A two-year randomized, placebo-controlled trial of dornase alfa in young patients with cystic fibrosis with mild lung function abnormalities

Objective: Our objective was to determine whether long-term treatment of young patients with cystic fibrosis (CF) with dornase alfa maintains lung function and reduces respiratory tract exacerbations. Study design: This was a 96-week, randomized, double-blind, placebo-controlled trial involving 49 CF centers. Inclusion criteria were age 6 to 10 years and forced vital capacity greater than or equal to 85% predicted. Patients were excluded for hospitalization for complications of CF within 2 months and use of dornase alfa within 6 months. Patients were treated with dornase alfa 2.5 mg or placebo once daily with a jet nebulizer and a compressor. Results: Patients were randomized, 239 to dornase alfa and 235 to placebo. At baseline the mean age was 8.4 years, the mean forced expiratory volume in I second 95% predicted, the mean forced expiratory flow, midexpiratory phase 85% predicted, and the mean forced vital capacity 102% predicted. At 96 weeks the treatment benefit for dornase alfa compared with placebo in percent predicted (mean SE) was 3.2 +/- 1.2 for forced expiratory volume in I second (P = .006), 7.9 +/- 2.3 for forced expiratory flow between 25% and 75% of vital capacity (P = .0008), and 0.7 +/- 1.0 for forced vital capacity (P = .51). The risk of respiratory tract exacerbation was reduced by 34% in patients who received dornase alfa (relative risk 0.66, P = .048). There was no statistically significant difference between the groups in changes in weight-for-age percentile. Adverse event profiles for the treatment groups were similar. Conclusions: Treatment of young patients with CF,,vith dornase alfa maintains lung function and reduces the risk of exacerbations over a 96-week period.