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Clinical trials identifierNCT01531673
Study codesVX-661-101
Study titleStudy of VX-661 Alone and in Combination With Ivacaftor in Subjects Homozygous or Heterozygous to the F508del-Cystic Fibrosis Transmembrane Conductance Regulator(CFTR) Mutation
SponsorVertex
Drug (brand name)Tezacaftor (VX-661) and Ivacaftor
Drug administrationTablet
Eligible CF patientsAged at least 12 years
Controlled study?Yes
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 February 2012 and March 2014




Study:This Phase 2 study was conducted in 36 sites across 4 countries.
Aim:This study assessed the safety and efficacy of tezacaftor alone and in combination with ivacaftor.
In Part A, people with two copies of the F508del CFTR mutation were randomised to receive either placebo, tezacaftor alone (one of 4 doses) or tezacaftor in combination with ivacaftor.
In Part B people who were already taking ivacaftor and who have one copy of F508del CFTR mutation and one copy of the G551D CFTR mutation were enrolled. This group was randomized to receive either placebo or tezacaftor alone.
Participants:146 participants were enrolled (128 in Part A and 18 in Part B).
Treatment:

In Part A, patients were treated for 28 days in the following groups:
•    Tezacaftor alone 10 mg once daily
•    Tezacaftor alone 30 mg once daily
•    Tezacaftor alone 100 mg once daily
•    Tezacaftor alone 150 mg once daily
•    Tezacaftor 10 mg once daily plus ivacaftor 150 mg twice daily
•    Tezacaftor 30 mg once daily plus ivacaftor 150 mg twice daily
•    Tezacaftor 100 mg once daily plus ivacaftor 150 mg twice daily
•    Tezacaftor 150 mg once daily plus ivacaftor 150 mg twice daily
•    Tezacaftor 100 mg once daily plus ivacaftor 50 mg twice daily
•    Tezacaftor 50 mg twice daily plus ivacaftor 150 mg twice daily
Each treatment group had a corresponding placebo group where patients were treated with dummy sugar pills designed to look exactly like the test medication.

In Part B, patients were treated for 28 days in the following groups:
•    Tezacaftor alone 100 mg once daily
•    Placebo 

Safety:    Tezacaftor was generally well tolerated. 
Side effects occurred similarly in all the treatment groups.
Efficacy:After 28 days of treatment with tezacaftor 100 mg once daily/ivacaftor 150 mg twice daily, sweat chloride and lung function (measured by FEV1 % predicted) improved significantly in people with 2 copies of the F508del CFTR mutation and in people with one copy of F508del CFTR mutation and one copy of the G551D CFTR mutation.
Data source:The summary of data provided here is from a peer-reviewed publication, available here: https://www.ncbi.nlm.nih.gov/pubmed/28930490 and from clinicaltrials.gov.

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