Overtime, the abnormal mucus builds up in the lungs and in the pancreas, which helps to break down and absorb food, causing both breathing and digestive problems.
In the lungs, the accumulation of the mucus leaves people prone to serious, hard-to-treat and recurrent infections. Overtime, the repeated infections destroy the lungs.
The average life expectancy for a person with cystic fibrosis is about 37, according to the Cystic Fibrosis Foundation.
While inhaled antibiotics and other treatments have led to substantial improvements in life expectancy, no treatments specifically target the CFTR protein. That's where VX-770 comes in, said Dr. Frank Accurso, lead study author and a professor of pediatrics at University of Colorado Denver and The Children's Hospital in Denver.
With $76 million in funding from the Cystic Fibrosis Foundation, Vertex Pharmaceuticals screened hundreds of thousands of molecules in the lab, searching for those that might work to alter the chloride channels in cystic fibrosis cells.
"You can think of the gate as being closed," Accurso said. "What this treatment does is open up the gate, allowing the chloride channel to open and the water to get out."
In the Phase II trial, 39 adults with cystic fibrosis took either the drug or a placebo for two weeks, and then again for 28 days. All patients had the G551D mutation, present in 4 to 5 percent of patients, according to the study.
Tests showed that not only did lung function improve, participants reported feeling better.
Levels of chloride in sweat also fell, indicating the drug is working on the cellular level to better regulate the release of chloride.
"That is telling us that we have improved the function of the CFTR," Accurso said.
The primary objective of the study was to evaluate the safety and tolerability of the drug. There was no difference in the frequency of reported adverse events among those taking the drug
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