About Cystic Fibrosis and the Combination of VX-809 and IvacaftorCystic fibrosis is a rare, life-shortening genetic disease affecting approximately 70,000 people worldwide, including 30,000 people in the United States and 35,000 in Europe. The median predicted age of survival for a person with CF born today is between 34 and 47 years, but the median age of death remains in the mid-20s. The most common cause of death among people with CF is lung disease, which results from recurring infections and chronic lung inflammation. CF is caused by a defective or missing CFTR protein resulting from mutations in the cystic fibrosis transmembrane conductance regulator ( CFTR) gene. Children must inherit two defective CFTR genes — one from each parent — to have CF. There are more than 1,800 known mutations in the CFTR gene. Some of these mutations, which can be determined by a genetic, or genotyping test, lead to CF by creating non-working or too few CFTR protein at the cell surface. The absence of working CFTR protein results in poor flow of salt and water into and out of the cell in a number of organs, including the lungs. In people with the most common mutation in the CFTR gene, F508del, little-to-no CFTR protein reaches the cell surface. As a result, thick, sticky mucus builds up and blocks the passages in many organs, leading to a variety of symptoms. In particular, mucus builds up and clogs the airways in the lungs, causing chronic lung infections and progressive lung damage. VX-809, known as a CFTR corrector, is believed to help CFTR protein reach the cell surface. Ivacaftor, known as a CFTR potentiator, keeps the CFTR protein channels on the cell surface open longer to increase the flow of salt and water into and out of the cell. Globally, nearly half of people with CF have two copies of the F508del mutation and an additional one-third have one copy of the F508del mutation. As announced in January 2013, the FDA granted Breakthrough Therapy Designation to the combination regimen of VX-809 with ivacaftor for cystic fibrosis.