A Phase 3 interventional study of ELX/TEZ/IVA and IVA in Cystic Fibrosis, sponsored by Vertex Pharmaceuticals Incorporated. Completed at 19 sites in 7 countries. Open to participants aged 12 Months to 24 Months. Per ClinicalTrials.gov, last updated 2025-10-06.
Sponsored by Vertex Pharmaceuticals Incorporated · Phase 3, Interventional, and Treatment
This study will evaluate the pharmacokinetics (PK), safety, tolerability, pharmacodynamics (PD), and efficacy of ELX/TEZ/IVA in CF subjects 12 to less than (\<) 24 months of age.
1,581 studies on the registry are indexed under Cystic Fibrosis; 190 are open to participants now.
This study's enrollment of 70 is above the median of 36 across 1,034 interventional studies indexed under Cystic Fibrosis.
Browse Cystic Fibrosis studies →Vertex Pharmaceuticals Incorporated is the lead sponsor of 243 studies on the registry; 19 are open to participants now.
Of its 102 completed or terminated interventional studies of FDA-regulated products, 49 (48%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Participants who have at least 1 F508del mutation in the CF transmembrane conductance regulator (CFTR) gene or another ELX/TEZ/IVA-responsive CFTR mutation
Key Exclusion Criteria:
History of any illness or any clinical condition that, in the opinion of the investigator, might either confound the results of the study or pose an additional risk in administering study drug(s) to the participant
Other protocol defined Inclusion/Exclusion criteria may apply.
Participants will receive ELX/TEZ/IVA in the morning and IVA in the evening.
Drug: ELX/TEZ/IVA · Drug: IVA
Participants will receive ELX/TEZ/IVA in the morning and IVA in the evening with the dose(s) to be based on the outcome of Part A.
Drug: ELX/TEZ/IVA · Drug: IVA
Fixed-dose combination granules for oral administration.
Also known as: VX-445/VX-661/VX-770, elexacaftor/tezacaftor/ivacaftor
Granules for oral administration
Also known as: VX-770, ivacaftor
Part A: Observed Pre-dose Concentration (Ctrough) of ELX, TEZ, IVA, and their Relevant Metabolites
Time frame: Day 1 up to Day 15
Part A: Safety and Tolerability as Assessed by Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time frame: Day 1 up to Day 43
Part B: Safety and Tolerability as Assessed by Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time frame: Day 1 up to Week 28
Part B: Observed Pre-dose Concentration (Ctrough) of ELX, TEZ, IVA, and their Relevant Metabolites
Time frame: Day 15 up to Week 16
Part B: Absolute Change in Sweat Chloride (SwCl)
Time frame: From Baseline Through Week 24
Plan to share: No — Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/independent-research/clinical-trial-data-sharing
No publications or documents are linked to this record.
This study is completed, as verified in Oct 2025. You cannot join it, but the record below documents what was studied.
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Vertex Pharmaceuticals Incorporated