stella
Cystic FibrosisDecember 2024Summary reviewed May 2026

Trikafta Improved Lung Function in Cystic Fibrosis Patients with Rare N1303K Mutation

This 20-patient trial tested whether elexacaftor-tezacaftor-ivacaftor (Trikafta) helps people with the rare N1303K cystic fibrosis mutation, who have not been approved for the drug. Lung function and weight improved, but the sweat chloride test did not.

What the trial was testing

The trial enrolled 42 patients with cystic fibrosis. The study was sponsored by Emory University and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was initial testing (phase 2). 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

9.5 percentage point lung function gain in N1303K patients on Trikafta.

The Lancet Respiratory Medicine · 2024 · NCT03506061

These findings — that improvement in lung function (FEV1) on Trikafta in CF with the N1303K mutation — were published in the The Lancet Respiratory Medicine and represent the headline result of the study.

Researchers tracked outcomes across 42 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

Trikafta is FDA-approved for many CF mutations but not officially for N1303K. This trial supports off-label use, and the U.S. Cystic Fibrosis Foundation supports trying Trikafta for N1303K based on real-world response. Ask your CF team to discuss with insurance.

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

RecruitingInterventional study

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.

Aarhus C, Central Jutland, Denmark
RecruitingInterventional study

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.

Lille, France