Cystic fibrosis is a genetic disease that causes a thick, sticky mucus to build up in the lungs and digestive tract. A clinical trial of a new drug called denufosol found that those given the medication for six months prevented some of the accumulation and improved performance on lung tests.
Cystic fibrosis is caused by a genetic mutation that disrupts the cystic fibrosis transmembrane regulator (CFTR) protein, an ion channel. Denufosol tetrasodium inhalation solution works by correcting ion transport in patients to enhance airway hydration and mucus clearance by increasing chloride secretion, inhibiting sodium absorption and increasing ciliary beat frequency.
Frank J. Accurso MD of the University of Colorado and colleagues included about 350 children with cystic fibrosis aged five and older in the study called TIGER-1, The Transport of Ions to Generate Epithelial Rehydration. All had a forced expiratory volume (FEV1) at least 75% of normal, indicating normal to mildly impaired lung function characteristic of early cystic fibrosis.
The patients were randomized to receive either 60 milligrams of inhaled denufosol three times daily or a matching placebo for 24 weeks. This was followed by another 24-week open-label safety extension phase.
The patients on the new medication had increase in FEV1 of 0.048 L, approximately 2% over baseline. In addition, the researchers found further lung improvement by 0.115L by the end of the open-label phase. The placebo group, when switched over to denofusol in the open-label phase, also improved by a mean 0.078 L in FEV1.
Big improvements weren't expected, says Accurso, because the drug is primarily designed to prevent or delay loss of lung function rather than act as a rescue therapy.
Denufosol appeared to be safe without serious adverse events or impaired growth of the young patients, suggesting it could be suitable as an early intervention. Intervention for cystic fibrosis early in its course has the potential to delay or prevent progressive changes that lead to irreversible airflow obstructions, the researchers say in their study published in the American Journal of Respiratory and Critical Care Medicine.
A second phase III trial, which is called TIGER-2, is ongoing which will incorporate a longer placebo-controlled treatment phase. Inspire Pharmaceuticals is targeting a potential US commercial launch of the drug for 2012, pending FDA approval.
Accurso FJ, et al “Denufosol Tetrasodium in Patients with Cystic Fibrosis and Normal to Mildly Impaired Lung Function” Am J Respir Crit Care Med 2011.