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
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
The purpose of this study is to evaluate the safety, efficacy, pharmacokinetics (PK), and
 pharmacodynamics (PD) effects of VX-661 alone and when coadministered with ivacaftor in
 participants with cystic fibrosis (CF) who are homozygous or heterozygous for the
 F508del-CFTR mutation.
This is a Phase 2, randomized, multicenter, double-blinded, placebo-controlled, study of
 VX-661 monotherapy, and VX-661/ivacaftor co-therapy in participants with CF who are
 homozygous or heterozygous for the F508del CFTR mutation.

 This study is separated into seven groups: Group 1-7, respectively. Approximately 180
 participants were randomized in a ratio of 4:1; active drug to matching placebo in each
 group.
Inclusion Criteria:

 -  Male or female with confirmed diagnosis of CF

 -  Must have the F508del-CFTR gene mutation in both alleles (Groups 1, 2, 3, 4, 5, 6).
 Group 7 participants must have the F508del-CFTR mutation on 1 allele, and gating
 mutation G551D on the second allele and have been on their physician prescribed 150 mg
 KalydecoTM q12h (commercially available ivacaftor) for at least 28 days at the
 Screening Visit.

 -  Forced expiratory volume in 1 second(FEV1) 40% to 90% (inclusive) of predicted normal
 for age, gender, and height (Knudson standards) at screening

 -  Weight >40 kg and BMI >18.5

 -  Participants of child-bearing potential and who are sexually active must meet the
 contraception requirements.

 Exclusion Criteria:

 -  History of any illness that, in the opinion of the investigator, might confound the
 results of the study or pose an additional risk in administering study drug to the
 participant.

 -  An acute upper or lower respiratory infection, pulmonary exacerbation, or changes in
 therapy (including antibiotics) for pulmonary disease within 4 weeks before Study Day
 1.

 -  History of solid organ or hematological transplantation

 -  Participation in a clinical study involving administration of either an
 investigational or a marketed drug within 30 days or 5 terminal half-lives (whichever
 is longer) before screening

 -  History of alcohol, medication, or illicit drug abuse within 1 year prior to screening

 -  Pregnant, breast-feeding, or not willing to follow contraception requirements