Does the timing of inhaled dornase alfa matter?

In CF patients with mild or moderate lung disease, the most sensitive spirometric measure of response to dornase alfa is peripheral airflow. Cross-over studies in patients, already stabilised on dornase alfa, indicate that peripheral airflow shows greater improvement when it is administered 30 minutes before airway clearance therapy (ACT) rather than shortly after ACT. These results are consistent with the hypothesis that the major role of dornase alfa is to facilitate expectoration of sputum during ACT. When ACT is performed in the morning, efficacy and safety are similar when dornase alfa is inhaled before bedtime or upon awakening. Most patients may therefore choose the most convenient time of day to inhale dornase alfa provided that they wait at least 30 minutes before performing ACT. Further research is necessary to establish the optimum regimen in patients with more advanced lung disease.