Cystic fibrosis typically reduces lung function, and the production of thick sticky mucus leads to chronic infection.
An international research team has demonstrated that a combination of two different drugs targeting the most common genetic cause of cystic fibrosis helped to improve lung function and reduce the rate of pulmonary exacerbations.
"These results represent a further major advance in finding treatments which correct the basic problem in cystic fibrosis and improve the lives of patients living with the condition," reports Prof. Stuart Elborn, a co-author of the study from Queen's University in Belfast, Northern Ireland.
Cystic fibrosis is a hereditary condition that causes cells producing mucus, sweat and digestive juices to secrete thicker and more sticky fluids than normal. These secretions often restrict and block ducts and tubes, particularly in the lungs and pancreas, severely inhibiting the lungs and digestive system.
The disorder is a life-threatening one. In the lungs, thick mucus reduces lung function and leads to chronic infection while in the pancreas the mucus prohibits enzymes from reaching the gut to enable the complete digestion of food.
Cystic fibrosis is caused by genetic mutations that fall into six different functional categories. The most common therapeutic target for the condition is the F508del mutation - almost half of patients with cystic fibrosis in the US have two copies of this mutation.
One drug, ivacaftor, is approved by the US Food and Drug Administration (FDA) for the treatment of a less common cystic fibrosis mutation, but had not previously been found effective in treating patients with two copies of the F508del mutation.
However, a phase 2 study indicated that combining ivacaftor with another drug called lumacaftor could be beneficial to patients with this mutation. As a result, the researchers conducted two phase 3 trials to evaluate how effective this drug combination would be.
Study findings represent 'an exciting step forward'
A total of 1,108 patients with the most common form of cystic fibrosis participated in the randomized, double-blind, placebo-controlled study. Participants were aged 12 and above and were treated for 24 weeks in centers across the world.
The researchers found that treatment with the new drug combination led to a reduction in the number of hospital courses of antibiotic treatment required, alongside improvements in breathing test results, weight and quality of life.
Improvements in the nutritional status of the patients with cystic fibrosis were hypothesized by the researchers to reflect either better caloric absorption or a reduction in energy expenditure attributed to ameliorating the effects of lung disease.
"Just a few years ago, ivacaftor became the only FDA-approved drug for the genetic defect in cystic fibrosis, but it only works for genetic mutations found in a small portion of cystic fibrosis patients," states study author Dr. Susanna McColley, professor of pediatrics at Northwestern University Feinberg School of Medicine, IL.
"Our study showed that combining ivacaftor with lumacaftor helps patients with the most common cystic fibrosis mutation. This is an exciting step forward."
Dr. McColley says that more analyses and longer-term data are required for the team to ascertain whether this treatment can alter the course of cystic fibrosis and further extend the life expectancy of patients with the condition. At present, the median life expectancy for patients with the disease is 37 years.
Last week, the FDA Pulmonary-Allergy Drugs Advisory Committee met to consider the results of the study, published in New England Journal of Medicine. Final approval from the committee is still pending.
Previously, Medical News Today reported on a study describing the role of "mini-lungs" in cystic fibrosis research. A team at the University of Cambridge in the UK has been able to successfully create organoid models in the laboratory as a new way to research and test new drugs.