Lumacaftor/ivacaftor and elexacaftor/tezacaftor/ivacaftor are approved in the United States for the treatment of cystic fibrosis (CF) in those with homozygous or compound heterozygous F508del cystic fibrosis transmembrane conductance regulator (CFTR) mutations, respectively. The gene discussed is CFTR; the disease is cystic fibrosis.