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Clinical trials identifierNCT02347657
Study codesVX14-661-106, EVOLVE
Study titleA Phase 3, Randomized, Double Blind, Placebo Controlled, Parallel Group Study to Evaluate the Efficacy and Safety of VX-661 in Combination With Ivacaftor in Subjects Aged 12 Years and Older With Cystic Fibrosis, Homozygous for the F508del CFTR Mutation
Drug (brand name)VX-661 (tezacaftor)
Drug administrationTablet taken by mouth
Eligible CF patientsAged 12 Years and Older, Homozygous for the F508del-CFTR mutation 
Controlled study?Yes (placebo controlled)
Randomised study?Yes
Blinded study?Yes (double blind - neither medical staff, nor participants knew which treatment participants were taking)
Extension study?No
Study timeframeThe study was conducted between January 2015 and January 2017


What does this mean for me?For people aged 12 years and above with two copies of the F508del mutation, the combination of VX-661 (tezacaftor) with ivacaftor improved lung function by about 4% in terms of FEV1% predicted, and did reduce the chance of getting a chest infection by about 35%. Safety appeared good. Overall this is a similar level of effectiveness as previously seen with Orkambi™ in people with two copies of F508del. Based on the press release, Vertex Pharmaceuticals now plan to apply to the United States Federal Drug Administration and European Medicines Agency to seek a license for this drug combination to be approved for this specific patient group and age range.
Study:This Phase 3 trial was conducted in over 90 trial sites in the USA and Europe.
Aim:To evaluate the efficacy and safety of VX-661 in combination with ivacaftor.
Participants:In total, over 500 patients were enrolled and randomly assigned to either the treatment group or the placebo group. 477 patients completed the study. There were 204 participants from 28 ECFS-CTN sites in Denmark, France, Germany, Italy, the Netherlands, Spain, Sweden, Switzerland and the UK.
Treatment:In the treatment group, patients received VX-661 100 mg plus ivacaftor 150 mg in the morning and ivacaftor 150 mg in the evening every day for 12 weeks. In the placebo group, patients received placebo pills in the morning and the evening every day for 24 weeks.
Safety:In general, treatment was generally well tolerated. The safety profile was similar between the VX-661/ivacaftor treatment group and the placebo group. The most common adverse events overall were infective pulmonary exacerbation, cough, headache, nasopharyngitis and sputum increased.
Efficacy:After 24 weeks of treatment, patients in the VX-661+ivacaftor group had 4% better lung function  than the placebo group, as measured by percent predicted forced expiratory volume in 1 second (ppFEV1). Patients in the treatment group also had significantly fewer pulmonary exacerbations.
Data source:The summary of data provided here is from a registry posting, available here: from a sponsor press release, available here: