Gene therapy improves lung function in patients with cystic fibrosis

By Kate Bass, B.Sc.Jul 3 2015

Gene therapy was shown to provide significant benefits for patients with cystic fibrosis in a recent clinical study published in The Lancet Respiratory Medicine journal.

Cystic fibrosis is a debilitating condition that causes thick, sticky mucus to collect in the lungs. Despite frequent physiotherapy to remove the mucus, lung infections are common among patients with cystic fibrosis and lead to 90% of deaths from the disease. Cystic fibrosis is the consequence of mutations in a single gene —the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

Since only a single gene is affected, it should in theory be easy to cure cystic fibrosis by introducing a normal copy of the affected gene. However, numerous attempts at such gene therapy have failed to provide long-term clinical improvement.

The latest study provided the replacement gene via inhaled DNA molecules. The 136 patients with cystic fibrosis who participated in the study randomly received either gene therapy or placebo every month for a year. Patients were monitored using a standard test of lung function, forced expiratory volume in one second (FEV1). After a year of treatment, lung function in patients receiving the gene therapy was 3.7% better than in those who received placebo. Patients with the lowest levels of lung function at the start of the study experienced particular benefit, showing more than a 6% improvement in lung function.

Professor Eric Alton from the National Heart and Lung Institute at Imperial College London commented “Patients who received the gene therapy showed a significant, if modest, benefit in tests of lung function compared with the placebo group and there were no safety concerns”. However, he also explained that the effect was inconsistent, with some patients responding better than others.

Although the benefits observed were the result of a stabilisation of lung function rather than an actual improvement, the results of this study are still encouraging.

Professor Stephen Hyde from the Gene Medicine Research Group at the University of Oxford, explained:

Stabilisation of lung disease in itself is a worthwhile goal. We are actively pursuing further studies of non-viral gene therapy looking at different doses and combinations with other treatments, and more efficient vectors.”

This study is a landmark in the treatment of cystic fibrosis and offers hope to thousands of patients worldwide.