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A Safety and Tolerability Study of Zerenex (Ferric Citrate) in Patients With End-Stage Renal Disease (ESRD)

This study has been completed.
Collaborative Study Group (CSG)
Information provided by (Responsible Party):
Keryx Biopharmaceuticals Identifier:
First received: March 27, 2008
Last updated: March 3, 2017
Last verified: March 2017
This study is to evaluates the safety and tolerability of Zerenex™ (ferric citrate) as a treatment for hyperphosphatemia in patients with End-Stage Renal Disease.

Condition Intervention Phase
End-stage Renal Disease
Drug: ferric citrate
Phase 2

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: No masking
Primary Purpose: Treatment
Official Title: A Safety and Tolerability Study of Zerenex (Ferric Citrate) in Patients With End-Stage Renal Disease (ESRD)

Resource links provided by NLM:

Further study details as provided by Keryx Biopharmaceuticals:

Primary Outcome Measures:
  • The Difference in Serum Phosphorus Between Baseline (Day 0) and End of Treatment (Day 28) [ Time Frame: 28 days ]

Enrollment: 55
Study Start Date: March 2008
Study Completion Date: January 2009
Primary Completion Date: January 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: KRX-0502 (ferric citrate)
All patients will be switched from their current phosphate binder to Zerenex, and titrated to the maximum tolerated dose (up to about 12g/day) based on their serum phosphorus levels.
Drug: ferric citrate
ferric citrate will be provided as a 375mg capsule. Dosing and frequency are dependent on patient's serum phosphorus levels. Dosing will occur over the 28-day study.
Other Name: KRX-0502

Detailed Description:
The purpose of this study is to evaluate the safety and tolerability of Zerenex™ (ferric citrate) as a treatment for hyperphosphatemia in patients with End-Stage Renal Disease. These patients will be switched to Zerenex™ from their current high dose of phosphate binder and, based on their serum phosphorus levels, will be titrated up from 3.4g/day of Zerenex™ to maximum tolerated and safe doses of Zerenex™. Doses will be adjusted weekly, based on serum phosphorus levels, with the maximum dose administered being approximately 12g/day.

Ages Eligible for Study:   19 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Males and non-pregnant, nonlactating females
  • Age > 18 years
  • On thrice weekly hemodialysis for at least the previous 3 months prior to randomization
  • Phosphorous levels ≥3.5mg/dL at Screening Visit
  • On at least 12 tablets/capsules/day of calcium acetate (667mg), calcium carbonate (500mg), lanthanum carbonate (500mg), sevelamer hydrochloride (800mg or two 400mg tablets), or any combination of these agents
  • Serum ferritin <1000micrograms/L and Transferrin Saturation (TSAT) <50%
  • Willing to be discontinued from current phosphate binder(s) and initiated on Zerenex
  • Willing and able to give informed consent

Exclusion Criteria:

  • Parathyroidectomy within 6 months prior to Screening
  • Actively symptomatic GI disease such as peptic ulcer disease, gastro esophageal reflux, diverticulosis, irritable bowel syndrome (treated asymptomatic is permitted)
  • History of documented inflammatory bowel disease or erosive esophagitis
  • Serum Phosphorus levels >10.0 mg/dL documented in the 3 monthly laboratories (done routinely in the dialysis unit) in the 3 months prior to the Screening Visit
  • History of multiple drug allergies
  • History of malignancy in the last 5 years (treated cervical or skin cancer may be permitted if approved by CCC)
  • Previous intolerance to oral ferric citrate
  • Absolute requirement for oral iron therapy
  • Absolute requirement for Vitamin C (multivitamins [Neprocaps, Renaphro, etc.] allowed)
  • Absolute requirement for calcium, magnesium, or aluminum containing drugs with meals
  • Psychiatric disorder that interferes with the patient's ability to comply with the study protocol
  • Inability to tolerate oral drug intake
  • Planned surgery or hospitalization during the study (scheduled outpatient access surgery allowed)
  • Any other medical condition that renders the patient unable to or unlikely to complete the study or that would interfere with optimal participation in the study or produce significant risk to the patient
  • Receipt of any investigational drug within 30 days of randomization
  • Inability to cooperate with study personnel or history of noncompliance
  Contacts and Locations
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Please refer to this study by its identifier: NCT00648167

United States, Tennessee
Vanderbilt University Medical Center
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Keryx Biopharmaceuticals
Collaborative Study Group (CSG)
Study Chair: Julia B Lewis, MD Collaborative Study Group at the Nephrology Clinical Trials Center, Vanderbilt University Medical Center
  More Information

Additional Information:
Responsible Party: Keryx Biopharmaceuticals Identifier: NCT00648167     History of Changes
Other Study ID Numbers: KRX-0502-201
Study First Received: March 27, 2008
Results First Received: October 4, 2014
Last Updated: March 3, 2017
Individual Participant Data  
Plan to Share IPD: No

Keywords provided by Keryx Biopharmaceuticals:
end-stage renal disease
end stage renal disease
kidney failure
renal failure
phosphate binder

Additional relevant MeSH terms:
Kidney Diseases
Kidney Failure, Chronic
Renal Insufficiency, Chronic
Urologic Diseases
Renal Insufficiency
Phosphorus Metabolism Disorders
Metabolic Diseases
Citric Acid
Ferric Compounds
Calcium Chelating Agents
Chelating Agents
Sequestering Agents
Molecular Mechanisms of Pharmacological Action
Hematinics processed this record on April 27, 2017