The use of human deoxyribonuclease (rhDNase) in the management of cystic fibrosis

In patients with cystic fibrosis (CF), the poor clearance of airway secretions promotes recurrent cycles of pulmonary infection and inflammation. In recent years, novel drugs have been developed to alter the properties of the secretions in an attempt to aid chest physiotherapy in improving airway clearance. Once-daily nebulised recombinant human deoxyribonuclease (rhDNase; dornase alfa; Pulmozyme (R)) is the most widely used mucoactive therapy in patients with CF. It has been shown to reduce the viscoelasticity of sputum from patients with CF and enhance the clearance of secretions. Clinical trials have shown rhDNase to be a well tolerated treatment that improves pulmonary function and reduces respiratory exacerbations. However, the response to treatment is heterogeneous and only a proportion of patients with CF actually benefit from the treatment. At present, we are unable to predict which patients will benefit from rhDNase. Many CF centers have developed formal n-of-1 trials of treatment to find out who benefits and to justify prescribing the agent. rhDNase is an expensive therapy and is mainly used in patients over the age of 5 years with moderate to severe lung disease. However, studies have shown that rhDNase may be useful in patients with milder lung disease. Comparisons with another mucoactive drug, hypertonic saline, have shown rhDNase to be more effective. Recently, it has been shown that giving rhDNase on an alternate-day basis, rather than daily, is equally effective, potentially reducing costs and treatment time.