 2.5 mL dornase alfa once daily were switched to a smart nebuliser and randomised to small airway deposition (n = 24) or large airway deposition (n = 25) for 4 weeks. The primary outcome parameter was forced expiratory flow at 75% of forced vital capacity (FEF(75%)). FEF(75%) increased significantly by 0.7 sd (5.2% predicted) in the large airways group and 1.2 sd (8.8% pred) in the small airways group. Intention-to-treat analysis did not show a significant difference in treatment effect between groups. Per-protocol analysis, excluding patients not completing the trial or with adherence <70%, showed a trend (p = 0.06) in FEF(75%) Z-score and a significant difference (p = 0.04) between groups in absolute FEF(75%) (L · s(-1)) favouring small airway deposition. Improved delivery of dornase alfa using a smart nebuliser that aids patients in correct inhalation technique resulted in significant improvement of FEF(75%) in children with stable cystic fibrosis. Adherent children showed a larger treatment response for small airway deposition.