A Phase 2 interventional study of Ferric Citrate and Placebo in Chronic Kidney Diseases, sponsored by University of California, Los Angeles. Recruiting at 20 sites in 2 countries. Open to participants aged 6 Years to 18 Years. Per ClinicalTrials.gov, last updated 2026-04-17.
Sponsored by University of California, Los Angeles · Phase 2, Interventional, and Treatment
We will conduct a 12-month, double-blind, randomized, placebo-controlled trial to assess the effects of therapy with ferric citrate (FC) on changes in intact FGF23 levels (iFGF23, primary endpoint) in 160 pediatric patients (80 in each of the two arms) aged 6-18 years of either sex with chronic kidney disease (CKD) stages 3-4 and age-appropriate normal serum phosphate levels. Participants will be randomized to one of the two groups: 1) FC or 2) FC placebo. Participants will be recruited from 20 core clinical sites.
We will conduct a double-blind, randomized, placebo-controlled trial to assess the effects of therapy with ferric citrate (FC) on changes in intact FGF23 levels (iFGF23, primary endpoint) aged 6-18 years of either sex with chronic kidney disease (CKD) stages 3-4 and age-appropriate normal serum phosphate levels. Participants will be randomized to one of the two groups: 1) FC or 2) FC placebo. Participants will be recruited from 20 core clinical sites.
Schedule of Intervention: During the 12-month trial, participants will be given a daily fixed weight-based dose of FC.
Schedule for data collection/analyses to be performed:
Blood for primary outcome assessments will be collected at screening, baseline and at months 3, 6, 9, 12. Blood for safety assessments will be collected at the the months 1, 2, 3, 6, 9, 12.
The primary analyses for this 2-arm trial will compare log-transformed iFGF23 values over 12 months between the treatment and the placebo arms. The analysis will use a linear mixed-effects model, including stratification factors CKD stage and urine protein to creatinine ratio, with random participant effects accounting for repeated measurements, and a fixed treatment effect, which interacts with a time indicator (Months 3-12 vs. Baseline/Screening).
Primary objectives:
Secondary objectives:
Primary Endpoint:
Safety and Tolerability Endpoints:
Secondary Endpoints:
This is a Phase 2 study with participation from 20 sites that will take 36 months to complete enrollment and a total of 48 months to complete data collection with each participant being part of the study for 12 months.
Study website: fit4kid.dgsom.ucla.edu
3,144 studies on the registry are indexed under Renal Insufficiency, Chronic; 704 are open to participants now.
This study's planned enrollment of 160 is above the median of 74 across 2,176 interventional studies indexed under Renal Insufficiency, Chronic.
Browse Renal Insufficiency, Chronic studies →University of California, Los Angeles is the lead sponsor of 1,142 studies on the registry; 192 are open to participants now.
Of its 91 completed or terminated interventional studies of FDA-regulated products, 66 (73%) have results posted.
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Exclusion Criteria:
During the 12-month trial, participants will be given a fixed weight-based dose of Ferric Citrate (FC). The full medication dose will be 3g/day for participants weighing \<31 kg, 5g/day for those weighing \>31 - \<51 kg, and 6g/day for participants \>51 kg. These doses will be divided into three doses to be taken with meals.
Drug: Ferric Citrate
During the 12-month trial, participants will be given a fixed weight-based dose of Placebo. The full medication dose will be 3g/day for participants weighing \<31 kg, 5g/day for those weighing \>31 - \<51 kg, and 6g/day for participants \>51 kg. These doses will be divided into three doses to be taken with meals.
Drug: Placebo
Auryxia® 210 mg ferric iron tablets equivalent to 1 g of FC will be supplied as 200 tablets in 400cc high-density polyethylene bottles.
Also known as: Auryxia
Placebo to match Ferric Citrate tablets
iFGF23 levels
Compared to placebo, active treatment with FC will lower iFGF23 levels
Time frame: 12 months
Safety of Ferric Citrate
Comparing proportion of subjects with AE and SAE between arms
Time frame: 12 months
Tolerability of Ferric Citrate
Compared with placebo, active treatment will be tolerable
Time frame: 12 months
Effects on Transferrin Saturation (TSAT)
Compared with placebo, active treatment with FC will be associated with larger increase in hemoglobin, higher TSAT and higher Ferritin from baseline
Time frame: 12 months
Effects on PTH and 1,25 D
Compared to placebo, active treatment with FC will be associated with a larger decrease in PTH and larger increase in 1,25 D from baseline
Time frame: 12 months
GFR
Compared to placebo, active treatment with FC will be associated with smaller decrease in GFR over time
Time frame: 12 months
Osteoid thickness
Compared to placebo, active treatment with FC will be associated with a larger decrease of osteoid thickness from baseline
Time frame: 12 months
Effects on bone expression
Compared to placebo, active treatment with FC will be associated with a greater reduction in bone expression of FGF23
Time frame: 12 months
Effects on phosphate
Compared to placebo, active treatment with FC will be associated with a greater reduction in 24 hours urinary phosphate and fractional excertion of phosphate
Time frame: 12 months
Effects on calcium
Compared to placebo, active treatment with FC will be associated with a greater incresae in serum calcium levels from baseline
Time frame: 12 months
Effects on 1,25 (OH) D levels
Compared to placebo, active treatment with FC will be associated with a greater increase from baseline in serum 1,25 (OH) D levels
Time frame: 12 months
Effects on bone biomarkers
Compared to placebo, active treatment with FC will be associated with greater reduction from baseline of bone biomarkers of turnover
Time frame: 12 months
Effects on Klotho
Compared to placebo, active treatment with FC will be associated with greater increase from baseline in levels of Klotho
Time frame: 12 months
Effects on cFGF23
Compared to placebo, active treatment with FC will be associated with greater reduction from baseline in cFGF23
Time frame: 12 months
Plan to share: Yes — All de-identified clinical data, including study outcomes and participant characteristics will be submitted to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repository at the completion of the study. De-identified research samples blood and urine will also be provided to the NIDDK central reporsitory
Supporting information: Study protocol, Sap, Icf, Csr, Analytic code
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University of California, Los Angeles