Overview A Phase 2 Study to Evaluate Efficacy and Safety of VX-561 in Subjects Aged 18 Years and Older With Cystic Fibrosis Status: Completed Trial end date: 2020-08-20 Target enrollment: Participant gender: Summary The purpose of this study is to evaluate the efficacy, safety, pharmacodynamic (PD) and pharmacokinetic (PK) effect of VX-561. Phase: Phase 2 Details Lead Sponsor: Vertex Pharmaceuticals IncorporatedTreatments: Ivacaftor