Study of VX-661 Alone and in Combination With Ivacaftor in Subjects Homozygous or Heterozygous to the F508del-Cystic Fibrosis Transmembrane Conductance Regulator(CFTR) Mutation

A Phase 2, Multicenter, Double-Blinded, Placebo Controlled Study to Evaluate Safety, Efficacy, Pharmacokinetics, and Pharmacodynamics of VX-661 Monotherapy and VX-661/Ivacaftor Cotherapy in Subjects With Cystic Fibrosis, Homozygous or Heterozygous for the F508del-CFTR Mutation