How antibiotics behave in people with cystic fibrosis on ETI therapy
Measures antibiotic levels during lung flare-ups in people with cystic fibrosis.
Plain-language title generated from the registry record
Registry title: Pharmacokinetics of Antibiotics in Patients With Cystic Fibrosis Trated With Elexacaftor/Tezacaftor/Ivacaftor (ETI)
Key facts
- Where
- Roscoff, FranceSee the site
Where in France
- Fondation ILDYSRoscoff, FranceTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Fondation Ildys
- Trial code
- NCT07629986
- Record updated
- 5 June 2026
- Original description
Cystic fibrosis (CF) is associated with major pharmacokinetic and pharmacodynamic alterations affecting antibiotic exposure, including changes in absorption, distribution, metabolism, and elimination. Historically, these alterations justified the use of higher antibiotic doses in CF patients in order to achieve therapeutic concentrations and improve pulmonary outcomes.Read full original descriptionShow less
Pharmacokinetics of Antibiotics in Patients With Cystic Fibrosis Trated With Elexacaftor/Tezacaftor/Ivacaftor (ETI)
Cystic fibrosis (CF) is associated with major pharmacokinetic and pharmacodynamic alterations affecting antibiotic exposure, including changes in absorption, distribution, metabolism, and elimination. Historically, these alterations justified the use of higher antibiotic doses in CF patients in order to achieve therapeutic concentrations and improve pulmonary outcomes.
The advent of highly effective CFTR modulators, particularly the triple combination elexacaftor/tezacaftor/ivacaftor (ETI), has substantially improved pulmonary function, nutritional status, inflammatory burden, and quality of life in patients with CF. ETI therapy also appears to modify respiratory microbiology and reduce the frequency of pulmonary exacerbations.
These clinical and physiological improvements may alter antibiotic pharmacokinetics and pharmacodynamics in patients with CF, potentially making current high-dose antibiotic recommendations less appropriate for some patients. Since repeated exposure to high-dose antibiotics is associated with cumulative toxicities, particularly aminoglycoside-related ototoxicity and nephrotoxicity, reassessment of antibiotic dosing strategies is warranted.
The PKCF study is a multicenter, prospective, observational, non-interventional study designed to characterize the pharmacokinetic profiles of intravenous antibiotics administered during pulmonary exacerbations in adolescents and adults with cystic fibrosis receiving ETI therapy.
Inclusion: Diagnosis of cystic fibrosis confirmed by sweat test and/or genetic testing; Treatment with elexacaftor/tezacaftor/ivacaftor (ETI) for at least 3 months; Age 12 years or older; Patient informed and not objecting to participation; for minors, parents/legal guardians informed and not objecting to participation; Clinical indication for antibiotic therapy for pulmonary exacerbation or respiratory infection according to treating physician; Affiliation to a social security system.
Exclusion: Lung transplantation or heart-lung transplantation; Patients under guardianship or curatorship; Pregnant or breastfeeding women.