What the trial was testing
The trial enrolled 225 patients with cystic fibrosis. The study was sponsored by Vertex Pharmaceuticals and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was an early-stage trial — researchers are still confirming safety and getting an early look at how well the treatment works. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
Lung function jumped 13.8 percentage points in people with one hard-to-treat mutation.
New England Journal of Medicine · 2018 · NCT03227471
These findings — that improvement in lung function (FEV1) for people with one Phe508del and a minimal-function mutation — were published in the New England Journal of Medicine and represent the headline result of the study.
Researchers tracked outcomes across 225 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with cystic fibrosis, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Elexacaftor-tezacaftor-ivacaftor (Trikafta) is FDA-approved and available now for people 2 and older with cystic fibrosis who carry at least one Phe508del mutation — about 90% of patients. Most U.S. CF centers prescribe it as standard care. Ask your CF team if your specific mutation qualifies.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open cystic fibrosis trials
Cystic Fibrosis in the Kidney: Monitoring the Effectiveness of Elexacaftor/tezacaftor/ivacaftor in Urine After a Short Pause of Therapy
In cystic fibrosis (CF) renal base excretion is impaired, due to mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene, since CFTR function is crucial in regulation of the kidney's HCO3- excretion. The investigators suggest that challenged urine HCO3- excretion is a biomarker of CFTR function, which can be used to evaluate the extent of CFTR dysfunction and the possible correcting effects of CFTR modulating therapy. This study aims to evaluate changes in challenged urine HCO3- excretion in CF patients, who are currently in treatment with the triple CFTR modulator combination therapy, Elexacaftor/tezacaftor/ivacaftor (ETI), before, during, and after a short treatment pause.
Prevalence of Exercise-induced Ventilatory Limitation and Associated Factors in Patients With Cystic Fibrosis Receiving Elexacaftor-Tezacaftor-Ivacaftor
Cystic fibrosis is a genetic disorder affecting the entire body and associated with respiratory exacerbations, impaired quality of life and reduced life expectancy. The therapeutic management of cystic fibrosis has been profoundly changed by the recent arrival of a combination of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulators, Elexacaftor-Tezacaftor-Ivacaftor (ETI), which improve quality of life, respiratory function and reducing the number of exacerbations. The impact of these treatments on exercise adaptation has not been clearly identified. The main objective is to estimate the prevalence of ventilatory reserve amputation during submaximal exercise testing assessed by the 6-minute walk test (6MWT) in patients with cystic fibrosis treated with ETIs.