The ECFS-CTN cannot guarantee that the information provided here is comprehensive. Please go to the ClinicalTrials.gov link for detailed and up-to-date information on study background, eligibility criteria, study design, outcome measures, study status, participating sites, sponsor contact information and timelines.

You can also contact the CTN coordinating centre for additional information: ECFS-CTN@uzleuven.be (link sends e-mail)

Study Name on
ClinicalTrials.gov (link is external)
A Phase 3 Study to Evaluate the Efficacy and Safety of Ivacaftor and VX-661 in Combination With Ivacaftor 
in Subjects Aged 12 Years and Older With Cystic Fibrosis, Heterozygous for the F508del-CFTR Mutation

Study DrugVX-661/ ivacaftor
Type of Study DrugCFTR modulator
Study TitleA Phase 3, Randomized, Double-Blind, Placebo-Controlled, Crossover Study to Evaluate
the Efficacy and Safety of Ivacaftor and VX-661 in Combination With Ivacaftor in Subjects Aged 12 Years and Older 
With Cystic Fibrosis, Heterozygous for the F508del-CFTR Mutation, and a Second Allele With a CFTR Mutation
Predicted to Have Residual Function
Study Phase3
Study SponsorVertex

Link on
clinicaltrials.gov (link is external)

https://clinicaltrials.gov/ct2/show/study/NCT02392234 (link is external)

Participating ECFS-CTN sitesPlease contact ecfs-ctn@uzleuven.be for most recent sitelist 
Age12 Years and Older