Overview A Study to Evaluate the Safety and Efficacy of VX-121 Combination Therapy in Subjects With Cystic Fibrosis Status: Completed Trial end date: 2019-12-10 Target enrollment: Participant gender: Summary The purpose of this study is to evaluate the safety, tolerability and efficacy of VX-121 combination therapy in subjects with cystic fibrosis (CF). Phase: Phase 2 Details Lead Sponsor: Vertex Pharmaceuticals IncorporatedTreatments: Ivacaftor