Association Between Chronic Kidney Disease Stage and Circulating FGF23 Cleavage Intensity in Patients With Chronic Kidney Disease (CLIFF)

June 24, 2026 updated by: Centre Hospitalier Universitaire de Saint Etienne
This cross-sectional proof-of-concept study aims to investigate the relationship between chronic kidney disease (CKD) severity and circulating FGF23 cleavage intensity estimated by the iFGF23/cFGF23 ratio. Eighty male patients aged 55-75 years with CKD stages 3a to 5 will be included (20 per stage). Blood samples obtained during routine nephrology care will be supplemented by two additional tubes to measure iFGF23, cFGF23, hepcidin, erythropoietin, 1,25-vitamin D and TRAP5b. The primary endpoint is the iFGF23/cFGF23 ratio. Secondary analyses will evaluate the associations between FGF23 forms and renal, hematological, iron metabolism and mineral bone parameters. This study will provide the first human data on FGF23 cleavage alterations across CKD stages and may identify novel biomarkers for anemia and cardiovascular complications.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

80

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • MRC stage 3a-5 based on the most recent GFR measurement
  • Patient enrolled in or eligible for a social security program
  • Patients who have received informed consent regarding the study and have given their verbal consent to participate

Exclusion Criteria:

  • Active cancer or a history of cancer in remission for less than 5 years, or a history of cancer in remission for more than 5 years with specific oncological treatment still ongoing.
  • Participation in another study related to treatments for the disease
  • Patients under legal guardianship (legal guardianship or conservatorship)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Patients CKD 3a
Patients with stage 3a kidney disease during a nephrology consultation with an investigator (inclusion visit).
Other: Blood sampling and biomarker assessment

Single study visit during routine nephrology follow-up. Routine blood analyses are performed as standard care. Two additional tubes (maximum 10 mL) are collected:

  • EDTA plasma tube for measurements of intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23), and hepcidin.
  • Serum tube for measurements of erythropoietin (EPO), 1,25-dihydroxyvitamin D, and TRAP5b.

Clinical and laboratory data collected include renal function parameters (eGFR, creatinine, urea, albuminuria), hematologic and iron metabolism markers (hemoglobin, ferritin, transferrin saturation, CRP), and bone-mineral metabolism markers (calcium, phosphate, PTH, vitamin D, bone alkaline phosphatase).
Active Comparator: Patients CKD 3b
Patients with stage 3b kidney disease during a nephrology consultation with an investigator (inclusion visit).
Other: Blood sampling and biomarker assessment

Single study visit during routine nephrology follow-up. Routine blood analyses are performed as standard care. Two additional tubes (maximum 10 mL) are collected:

  • EDTA plasma tube for measurements of intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23), and hepcidin.
  • Serum tube for measurements of erythropoietin (EPO), 1,25-dihydroxyvitamin D, and TRAP5b.

Clinical and laboratory data collected include renal function parameters (eGFR, creatinine, urea, albuminuria), hematologic and iron metabolism markers (hemoglobin, ferritin, transferrin saturation, CRP), and bone-mineral metabolism markers (calcium, phosphate, PTH, vitamin D, bone alkaline phosphatase).
Active Comparator: Patients CKD 4
Patients with stage 3b kidney disease during a nephrology consultation with an investigator (inclusion visit).
Other: Blood sampling and biomarker assessment

Single study visit during routine nephrology follow-up. Routine blood analyses are performed as standard care. Two additional tubes (maximum 10 mL) are collected:

  • EDTA plasma tube for measurements of intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23), and hepcidin.
  • Serum tube for measurements of erythropoietin (EPO), 1,25-dihydroxyvitamin D, and TRAP5b.

Clinical and laboratory data collected include renal function parameters (eGFR, creatinine, urea, albuminuria), hematologic and iron metabolism markers (hemoglobin, ferritin, transferrin saturation, CRP), and bone-mineral metabolism markers (calcium, phosphate, PTH, vitamin D, bone alkaline phosphatase).
Active Comparator: Patients CKD 5
Patients with stage 5 kidney disease during a nephrology consultation with an investigator (inclusion visit).
Other: Blood sampling and biomarker assessment

Single study visit during routine nephrology follow-up. Routine blood analyses are performed as standard care. Two additional tubes (maximum 10 mL) are collected:

  • EDTA plasma tube for measurements of intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23), and hepcidin.
  • Serum tube for measurements of erythropoietin (EPO), 1,25-dihydroxyvitamin D, and TRAP5b.

Clinical and laboratory data collected include renal function parameters (eGFR, creatinine, urea, albuminuria), hematologic and iron metabolism markers (hemoglobin, ferritin, transferrin saturation, CRP), and bone-mineral metabolism markers (calcium, phosphate, PTH, vitamin D, bone alkaline phosphatase).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evaluate the association between CKD stages and the intensity of circulating FGF23 cleavage in CKD patients.
Time Frame: At inclusion
The intensity of FGF23 cleavage will be estimated using the iFGF23/cFGF23 ratio and compared across CKD stages 3a to 5.
At inclusion

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Plasma concentrations of iFGF23 and cFGF23
Time Frame: At inclusion
Evaluation of changes in circulating intact FGF23 and C-terminal FGF23 concentrations according to CKD stage.
At inclusion
Association between FGF23 cleavage intensity and anemia-related parameters
Time Frame: At inclusion
Assessment of associations between iFGF23/cFGF23 ratio and hemoglobin, ferritin, transferrin saturation, CRP, hepcidin and erythropoietin independently of CKD stage.
At inclusion
Association between FGF23 concentrations and renal parameters
Time Frame: At inclusion
Assessment of associations between iFGF23 and cFGF23 concentrations and eGFR, creatinine and albuminuria using correlation and multivariable analyses.
At inclusion
Association between FGF23 concentrations and mineral-bone metabolism markers
Time Frame: At inclusion
Assessment of associations between iFGF23 and cFGF23 concentrations and phosphate, calcium, PTH, vitamin D, bone alkaline phosphatase and TRAP5b.
At inclusion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Centre Hospitalier Universitaire de Saint Etienne

Investigators

  • Principal Investigator: Christophe MARIAT, PHD, CHUSE

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

June 24, 2026

First Submitted That Met QC Criteria

June 24, 2026

First Posted (Actual)

June 30, 2026

Study Record Updates

Last Update Posted (Actual)

June 30, 2026

Last Update Submitted That Met QC Criteria

June 24, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25CH338
  • ANSM (Other Identifier: 2021-A02121-40)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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