Cystic Fibrosis (CF)PKCFNCT07629986
Pharmacokinetics of Antibiotics in Patients With Cystic Fibrosis Trated With Elexacaftor/Tezacaftor/Ivacaftor (ETI)
An observational study of Cystic Fibrosis (CF) and Pulmonary Exacerbation, run by Fondation Ildys at 1 site in France.
Trial summary
Cystic fibrosis (CF) is associated with major pharmacokinetic and pharmacodynamic alterations affecting antibiotic exposure, including changes in absorption, distribution, metabolism, and elimination. Read more about this study
- Who is it for?
- Ages 12 years and older
- Conditions the study is for
- Cystic Fibrosis (CF), Pulmonary Exacerbation, Respiratory Infection Bacterial
- How many people
- 30 participants
- Where
- 1 siteFrance
- Study dates
- 19 Mar 2026to May 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: CF patients
Who may be able to join
- 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
Who cannot join
- Lung transplantation or heart-lung transplantation
- Patients under guardianship or curatorship
- Pregnant or breastfeeding women
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Matthieu Pichelin contact
France1 site, 1 recruiting
- Recruiting
Fondation ILDYS
Roscoff, 29680
Marion Buyse, PharmD; PhD, 0298293447, marion.buyse@ildys.org
About this study
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.
Read more
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.
Read the detailed description
Patients with cystic fibrosis experience substantial physiological changes that affect the pharmacokinetics of medications, including antibiotics. Altered gastrointestinal absorption, increased volume of distribution, enhanced renal clearance, chronic systemic inflammation, and modified protein binding have historically led to recommendations for increased antibiotic dosing in CF patients.
Additionally, thick airway mucus, biofilm formation, high bacterial inoculum, and chronic airway infection contribute to altered antibiotic pharmacodynamics and reduced antibiotic efficacy.
Highly effective CFTR modulators, particularly elexacaftor/tezacaftor/ivacaftor (ETI), have profoundly changed the clinical course of cystic fibrosis by improving lung function, reducing pulmonary exacerbations, improving nutritional status, and modifying airway microbiology. These changes may normalize or partially normalize antibiotic pharmacokinetics and pharmacodynamics.
However, evidence regarding the impact of ETI therapy on antibiotic pharmacokinetics remains extremely limited. To date, only one retrospective pediatric study has evaluated the effect of CFTR modulators on intravenous tobramycin pharmacokinetics during pulmonary exacerbations.
The PKCF study aims to prospectively evaluate plasma antibiotic concentrations and pharmacokinetic parameters in CF patients receiving ETI during pulmonary exacerbations requiring antibiotic therapy. Antibiotic concentrations will be compared with established PK/PD targets according to current national recommendations.
The study may contribute to future optimization of antibiotic dosing strategies in patients with CF treated with ETI, while minimizing toxicity and supporting antimicrobial stewardship.
- Being tested
- No intervention assigned
- Keywords
- Cystic Fibrosis, CFTR modulators, Elexacaftor/Tezacaftor/Ivacaftor, Antibiotics, Pharmacokinetics, Therapeutic drug monitoring, Pulmonary Exacerbation
- Medical subject headings
- Cystic Fibrosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No intervention assignedOther
Routine antibiotic therapy and therapeutic drug monitoring are performed according to standard clinical practice
| Study group | Role | What they receive |
|---|---|---|
| Patients with cystic fibrosis treated with ETI receiving antibiotic therapy | Patients with cystic fibrosis treated with ETI receiving antibiotic therapy for pulmonary exacerbation Receives: Other: No intervention assigned |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pharmacokinetic profiles of antibiotics during pulmonary exacerbation treatment
Plasma antibiotic concentrations will be measured at Day 3 of treatment to determine pharmacokinetic parameters including:
- Cmax (maximum plasma concentration)
- Cmin (minimum plasma concentration)
Pharmacokinetic/pharmacodynamic ratios will be evaluated according to bacterial minimum inhibitory concentrations (MICs):
- Cmin/MIC ratio for time-dependent antibiotics
- Cmax/MIC ratio for concentration-dependent antibiotics Antibiotic exposure will be compared with PK/PD targets validated by national expert recommendations.
Measured: Day 3 of antibiotic therapy
Secondary outcomes (11)
Clinical efficacy: body weight evolution
the Clinical parameters body weight in kilograms
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: temperature evolution
the Clinical parameters temperature in celsius degree
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: appetite evolution
the Clinical parameters "appetite" will be score on a scale from 0 to 10 with higher score mean worse outcome
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: fatigue evolution
the Clinical parameters "fatigue" will be score on a scale from 0 to 10 with higher score mean worse outcome
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: dyspnea evolution
the Clinical parameters "dyspnea" will be score on a scale from 0 to 10 with higher score mean worse outcome
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: sputum volume
the Clinical parameters "sputum volume" will be score on a scale from 0 to 10 with higher score mean worse outcome
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: sputum purulence
the Clinical parameters "sputum purulence" will be score on a scale from 0 to 10 with higher score mean worse outcome
Measured: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
biological evolution: Renal function evolution
renal function will be evaluated by measuring plasma creatinine and calculated glomerular filtration rate
Measured: Baseline, Day 3, and end of antibiotic treatment
biological evolution: inflammatory markers
inflammation will be evaluated by measuring plasma c protein reactive and plasma leukocytes concentration
Measured: Baseline, Day 3, and end of antibiotic treatment
Treatment adherence
Treatment adherence will be evaluated by the ratio of antibiotic doses administered to doses prescribed
Measured: through study completion, an average 14 days
number of participants with treatment-related adverse events
Adverse events related to antibiotic therapy will be collected and graded according to NCI CTCAE version 6.0
Measured: through study completion, an average 14 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jun 2026
- Study start19 Mar 2026
- Primary completionMar 2028 (estimated)
- Study completionMay 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cystic Fibrosis (CF)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Fondation Ildys
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07629986
- Sponsor's protocol ID
- RI2025-016
- Other IDs
- 2025-A02333-46
- Acronym
- PKCF
- Status last verified
- Jun 2026
- First submitted
- 15 May 2026
- Last updated
- 5 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 5 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pharmacokinetics of Antibiotics in Patients With Cystic Fibrosis Trated With Elexacaftor/Tezacaftor/Ivacaftor (ETI)
- ClinicalTrials.gov ID
- NCT07629986
- Acronym / sponsor ID
- PKCF / RI2025-016
- Keywords
- Cystic Fibrosis, CFTR modulators, Elexacaftor/Tezacaftor/Ivacaftor, Antibiotics, Pharmacokinetics, Therapeutic drug monitoring, Pulmonary Exacerbation
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Fondation IldysUniversity, hospital or other
- Study start
- 19 Mar 2026 (actual)
- Primary completion
- Mar 2028 (estimated)
- Study completion
- May 2028 (estimated)
- First posted
- 5 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Patients with cystic fibrosis experience substantial physiological changes that affect the pharmacokinetics of medications, including antibiotics. Altered gastrointestinal absorption, increased volume of distribution, enhanced renal clearance, chronic systemic inflammation, and modified protein binding have historically led to recommendations for increased antibiotic dosing in CF patients.
Additionally, thick airway mucus, biofilm formation, high bacterial inoculum, and chronic airway infection contribute to altered antibiotic pharmacodynamics and reduced antibiotic efficacy.
Highly effective CFTR modulators, particularly elexacaftor/tezacaftor/ivacaftor (ETI), have profoundly changed the clinical course of cystic fibrosis by improving lung function, reducing pulmonary exacerbations, improving nutritional status, and modifying airway microbiology. These changes may normalize or partially normalize antibiotic pharmacokinetics and pharmacodynamics.
However, evidence regarding the impact of ETI therapy on antibiotic pharmacokinetics remains extremely limited. To date, only one retrospective pediatric study has evaluated the effect of CFTR modulators on intravenous tobramycin pharmacokinetics during pulmonary exacerbations.
The PKCF study aims to prospectively evaluate plasma antibiotic concentrations and pharmacokinetic parameters in CF patients receiving ETI during pulmonary exacerbations requiring antibiotic therapy. Antibiotic concentrations will be compared with established PK/PD targets according to current national recommendations.
The study may contribute to future optimization of antibiotic dosing strategies in patients with CF treated with ETI, while minimizing toxicity and supporting antimicrobial stewardship.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients with cystic fibrosis treated with ETI receiving antibiotic therapy | – | Other: No intervention assignedPatients with cystic fibrosis treated with ETI receiving antibiotic therapy for pulmonary exacerbation |
Who may qualify
- Ages
- 12 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- CF patients
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (3 listed)
- Lung transplantation or heart-lung transplantation
- Patients under guardianship or curatorship
- Pregnant or breastfeeding women
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No intervention assignedRoutine antibiotic therapy and therapeutic drug monitoring are performed according to standard clinical practice | Other | Patients with cystic fibrosis treated with ETI receiving antibiotic therapy |
Primary outcome
Pharmacokinetic profiles of antibiotics during pulmonary exacerbation treatment
Time frame: Day 3 of antibiotic therapy
Plasma antibiotic concentrations will be measured at Day 3 of treatment to determine pharmacokinetic parameters including: * Cmax (maximum plasma concentration) * Cmin (minimum plasma concentration) Pharmacokinetic/pharmacodynamic ratios will be evaluated according to bacterial minimum inhibitory concentrations (MICs): * Cmin/MIC ratio for time-dependent antibiotics * Cmax/MIC ratio for concentration-dependent antibiotics Antibiotic exposure will be compared with PK/PD targets validated by national expert recommendations.
11 secondary outcomes
Clinical efficacy: body weight evolution
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: temperature evolution
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: appetite evolution
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: fatigue evolution
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: dyspnea evolution
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: sputum volume
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
Clinical efficacy: sputum purulence
Time frame: Baseline, Day 3, Day 7-10, and end of antibiotic treatment
biological evolution: Renal function evolution
Time frame: Baseline, Day 3, and end of antibiotic treatment
biological evolution: inflammatory markers
Time frame: Baseline, Day 3, and end of antibiotic treatment
Treatment adherence
Time frame: through study completion, an average 14 days
number of participants with treatment-related adverse events
Time frame: through study completion, an average 14 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Jun 2026.
- Individual participant dataSharing planned: Undecided
Related trials for Cystic Fibrosis (CF)
Active, not recruiting
Personalized Mobile Health Platform to Promote Physical Activity in Adolescents and Young Adults With Cystic Fibrosis
Cystic Fibrosis (CF)
RecruitingObservational study
TIDES 2.0: Prevalence and Longitudinal Course of Depression, Anxiety, and Behavior Problems in Children With Cystic Fibrosis Under 12 Years of Age
Cystic Fibrosis (CF)
Active, not recruitingObservational study
Genetic Modifiers of Cystic Fibrosis (CF) Liver Disease
Cystic Fibrosis, Liver Disease
Recruiting
Long-term Evaluation of the SIMEOX Device at Home in Non-cystic Fibrosis Bronchiectasis
Non-cystic Fibrosis Bronchiectasis
RecruitingPhase 2
Phase 2 Study to Assess the Safety and Efficacy of ANG003
Exocrine Pancreatic Insufficiency (EPI), Cystic Fibrosis (CF)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Matthieu Pichelin contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cystic Fibrosis (CF) and Pulmonary Exacerbation, run by Fondation Ildys at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 5 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Marion Buyse, PharmD, PhD (+33298293447, marion.buyse@ildys.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pharmacokinetic profiles of antibiotics during pulmonary exacerbation treatment (time frame: Day 3 of antibiotic therapy). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jun 2026.