A Crossover, Randomized, Controlled Trial of Dornase Alfa Before Versus After Physiotherapy in Cystic Fibrosis

Abstract

Although dornase alfa is a widely used, aerosolized, mucolytic agent in patients with cystic fibrosis (CF), its efficacy in relation to the timing of physiotherapy has not been tested. We sought to determine whether dornase alfa is more efficacious when it is administered 30 minutes before versus 30 minutes after physiotherapy/positive expiratory pressure (PEP) therapy in clinically stable children. Using a crossover, randomized, double-blind, and placebo-controlled trial, we undertook a 6-week study of the efficacy of dornase alfa in relation to the timing of physiotherapy at home. There were 2 treatment orders. Dornase alfa before + placebo after physiotherapy/PEP for 2 weeks was followed by a 2-week washout and then the reverse order placebo before and dornase alfa after physiotherapy/PEP for the final 2 weeks. The second treatment order reversed the placebo and dornase alfa therapy for the first and last 2-week blocks. The main outcome measures used included the change in predicted percentage of forced expiratory volume in 1 second (FEV1), a composite quality of well-being score (QWB), and a measure of aerobic fitness (maximal oxygen consumption, [VO2max]), determined using shuttle testing. Fifty-two patients who had CF (27 female) with mild to moderate suppurative lung disease, were a mean +/- SD age of 10.7 +/- 3.2 years, had Shwachman scores of 86 +/- 11.8, had predicted FEV1 of 83% +/- 18%, had quality of well-being score of 0.76 +/- 0.08, and had VO2max of 42.6 +/- 6.3 ml/kg per min were enrolled. Fifty patients completed the study. Intention-to-treat analysis was used. Nonsignificant mean (95% confidence interval) differences in FEV1 (0.02 L [-0.05 to 0.10]), VO2max (-0.75 ml/kg per min [-1.85 to 0.35]), and QWB (0.005 [-0.94 to 0.0028]) for dornase alfa after physiotherapy/PEP were detected. A post hoc analysis showed that patients who were colonized persistently with Pseudomonas aeruginosa had a significantly greater improvement in FEV1 (0.12 L [0.23 to 0.01] vs -0.04 L [0.05 to -0.13]) when dornase alfa was administered after physiotherapy/PEP. Dornase alfa is equally efficacious when delivered before or after physiotherapy/PEP in patients with CF. Patients who are colonized persistently with P aeruginosa may derive more improvement in FEV1 when dornase alfa is delivered after physiotherapy/PEP.