Lumacaftor

Lumacaftor (USAN, codenamed VX-809) is an experimental drug for the treatment of cystic fibrosis being developed by Vertex Pharmaceuticals. The drug is designed to be effective in patients that have the F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR), the defective protein that causes the disease. F508del, meaning that the amino acid phenylalanine in position 508 is missing, is found in about 60% of cystic fibrosis patients in Europe, and in about 90% of persons with some mutation in the CFTR gene.

Results from a Phase II clinical trial indicate that patients with the most common form of genetic mutation causing cystic fibrosis&mdash;homozygous F508del&mdash;had a mean increase of 7.4% in lung function (FEV1) on a combination of lumacaftor and ivacaftor.