Ivacaftor is a medication used to treat cystic fibrosis in people with certain mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene (primarily the G551D mutation), who account for 4–5% cases of cystic fibrosis. It is also included in combination medications, lumacaftor/ivacaftor, tezacaftor/ivacaftor, and elexacaftor/tezacaftor/ivacaftor which are used to treat people with cystic fibrosis.Ivacaftor was developed by Vertex Pharmaceuticals in conjunction with the Cystic Fibrosis Foundation and is the first medication that treats the underlying cause rather than the symptoms of the disease. It was approved by the U.S. Food and Drug Administration (FDA) in January 2012. It is one of the most expensive drugs, costing over US$300,000 per year, which has led to criticism of the high cost. The combination drug lumacaftor/ivacaftor was approved by the FDA in July 2015.Cystic fibrosis is caused by any one of several defects in the CFTR protein, which regulates fluid flow within cells and affects the components of sweat, digestive fluids, and mucus. One such defect is the G551D mutation, in which the amino acid glycine (G) in position 551 is replaced with aspartic acid (D). G551D is characterized by a dysfunctional CFTR protein on the cell surface. In the case of G551D, the protein is trafficked to the correct area, the epithelial cell surface, but once there the protein  cannot transport chloride through the channel.
There was negligible urinary excretion of ivacaftor as unchanged parent. The apparent terminal half-life was approximately 12 hours following a single dose in the fed state. The apparent clearance (CL/F) of ivacaftor was similar for healthy subjects and patients with CF. The mean (±SD) of CL/F for the 150 mg dose was 17.3 (8.4) L/h in healthy subjects at steady state. Society and culture
Legal status
The U.S. Food and Drug Administration (FDA) approved ivacaftor in January 2012, and soon afterwards so too did the European Medicines Agency (EMA) and Canada and across some European countries.Lumacaftor/ivacaftor was approved by the FDA in July 2015, under breakthrough therapy status and under a priority review. Economics
The cost of ivacaftor is US$311,000 per year, roughly similar to the price of other medications for extremely rare diseases. In the first nine months of its second year on the market (2014), ivacaftor sales were $339M, representing 54% of Vertexs product sales revenue. During the same period, total drug development expenses were $458M, most of which was spent on cystic fibrosis-related research.An editorial in JAMA called the price of ivacaftor "exorbitant", citing the support by the Cystic Fibrosis Foundation in its development and the contribution made by fundamental scientific research performed by the National Institutes of Health and relied upon by Vertex in its cystic fibrosis drug discovery programs.