An increasing number of studies testing gene therapies are showing promise for treating a wide range of conditions, including cystic fibrosis. Normally in these studies, genes are injected into cells using a virus, however, scientists recently tested a new method of delivering DNA to the faulty CFTR gene in CF through what is called a cationic liposome, a fatty container that can deliver DNA directly to a cell. Results from a Phase 2 efficacy study testing this non-viral CFTR gene therapy for cystic fibrosis appeared in the July 3rd issue of the Lancet Respiratory Medicine, showing promise as a future, novel therapeutic approach for CF.
Cystic fibrosis is one of the most commonly occurring chronic diseases of the lungs in children and young adults, and can be a life-threatening disorder. Breathing is often difficult for most people with cystic fibrosis, due to a sticky mucus that builds up in the lungs and all too often leads to serious bacterial lung infections that can be fatal.
Mutations in the CFTR gene are the major cause of this mucus build-up in cystic fibrosis. Scientists have identified over 2,000 mutations in the CFTR gene that are associated with the disease, which normally presents in patients at birth. CFTR, which stands for Cystic Fibrosis Transmembrane Conductance Regulator, helps shuttle chloride ions in and out of cells, balancing salt and water in the cells that line the lungs. When CFTR is mutated, there is a dysfunction in this process that leads to the overproduction of thick mucus in the lungs.
For this new gene mutation therapy study, team of researchers led by Prof Eric W. F. W. Alton of Imperial College London, performed a randomized, double-blind, placebo-controlled, phase 2b trial. A Phase 2 trial is used to study the effectiveness of a treatment and its safety, and if the treatment is effective it can advance to the final stage before approval — Phase 3. The trial is registered on ClinicalTrials.gov under number NCT01621867.
Subjects in this study were at least 12 years old and diagnosed with cystic fibrosis and carrying CFTR gene mutations. The study participants received either the treatment or 0·9% saline (the placebo) every 28 days for a year. The main factor that the researchers planned to measure was Forced Expiratory Volume in the first second (FEV1). This is the volume of air that a person is able to force out in a second after taking a deep breath, and is a standard measurement of lung function, particularly in CF-related studies.
The gene therapy caused a statistically significant although small improvement in FEV1 compared with placebo after one year. In their report, the researchers noted that “Further improvements in efficacy and consistency of response to the current formulation are needed before gene therapy is suitable for clinical care; however, our findings should also encourage the rapid introduction of more potent gene transfer vectors into early phase trials.”
Although more refinements and more research may be needed, the non-viral gene therapy treatment could provide a next-generation therapy for people suffering from cystic fibrosis.