Phase 3 Cystic Fibrosis Trial, Completed NCT04353817 Sponsor: Vertex Pharmaceuticals Incorporated Condition: Cystic Fibrosis
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Trial results

AI generated results summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI

According to the results reported on ClinicalTrials.gov, this trial (NCT04353817) enrolled 121 people with cystic fibrosis — 61 received a placebo (an inactive treatment) and 60 received a combination medicine called ELX/TEZ/IVA. The trial was measuring changes in two things: a lung function test called the Lung Clearance Index (LCI2.5), which measures how evenly air moves in and out of the lungs (a lower score generally means more even airflow, with 7.5 or below considered normal), and sweat chloride levels, which reflect how a protein linked to cystic fibrosis is working in the body. The reported data shows that, on average, the LCI2.5 score changed by −0.02 in the placebo group and −2.29 in the ELX/TEZ/IVA group over the course of the study — meaning the ELX/TEZ/IVA group's scores moved further in the downward direction. For sweat chloride levels, the placebo group saw an average change of −0.9 mmol/L (millimoles per litre), while the ELX/TEZ/IVA group saw an average change of −52.1 mmol/L. These are the numbers as submitted; the trial did not report whether these differences met any pre-set statistical threshold in the data provided here. The reported data also includes information on unwanted health events that occurred during the trial. In the placebo group, 57 out of 61 participants experienced at least one treatment-emergent adverse event (an unwanted health event that occurred after starting the study treatment), compared with 48 out of 60 in the ELX/TEZ/IVA group. Serious adverse events — more significant health events — were reported in 9 participants in the placebo group and 4 in the ELX/TEZ/IVA group. These figures describe what was recorded and counted; they do not on their own indicate whether any treatment is safer or riskier than another. These are the results as reported to ClinicalTrials.gov. They are not medical advice — always discuss what they mean for you with your doctor.

These are the results as reported to ClinicalTrials.gov, not medical advice. Verify independently with the trial site and discuss what they mean for you with your doctor.

Phase 3 Cystic Fibrosis Trial, Completed

NCT04353817
Completed Phase 3 🇦🇺 Australian site

Who may be able to join

AI generated eligibility summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI

Who might be able to join this trial:

  • You carry one copy of a specific gene change called F508del (meaning you have one F508del mutation and one other type of mutation) (confirm with trial site)
  • Your lung function test result (measuring how much air you can breathe out in one second) is 70% or above of the expected level

Who may not be able to join:

  • You have significant scarring of the liver (cirrhosis), with or without increased blood pressure in the liver's blood vessels
  • You have a lung infection caused by certain germs that are known to cause lung health to get worse more quickly (confirm with trial site)
  • You have previously had a transplant of a solid organ (such as a kidney, liver, or lung) or of blood/bone marrow cells

Important: There may be additional requirements not listed here. Always verify eligibility with the trial site directly before applying.

Based on publicly available eligibility criteria from ClinicalTrials.gov. Verify directly with the trial site before acting. This is not medical advice.

This is a simplified plain English summary of the eligibility criteria. Full criteria are set by the trial investigators and may include additional requirements not shown here. Never self-exclude from a trial based on this summary. Contact the trial site directly to confirm your eligibility.
Last synced 28 July 2026
Phase 3: approximately ~65% of drugs entering this phase reach regulatory approval, based on published industry-wide historical data. This is not specific to this trial.
Phase success rates shown are historical industry-wide averages based on published data. They are not a prediction for this specific trial or your individual situation.

Contact this trial

Australian sites

Telethon Kids Institute, Nedlands,
Queensland Children's Hospital, South Brisbane,
The Children's Hospital at Westmead, Westmead,

Contact details sourced from ClinicalTrials.gov. Verify directly with the trial site before attending.

GP referral letter

Print a one-page summary to share with your doctor.

Trial details

Status
Completed
Phase
Phase 3
Registry
ClinicalTrials.gov
Start date
19 June 2020
Est. completion
17 May 2021

Where this trial is recruiting

🇦🇺 Australia 🇨🇦 Canada 🇩🇰 Denmark 🇫🇷 France 🇩🇪 Germany 🇮🇱 Israel 🇳🇱 Netherlands 🇪🇸 Spain 🇨🇭 Switzerland 🇬🇧 United Kingdom

3 site(s) in Australia. Confirm current status and contact details directly with the trial site.

Primary endpoints

Absolute Change in Lung Clearance Index 2.5 (LCI2.5)

Can't join this trial?

Expanded access pathways

If this trial is not available to you, other access pathways may exist. In Australia, the TGA Special Access Scheme allows access to unapproved therapeutic goods for individual patients.

TGA Special Access Scheme information

Find other recruiting trials on ClinicalTrials.gov

Data last synced from ClinicalTrials.gov: 28 July 2026. Trial status can change. Always verify current status directly with the trial site before making any decision.

Trial recruitment status can change without notice between our nightly data updates. Always contact the trial site directly to confirm current recruitment status before making any decisions or travel arrangements.

View original record on ClinicalTrials.gov