Iron DeficiencyPhase 2NCT01736397

Ferric Citrate in Managing Serum Phosphorus and Iron Deficiency in Anemic Chronic Kidney Disease (CKD) Subjects Not on Dialysis

A Phase 2 study testing Ferric Citrate in people with Iron Deficiency and Iron Deficiency Anemia, run by Keryx Biopharmaceuticals at 20 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The purpose of this study is to determine if KRX-0502 (ferric citrate) is a safe and effective treatment for the management of serum phosphorus levels and iron deficiency in anemic chronic kidney disease (CKD) stage 3-5 subjects not on dialysis. Total length of treatment is approximately 12 weeks. Read more about this study

Who is it for?: Ages 18 years and older
Conditions the study is for: Iron Deficiency, Iron Deficiency Anemia
What is being tested?: Ferric Citrate
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 149 participants
Where: 20 sitesUnited States
Study dates: Nov 2012to Dec 2013
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 18 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Stage III to V Chronic Kidney Disease
Serum Phosphorus 4.0-6.0 mg/dL prior to Randomization
Ferritin 300 ng/mL or less
Transferrin Saturation (TSAT) 30% or less
Hemoglobin >9.0 and <12.0 g/dL
Must consume a minimum of 2 meals per day

Who cannot join

Parathyroidectomy within 24 weeks of study
gastrointestinal bleed or inflammatory bowel disease within 12 weeks of study
Requirement for dialysis or kidney injury within 8 weeks of study
Absolute requirement for oral iron, intravenous iron, Erythropoiesis-Stimulating Agent, blood transfusions, and Sensipar during the study
Absolute requirement for calcium-, magnesium-, or aluminum-containing drugs with meals
Absolute requirement for vitamin C, niacin, or nicotinamide outside of multivitamins

Show all 9Show fewer

History of hemochromatosis
Allergy to iron products
History of malignancy in last 5 years

Trial locations and contacts

20 sites in 1 country.

City, postcode or hospital

20 sites in 1 country

United States20 sites

Study site
Asheville, North Carolina
Study site
Bethesda, Maryland
Study site
Denver, Colorado
Study site
Detroit, Michigan
Study site
Edgewater, Florida
Study site
Evergreen Park, Illinois
Study site
Great Neck, New York
Study site
Houston, Texas
Study site
La Mesa, California
Study site
Meridian, Idaho
Study site
Miami, Florida
Study site
Mineola, New York
Study site
Orangeburg, South Carolina
Study site
Pontiac, Michigan
Study site
Reno, Nevada
Study site
Sacramento, California
Study site
San Antonio, Texas
Study site
Springfield, Massachusetts
Study site
Tempe, Arizona
Study site
Wilmington, North Carolina

Other trials in United States

About this study

Official title: A Phase 2 Study of KRX-0502 (Ferric Citrate) in Managing Serum Phosphorus and Iron Deficiency in Anemic Subjects With Stage III to V Chronic Kidney Disease Not on Dialysis

Read the detailed description

This is a randomized, double-blind, placebo-controlled, three-period, multi-center clinical trial. Following a Screening and Qualification Period and a two-week Washout Period (for those subjects entering the study on a phosphate binder), eligible subjects will be randomized in a 1:1 ratio to receive either KRX-0502 (ferric citrate) or placebo for up to approximately 12 weeks. The purpose of this study is to determine if KRX-0502 (ferric citrate) is a safe and effective treatment for the management of serum phosphorus levels and iron deficiency in anemic CKD subjects not on dialysis.

Conditions: Iron Deficiency, Iron Deficiency Anemia
Being tested: Ferric Citrate, Placebo
Keywords: CKD, Chronic Kidney Disease, Phosphorus, Iron Deficiency, Iron Deficiency Anemia, Elevated Phosphorus
Medical subject headings: Iron Deficiencies, Anemia, Iron-Deficiency, 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
Dose depends on serum phosphorus levels collected at each study visit.
PlaceboDrug

Study groups in NCT01736397
Study group	Role	What they receive
Ferric Citrate	Experimental	Ferric citrate will be taken with or within one hour of meals or snacks. The starting dose of ferric citrate is 3 tablets/day and titrated by the subject's serum phosphorus results at each treatment visit. Receives: Drug: Ferric Citrate
Placebo	Placebo comparator	Placebo will be taken with or within one hour of meals or snacks. The starting dose of placebo is 3 tablets per day and titrated by the subject's serum phosphorus results at each treatment visit. Receives: Drug: Placebo

What is being measured

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

Change in Transferrin Saturation (TSAT) From Baseline to End of Treatment
The difference in TSAT between the value at the end of treatment (week 12) minus the baseline measurement.
Measured: 12 Weeks
Change in Serum Phosphorus Levels From Baseline to End of Treatment
The difference in serum phosphorus between the value at the end of treatment (week 12) minus the baseline measurement.
Measured: 12 Weeks

Secondary outcomes (2)

Change in Ferritin Levels From Baseline to End of Treatment
The difference in ferritin levels between the value at the end of treatment (week 12) minus the baseline measurement.
Measured: 12 Weeks
Change in Hemoglobin Levels From Baseline to End of Treatment
The difference in hemoglobin levels between the value at the end of treatment (week 12) minus the baseline measurement.
Measured: 12 Weeks

Timeline

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

Nov 2012Dec 2013

First posted29 Nov 2012 (estimated)
Study startNov 2012
Primary completionNov 2013
Study completionDec 2013

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (2)Papers the sponsor has linked to this study.
Other trials for Iron DeficiencyStudies 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: Interventional
Phase: Phase 2
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind
Who is masked: Participant, Investigator
Enrolment: 149 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT01736397
Sponsor's protocol ID: KRX-0502-204
Status last verified: Sep 2017
First submitted: 16 Nov 2012
Last updated: 20 Oct 2017
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes

Publications

Natale P, Green SC, Ruospo M, Craig JC, Vecchio M, Elder GJ, Strippoli GF. Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD). Cochrane Database Syst Rev. 2025 Jun 27;6(6):CD006023. doi: 10.1002/14651858.CD006023.pub4.
PubMed 40576086
Block GA, Fishbane S, Rodriguez M, Smits G, Shemesh S, Pergola PE, Wolf M, Chertow GM. A 12-week, double-blind, placebo-controlled trial of ferric citrate for the treatment of iron deficiency anemia and reduction of serum phosphate in patients with CKD Stages 3-5. Am J Kidney Dis. 2015 May;65(5):728-36. doi: 10.1053/j.ajkd.2014.10.014. Epub 2014 Nov 4.
PubMed 25468387

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

RecruitingPhase 4
The Effects of Ferric Derisomaltose in Patients With Acute Heart Failure and Iron Deficiency on Exercise Capacity and Quality of Life(COREVIVE-HFrEF)
Heart Failure With Reduced Ejection Fraction, Iron Deficiency
Recruiting
Iron Absorption From a Nutritional Iron Supplement
Iron Absorption, Iron Deficiencies
RecruitingPhase 4
The Effects of Ferric Derisomaltose in Patients With Acute Heart Failure and Iron Deficiency on Exercise Capacity and Quality of Life
Heart Failure With Preserved Ejection Fraction, Iron Deficiencies
Recruiting
The Effects of Iron Treatment on Vaccine Immunogenicity in Kenyan Infants With Iron Deficiency
Iron Deficiencies
RecruitingPhase 4
The Effects of Low-Dose Versus High-Dose Intravenous IRON Therapy With Ferric DerisomaltOSE in Patients With Chronic Heart Failure and Iron Deficiency
Heart Failure, Iron Deficiency

All Iron Deficiency trials

Study at a glance

From the registry record, last updated by the sponsor on 20 Oct 2017. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase 2 Study of KRX-0502 (Ferric Citrate) in Managing Serum Phosphorus and Iron Deficiency in Anemic Subjects With Stage III to V Chronic Kidney Disease Not on Dialysis
ClinicalTrials.gov ID: NCT01736397
Acronym / sponsor ID: KRX-0502-204
Conditions: Iron Deficiency, Iron Deficiency Anemia
Keywords: CKD, Chronic Kidney Disease, Phosphorus, Iron Deficiency, Iron Deficiency Anemia, Elevated Phosphorus
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 149 participants (actual)
Lead sponsor: Keryx BiopharmaceuticalsIndustry (pharma, biotech, devices)
Study start: Nov 2012
Primary completion: Nov 2013 (actual)
Study completion: Dec 2013 (actual)
First posted: 29 Nov 2012 (estimated)
Results: Posted 20 Oct 2017

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind (participant, investigator)
Number of arms: 2

Arm	Type	Receives
Ferric Citrate	Experimental	Drug: Ferric CitrateFerric citrate will be taken with or within one hour of meals or snacks. The starting dose of ferric citrate is 3 tablets/day and titrated by the subject's serum phosphorus results at each treatment visit.
Placebo	Placebo comparator	Drug: PlaceboPlacebo will be taken with or within one hour of meals or snacks. The starting dose of placebo is 3 tablets per day and titrated by the subject's serum phosphorus results at each treatment visit.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (6 listed)

Stage III to V Chronic Kidney Disease
Serum Phosphorus 4.0-6.0 mg/dL prior to Randomization
Ferritin 300 ng/mL or less
Transferrin Saturation (TSAT) 30% or less
Hemoglobin >9.0 and <12.0 g/dL

Key exclusion criteria (9 listed)

Parathyroidectomy within 24 weeks of study
gastrointestinal bleed or inflammatory bowel disease within 12 weeks of study
Requirement for dialysis or kidney injury within 8 weeks of study
Absolute requirement for oral iron, intravenous iron, Erythropoiesis-Stimulating Agent, blood transfusions, and Sensipar during the study
Absolute requirement for calcium-, magnesium-, or aluminum-containing drugs with meals

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
Ferric CitrateAlso: KRX-0502Dose depends on serum phosphorus levels collected at each study visit.	Drug	Ferric Citrate
Placebo	Drug	Placebo

Primary outcome

Change in Transferrin Saturation (TSAT) From Baseline to End of Treatment
Time frame: 12 Weeks
The difference in TSAT between the value at the end of treatment (week 12) minus the baseline measurement.
Change in Serum Phosphorus Levels From Baseline to End of Treatment
Time frame: 12 Weeks
The difference in serum phosphorus between the value at the end of treatment (week 12) minus the baseline measurement.

2 secondary outcomes

Change in Ferritin Levels From Baseline to End of Treatment
Time frame: 12 Weeks
Change in Hemoglobin Levels From Baseline to End of Treatment
Time frame: 12 Weeks

Results and safety

Results posted to the registry on 20 Oct 2017, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Ferric Citrate	75	61
Placebo	74	50

Primary outcome: Change in Transferrin Saturation (TSAT) From Baseline to End of Treatment

Time frame: 12 Weeks. Mean (Standard Deviation). Unit: % saturation

Measure	Ferric Citrate n = 72	Placebo n = 69
Baseline	21.6 (7.44)	21.0 (8.26)
Week 12	31.7 (14.19)	20.0 (7.55)

Population analysed: Efficacy analyses were based on Intent-to-Treat (ITT) population, which consisted of all randomized subjects who had a baseline laboratory value, had taken at least 1 dose of study drug, \& had at least 1 post-baseline laboratory value. ANCOVA with Last observation carried forward (LOCF) methodology was used.

Primary outcome: Change in Serum Phosphorus Levels From Baseline to End of Treatment

Time frame: 12 Weeks. Mean (Standard Deviation). Unit: mg/dL

Measure	Ferric Citrate n = 72	Placebo n = 69
Baseline	4.5 (0.61)	4.7 (0.60)
12 weeks	3.9 (0.58)	4.4 (0.75)

Population analysed: The efficacy analyses were based on the ITT population. The Intent-to-Treat (ITT) population consisted of all subjects who were randomized into the study, had a baseline laboratory value, had taken at least 1 dose of study drug, and had at least 1 post-baseline laboratory value. ANCOVA with LOCF methodology was used.

2 secondary outcomes are reported in the full results.

Adverse events

Time frame: 12 weeks. Other adverse events reported at 2% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Ferric Citrate	6 of 75 (8%)	52 of 75 (69.3%)	0 of 75
Placebo	9 of 73 (12.3%)	43 of 73 (58.9%)	2 of 73

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2017.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 40576086Natale P, Green SC, Ruospo M, Craig JC, Vecchio M, Elder GJ, Strippoli GF. Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD). Cochrane Database Syst Rev. 2025 Jun 27;6(6):CD006023. doi: 10.1002/14651858.CD006023.pub4.
Derived from this study: PubMed 25468387Block GA, Fishbane S, Rodriguez M, Smits G, Shemesh S, Pergola PE, Wolf M, Chertow GM. A 12-week, double-blind, placebo-controlled trial of ferric citrate for the treatment of iron deficiency anemia and reduction of serum phosphate in patients with CKD Stages 3-5. Am J Kidney Dis. 2015 May;65(5):728-36. doi: 10.1053/j.ajkd.2014.10.014. Epub 2014 Nov 4.

Related trials for Iron Deficiency

RecruitingPhase 4
The Effects of Ferric Derisomaltose in Patients With Acute Heart Failure and Iron Deficiency on Exercise Capacity and Quality of Life(COREVIVE-HFrEF)
Heart Failure With Reduced Ejection Fraction, Iron Deficiency
Recruiting
Iron Absorption From a Nutritional Iron Supplement
Iron Absorption, Iron Deficiencies
RecruitingPhase 4
The Effects of Ferric Derisomaltose in Patients With Acute Heart Failure and Iron Deficiency on Exercise Capacity and Quality of Life
Heart Failure With Preserved Ejection Fraction, Iron Deficiencies
Recruiting
The Effects of Iron Treatment on Vaccine Immunogenicity in Kenyan Infants With Iron Deficiency
Iron Deficiencies
RecruitingPhase 4
The Effects of Low-Dose Versus High-Dose Intravenous IRON Therapy With Ferric DerisomaltOSE in Patients With Chronic Heart Failure and Iron Deficiency
Heart Failure, Iron Deficiency

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. This study is not recruiting at the moment.

Geoffrey Block, MD study chair

Glenn Chertow, MD study chair

Steven Fishbane, MD study chair

20 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Ferric Citrate in people with Iron Deficiency and Iron Deficiency Anemia, run by Keryx Biopharmaceuticals at 20 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 6 inclusion and 9 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: finished, as of the sponsor's last update on 20 Oct 2017. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 20 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. Some participants in this study may receive a placebo. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

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

Are results available for this study?

Yes. Results are posted in the registry (first posted 20 Oct 2017). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Change in Transferrin Saturation (TSAT) From Baseline to End of Treatment (time frame: 12 Weeks). The study lists 2 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 NCT01736397, which also lists 2 linked publications.

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 20 Oct 2017.