Lumacaftor/ivacaftor reduces exacerbations in adults homozygous for Phe508del mutation with severe lung disease.

Background: Lumacaftor/ivacaftor (LUM/IVA) improves outcomes in cystic fibrosis (CF) patients homozygous for Phe508del with ppFEV1 > 40%. There is limited safety or efficacy data in patients with ppFEV1 < 40%. We determined whether LUM/IVA in patients with ppFEV1 < 40 would reduce the rate of pulmonary exacerbations.