In healthy cells, when chloride moves out of cells, water follows, keeping the mucus around the cell hydrated.
In people with the faulty CFTR protein, the chloride channels don't work properly. Chloride and water in the cells of the lungs stay trapped inside the cell, causing the mucus to become thick, sticky and dehydrated.
Overtime, the abnormal mucus builds up in the lungs and in the pancreas, which helps to break down and absorb food. Patients with cystic fibrosis have both breathing problems and problems with maintaining weight.
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.
Though improving with inhaled antibiotics and other treatments, the average life expectancy for a person with cystic fibrosis is about 39, according to the Cystic Fibrosis Foundation.
Ivacaftor is believed to work by opening up the chloride channels, allowing the water to exit the cell and the mucus to become better hydrated. For people with the more common variant, D508, ivacaftor will likely open the channels, but only if the protein is properly transported to the surface of the cell. That's where a second drug would come in, experts explained.
Vertex Pharmaceuticals, the company developing the drug, has applied for expedited U.S. Food and Drug Administration approval. If the FDA grants the company's request, that would shorten the review time to six months from the usual 10, and would mean the FDA would make a decision by April, according to Dawn Kalmar, director of product communications for Vertex.
The drug will be marketed under the brand name Kalydeco.
Dr. Pamela Davi
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