AzTrials
AzTrials

Hyperphosphatemia Related to Chronic Kidney DiseasePhase 3NCT04523727

Study to Evaluate the Safety and Tolerability of Ferric Citrate in Children With Hyperphosphatemia Related to Chronic Kidney Disease

A Phase 3 study testing ferric citrate in people with Hyperphosphatemia Related to Chronic Kidney Disease, run by Keryx Biopharmaceuticals at 14 sites in United States.

Suspended

Paused. Enrolment is on hold for now and may resume.

Official record
Search all trials

Trial summary

This study will be conducted to assess the safety and tolerability of ferric citrate in pediatric participants with hyperphosphatemia related to chronic kidney disease (CKD). Read more about this study

Who is it for?
Ages 6 to 16 years
What is being tested?
ferric citrate
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
45 participants
Where
14 sitesUnited States
Study dates
16 Jun 2022to Oct 2027
Phase
Phase 3
Are there results?
None posted in the registry

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 6 to 16 years
  • All sexes
  • No healthy volunteers
  • Child

Who may be able to join

  • Age 6 years to <17 years at Screening.
  • Weight ≥ 20 kilograms (kg) (dry weight for dialysis participants) at Screening.
  • Chronic kidney disease (CKD) requiring chronic dialysis (i.e., hemodialysis or peritoneal dialysis), or CKD not on dialysis with an estimated glomerular filtration rate (eGFR) <30 milliliters per minute (mL/min)/1.73 meters squared (m^2) at Screening.
  • Documented history of CKD-related hyperphosphatemia for at least 3 months prior to the screening visit.
  • If participant is or is not on phosphate binder(s) at Visit 1, serum phosphorus must be:
  • 6 to <13 years: >5.8 milligrams per deciliter (mg/dL).
Show all 15Show fewer
  • 13 to <17 years: >4.5 mg/dL.
  • If participant is on phosphate binder(s) at Visit 1, and serum phosphorus is not greater than the above stated age-limit criteria, approximately 1 to 4-weeks of washout period is required and at Visit 1a or Visit 1b, serum phosphorus must be greater than the age above stated age-limit criteria.
  • Transferrin saturation (TSAT) <50%.
  • Serum ferritin of <650 nanograms per milliliter (ng/mL).
  • Parent/legal guardian must be willing and able to give written informed consent, and child (participant) willing and able to give age-appropriate assent according to local regulatory requirements.
  • Female participants of childbearing potential, defined as post menarche and not surgically sterile, must have a negative serum pregnancy test.
  • Dialysis adequacy stable on current mode of dialysis prior to screening and agree to maintain dialysis prescription for the duration of the pharmacodynamic assessment period unless changes are needed for safety. A minimum dialysis adequacy (dialysis clearance of urea-dialysis time/volume of distribution of urea [Kt/V]), defined by the following:
  • Hemodialysis adequacy: single-pool Kt/V ≥1.2 for at least 1 hemodialysis session within 2 months.
  • Peritoneal dialysis: At least 1Kt/V reading ≥1.8 within 4 months.

Who cannot join

  • Active significant GI disorder, including overt GI bleeding or active inflammatory bowel disease.
  • Liver transaminases (aspartate aminotransferase [AST] or alanine aminotransferase [ALT]) >3× the upper limit of normal at Screening.
  • Unable to swallow pills, if participant requires tube feeding, ferric citrate must be taken orally and not administered via feeding tube.
  • Non-renal cause of hyperphosphatemia.
  • Active drug or alcohol dependence or abuse (excluding tobacco use or medicinal marijuana) within the 12 months prior to Screening or evidence of such abuse (in the opinion of the Investigator).
  • Malignancy, except for participants who have been disease-free for at least 2 years after curative therapy.
Show all 17Show fewer
  • Participants with a functioning organ transplant.
  • A known allergy or intolerance to ferric citrate or any of its constituents.
  • Female participants who do not agree to remain abstinent or assent to use a combination of 2 of the following highly effective birth control methods for at least 28 days before the first dose, during the study (including during dose interruptions), and for at least 30 days after the last dose:
  • Barrier method of contraception: condoms (female or male) with or without a spermicidal agent, diaphragm, or cervical cap with spermicide.
  • Intrauterine device (IUD).
  • Hormone-based contraceptives which are associated with inhibition of ovulation.
  • Females who are pregnant or breast-feeding other children. Participants who are being breastfed are eligible to participate in this study.
  • Any other medical condition that, in the opinion of the Investigator, renders the participant unable to or unlikely to complete the trial or that would interfere with optimal participation in the trial or produce significant risk to the participant.
  • The participant, in the opinion of the Investigator, is unable to adhere to the requirements of the study.
  • Receipt of any investigational drug within 4 weeks before Screening.
  • History of hemochromatosis or iron overload syndrome (e.g, hereditary sideroblastic anemia, thalassemia).

Trial locations and contacts

14 sites in 1 country.

14 sites in 1 country

United States14 sites

  • University of New Mexico

    Albuquerque, New Mexico, 87110

  • Children's Hospital Colorado

    Aurora, Colorado, 80045

  • Johns Hopkins Hospital

    Baltimore, Maryland, 21287

  • University of Alabama at Birmingham (UAB) - Children's of Alabama

    Birmingham, Alabama, 35233

  • Cincinnati Children's Hospital Medical Center

    Cincinnati, Ohio, 45229

  • Helen DeVos Children's Hospital at Spectrum Health

    Grand Rapids, Michigan, 49503

  • Children's Mercy Hospital - Kansas City

    Kansas City, Missouri, 64108

  • University of Minnesota

    Minneapolis, Minnesota, 55455

  • Phoenix Childrens Hospital

    Phoenix, Arizona, 85016

  • University of Utah

    Salt Lake City, Utah, 84113

  • University of California, San Francisco (UCSF) - Department of Nephrology

    San Francisco, California, 94158

  • Seattle Children's Hospital

    Seattle, Washington, 98105

  • Stanford University Medical Center

    Stanford, California, 94305

  • University of South Florida

    Tampa, Florida, 33606

Other trials in United States

About this study

Official title: A 36-week, Single-Arm, Open-label Study to Evaluate the Safety and Tolerability of Ferric Citrate in Children With Hyperphosphatemia Related to Chronic Kidney Disease

This study will be conducted to assess the safety and tolerability of ferric citrate in pediatric participants with hyperphosphatemia related to chronic kidney disease (CKD).

Being tested
ferric citrate
Keywords
hyperphosphatemia, chronic kidney disease, CKD, ferric citrate, pediatric, dialysis
Medical subject headings
Hyperphosphatemia, Renal Insufficiency, Chronic

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • ferric citrateDrug

    Also called KRX-0502

    oral tablets

Study groups in NCT04523727
Study groupRoleWhat they receive
Ferric citrateExperimentalParticipants aged 6 to < 17 years will receive ferric citrate for 36 weeks at a starting dose based on body weight categories.
Receives: Drug: ferric citrate

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of participants with serious and non-serious treatment-emergent adverse events (TEAEs) including gastrointestinal (GI) AEs of special interest

    Measured: up to Week 40

  2. Number of participants with clinically significant laboratory abnormalities or changes in laboratory results

    Measured: up to Week 40

  3. Number of participants with TEAEs leading to the discontinuation of ferric citrate

    Measured: up to Week 40

Secondary outcomes (1)

  1. Change from baseline in serum phosphorus to Week 12/early termination (ET)

    Measured: Baseline; up to Week 12

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Aug 2020
  2. Study start16 Jun 2022
  3. Primary completionDec 2026 (estimated)
  4. Study completionOct 2027 (estimated)

Why it stopped: Sponsor decision

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
45 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04523727
Sponsor's protocol ID
KRX-0502-308
Status last verified
Jun 2026
First submitted
19 Aug 2020
Last updated
22 Jun 2026
Results posted
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing ferric citrate in people with Hyperphosphatemia Related to Chronic Kidney Disease, run by Keryx Biopharmaceuticals at 14 sites in United States.

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 15 inclusion and 17 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: paused, as of the sponsor's last update on 22 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 14 sites in United States. 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.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Results are not available in the source record.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of participants with serious and non-serious treatment-emergent adverse events (TEAEs) including gastrointestinal (GI) AEs of special interest (time frame: up to Week 40). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04523727.

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 22 Jun 2026.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in