Lumacaftor (VX-809) is an investigational drug developed by the Massachusetts-based pharmaceutical company Vertex for the treatment of patients who suffer from cystic fibrosis (CF) and have the F508del mutation in the CF transmembrane conductance regulator (CFTR). Currently, lumacaftor is approved by the U.S. FDA as a combined oral treatment for CF in combination with Kalydeco (ivacaftor). Lumacaftor is commercialized by Vertex under the brand name Orkambi, and Kalydeco was approved in the United States in 2012. The lumacaftor/Kalydeco combo was approved by the FDA in July 2015 for patients ages 12 and older, while the use of lumacaftor alone is still being studied by Vertex. The mechanism of action of lumacaftor is based on the interference with the F508 CFTR. The chronic disease is caused by a mutation in the gene that controls the salt transportation in the cells, resulting in thick, sticky mucus in the respiratory, digestive, and reproductive systems. To address that genetic defect, lumacaftor helps correct the mutated genes with a novel therapeutic approach. Both lumicaftor and kalydeco work by correcting the misfolded CFTR protein, the root cause of the F508del mutation, which led to the approval of the combined treatment by the FDA. However, while kalydeco alone is also approved by the FDA, the use of lumacftor alone has not yet been approved.