Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Pulmozyme (Roche Products)
nebuliser solution containing 2.5 mg (2500 units) per 2.5 mL
Indication: respiratory complications of cystic fibrosis
This product is a recombinant human deoxyribonuclease, manufactured using Chinese hamster ovary cells. The enzyme breaks down DNA.
Patients with cystic fibrosis produce secretions which are viscous and difficult to clear. As respiratory disease is the most frequent cause of death, it is important to keep the airways as clear as possible. The sputum of patients with cystic fibrosis contains inflammatory cells and is therefore rich in DNA. Inhaling recombinant deoxyribonuclease may therefore reduce the complications due to the accumulation of DNA in purulent sputum.
Daily treatment for 24 weeks improves FEV1 by 5-6% and parenteral antibiotics are less frequently needed. The product has been approved for use in patients between 5 and 23 years old, with a forced vital capacity (FVC) greater than 40% of the predicted value, as they are the most likely to benefit from treatment. After treatment, lung function returns to baseline levels.
Compared with patients given placebo, patients receiving the nebulised enzyme are more likely to complain of pharyngitis, laryngitis and an altered voice. Allergic reactions are possible and some patients will develop antideoxyribonuclease antibodies.
There is a need to develop protocols for the use of this product. The product information gives little guidance on whether all eligible patients should be treated, for how long and the timing of treatment in relation to other interventions such as chest physiotherapy. Treatment should continue only if there is evidence of a sustained benefit for the patient. The long term safety and efficacy are unknown.