Chronic Kidney DiseasesPhase 2/3BICARbNCT05918029
Bone in CKD Alkali Response (BICARb Pilot Trial)
A Phase 2/3 study testing Potassium Citrate Extended Release Oral Tablet and Potassium Citrate and Citric Acid Oral Solution in people with Chronic Kidney Diseases and Bone Loss, run by Albert Einstein College of Medicine at 2 sites in United States.
Trial summary
The goal of this clinical trial is to test whether potassium citrate improves skeletal health in adults and children with chronic kidney disease. The main questions it aims to answer are: To evaluate effects of potassium citrate treatment on bone quality and strength. Read more about this study
- Who is it for?
- Ages 5 to 100 years
- Conditions the study is for
- Chronic Kidney Diseases, Bone Loss
- What is being tested?
- Potassium Citrate Extended Release Oral Tablet and Potassium Citrate and Citric Acid Oral Solution
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 6 participants
- Where
- 2 sitesUnited States
- Study dates
- 15 Aug 2024to 16 May 2025
- Phase
- Phase 2/3
- 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 5 to 100 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Children 5-17 years old
- Estimated glomerular filtration rate (eGFR) ≥ 30 and <90 ml/min/1.73m2 by Chronic Kidney Disease in Children (CKiD) Under 25 (U25) GFR estimating equations
- Females of child-bearing potential must have had a menstrual period in the last month
- Levels of parathyroid hormone (PTH) and alkaline phosphatase within 2x normal range and phosphorus within the normal range for age (per local laboratory reference assay)
- 25-hydroxy Vitamin D ≥ 20 ng/mL
- Females of child-bearing potential must be willing to use one form of effective contraception over the course of the study
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- Proficiency in English or Spanish
- For participants < 18 years, the participant and/or parent/guardian capable of providing informed consent and assent (assessed by the provider)
- Adults ≥ 18 years old
- Estimated eGFR ≥ 30 and <90 ml/min/1.73m2 by the new CKD-Epi without race
- Pre-menopausal women of childbearing age must have had a menstrual period in the last month
- Levels of PTH and alkaline phosphatase within 2x normal range and phosphorus up to 5.0 mg/dL (per local laboratory reference assay)
- Levels of 25-hydroxy Vitamin D ≥ 20 ng/mL
- Women of childbearing potential must be willing to use one form of effective contraception over the course of the study
- Proficiency in English or Spanish
Who cannot join
- Baseline potassium ≥ 5.5 mEq/L or prior history of hyperkalemia in the last 6 months (potassium > 5.5 mEq/L) or currently taking a potassium lowering agent
- Alkali therapy within the prior 12 months
- Baseline ECG with abnormalities associated with increased risk of arrythmia, excluding left ventricular hypertrophy
- Baseline serum bicarbonate levels < 17 or ≥ 30 mEq/L
- Serum calcium < 8.6 mg/dL, adjusted for serum albumin
- Significant comorbidity causing acid-base imbalance (e.g., active cancer requiring chemotherapy, chronic liver failure, moderate or severe chronic obstructive lung disease, New York Heart Association class 2 or greater congestive heart failure, obstructive sleep apnea requiring nightly continuous positive airway pressure, active glomerular disease requiring immunosuppressive therapy, intestinal malabsorption or celiac disease)
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- Plans to relocate out of the area in the next 3 months
- Urine pH > 8 or history of nephrolithiasis
- Lower extremity amputations or non-ambulatory
- Metabolic bone disease not related to CKD (e.g., Paget's disease, primary hyperparathyroidism)
- Endocrinopathy: untreated hyper or hypothyroidism, Cushing's syndrome
- Medical diseases that can affect therapy (severe myocardial damage, acute dehydration, delayed gastric emptying, esophageal compression, or intestinal obstruction or stricture)
- Use of bisphosphonates, denosumab, teriparatide, abaloparatide, romosozumab, raloxifene, estrogen or testosterone replacement therapy, or an unstable dose of glucocorticoids within the 12-months prior to enrollment
- Previous bilateral wrist and tibia fractures
- Solid or liquid organ transplant
- On dialysis or with rapidly deteriorating kidney function or expectation for transplantation or initiation of dialysis in less than 3 months
- Pregnancy or breastfeeding
- Prisoners or institutionalized individuals
- Unwillingness to provide informed consent
Trial locations and contacts
2 sites in 1 country.
United States2 sites
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, 15213
Albert Einstein College of Medicine
The Bronx, New York, 10461
About this study
Official title: Bone in CKD Alkali Response Pilot Trial (BICARb)
The goal of this clinical trial is to test whether potassium citrate improves skeletal health in adults and children with chronic kidney disease. The main questions it aims to answer are:
- To evaluate effects of potassium citrate treatment on bone quality and strength.
- To evaluate mechanism(s) underlying the effects of potassium citrate on skeletal health.
Read more
Participants will be asked to:
- provide blood, urine and answer questions about health and diet three times during an 8 months period
- undergo advanced bone imaging with high resolution-peripheral quantitative CT scan twice during 8 months
- take study pills for 4-6 weeks at the beginning of the study to ensure safety
- take either potassium citrate or placebo for 6 months during the blinded portion of the study
As part of the study, there will be a run-in period followed by the placebo-controlled randomized clinical trial. Researchers will compare the bone imaging between the potassium citrate and the placebo groups at the end of the study.
Read the detailed description
Chronic kidney disease is associated with bone loss and fractures in both children and adults, but bone protective therapies that are both proven and safe to use across the life-course in CKD are lacking. In this study, the investigators will conduct a pilot, double-blinded, randomized, placebo-controlled trial in 15 children and 88 adults evaluating the skeletal effects of potassium alkali therapy. These data will form the basis for a larger U01 proposal to determine the efficacy of potassium citrate on mitigating the effects of CKD on bone.
- Conditions
- Chronic Kidney Diseases, Bone Loss
- Being tested
- Potassium Citrate Extended Release Oral Tablet, Placebo, Potassium Citrate and Citric Acid Oral Solution
- Keywords
- Chronic Kidney Disease, Bone strength, Fractures, Pediatrics, Metabolic acidosis
- Medical subject headings
- Renal Insufficiency, Chronic, Bone Diseases, Metabolic, Fractures, Bone, Acidosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Potassium Citrate Extended Release Oral TabletDrug
Oral potassium citrate extended-release tablet
PlaceboOther
Placebo capsule identical to active ingredient
Potassium Citrate and Citric Acid Oral SolutionDrug
Oral potassium citrate and citric acid
| Study group | Role | What they receive |
|---|---|---|
| Potassium Citrate | Experimental | Potassium Citrate extended-release tablets 30 mEq twice daily. 1 mEq/kg/day divided into two doses for children to a maximum dose of 30 mEq twice daily.
OR
(for children who cannot take pills): Potassium citrate and citric acid for oral solution 1 mEq/kg/day divided into two doses to a maximum dose of 30 mEq twice daily Receives: Drug: Potassium Citrate Extended Release Oral Tablet; Drug: Potassium Citrate and Citric Acid Oral Solution |
| Placebo | Placebo comparator | Placebo capsules identical to the active capsules. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Total Volumetric Bone Mineral Density (BMD) - Distal Radius
Change in total volumetric BMD will be analyzed by high resolution peripheral quantitative computed tomography (HR-pQCT). The 6-month absolute and relative (percent) changes in Z-score in distal radius total volumetric BMD will summarized by study arm and analyzed for between group treatment changes.
Measured: Baseline to 6 months
Change in Total Volumetric Bone Mineral Density (BMD) - Tibia
Change in total volumetric BMD will be analyzed by high resolution peripheral quantitative computed tomography (HR-pQCT). The 6-month absolute and relative (percent) changes in Z-score in tibia total volumetric BMD will summarized by study arm and analyzed for between group treatment changes.
Measured: Baseline to 6 months
Secondary outcomes (4)
Change in 24-hour Urine Net Acid Excretion (NAE)
Change in 24-hour urinary NAE from baseline will be assessed by analyzing samples obtained from 24-hour timed urine collections using laboratory titration methods. Results will be quantified and summarized by study arm using basic descriptive statistics and subsequently analyzed for between group treatment changes. Standard urinary NAE values vary but can range from 250-750 mg/24 hours (1.48 to 4.43 mmol/24 hours).
Measured: Baseline to 6 months
Change in Parathyroid Hormone (PTH) Levels
Change in circulating PTH concentration from baseline will be assessed by the collection of blood samples via venipuncture and analysis for circulating PTH by an immunoassay. Results will be summarized by study arm using basic descriptive statistics and subsequently statistically analyzed for between group changes. Standard PTH reference ranges can vary but are generally between 10-65 pg/mL in plasma.
Measured: Baseline to 6 months
Change in Circulating Biomarkers of Bone Resorption
Change in circulating biomarkers of bone resorption from baseline will be assessed following the collection of blood samples via venipuncture and subsequent analysis for circulating C-terminal telopeptides of type I collagen using a cross-linking telopeptide of type I collagen (CTX blood test) assay. C-terminal telopeptides can be used as a biomarker to measure bone resorption and turnover. Elevated levels of C-terminal telopeptide can be indicative of increased bone resorption. While standard reference ranges for C-terminal telopeptide can vary, for premenopausal women ranges are typically 40-465 pg/mL in serum and 19-83 ug/L in plasma.
Measured: Baseline to 6 months
Change in Circulating Biomarkers of Bone Formation
Change in circulating biomarker of bone formation from baseline will be assessed following the collection of blood samples via venipuncture and subsequent analysis for procollagen type-1 N-terminal propeptide (P1NP). A P1NP assay measures the amount of amino-terminal propeptide of type I procollagen in the serum and can be used as biomarker to measure the rate of bone formation. While reference ranges can vary by age, standard reference ranges in adult premenopausal women are 19-83 ug/L.
Measured: Baseline to 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Jun 2023
- Study start15 Aug 2024
- Primary completion16 May 2025
- Study completion16 May 2025
Why it stopped: DSMB recommended termination due to insufficient accrual rate.
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 (1)Papers the sponsor has linked to this study.
- Other trials for Chronic Kidney DiseasesStudies 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 2/3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 6 participants (actual)
Sponsor and investigators
- Lead sponsor
- Albert Einstein College of Medicine
- Sponsor type
- University, hospital or other
- Collaborators
- Columbia University, University of Pittsburgh Medical Center, University of Utah, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NYU Langone Health, Washington University School of Medicine
- Responsible party
- Sponsor
- Investigators
- Kimberly Reidy, MD, Principal investigator, Albert Einstein College of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05918029
- Sponsor's protocol ID
- 2023-14826
- Other IDs
- R01DK131811, 2023
- Acronym
- BICARb
- Status last verified
- Jun 2026
- First submitted
- 2 Jun 2023
- Last updated
- 28 Jul 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Kilduff S, Brown DD, Melamed ML. Treating Metabolic Acidosis for CKD Progression? Need for Higher Quality Data. Clin J Am Soc Nephrol. 2025 Jan 1;20(1):147-149. doi: 10.2215/CJN.0000000632. Epub 2024 Nov 20. No abstract available.
PubMed 39665575
Study at a glance
From the registry record, last updated by the sponsor on 28 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bone in CKD Alkali Response Pilot Trial (BICARb)
- ClinicalTrials.gov ID
- NCT05918029
- Acronym / sponsor ID
- BICARb / 2023-14826
- Conditions
- Chronic Kidney Diseases, Bone Loss
- Keywords
- Chronic Kidney Disease, Bone strength, Fractures, Pediatrics, Metabolic acidosis
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: DSMB recommended termination due to insufficient accrual rate.
- Enrolment
- 6 participants (actual)
- Lead sponsor
- Albert Einstein College of MedicineUniversity, hospital or other
- Collaborators
- Columbia University, University of Pittsburgh Medical Center, University of Utah, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NYU Langone Health, Washington University School of Medicine
- Study start
- 15 Aug 2024 (actual)
- Primary completion
- 16 May 2025 (actual)
- Study completion
- 16 May 2025 (actual)
- First posted
- 26 Jun 2023 (actual)
- Results
- Posted 28 Jul 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to test whether potassium citrate improves skeletal health in adults and children with chronic kidney disease. The main questions it aims to answer are:
- To evaluate effects of potassium citrate treatment on bone quality and strength.
- To evaluate mechanism(s) underlying the effects of potassium citrate on skeletal health.
Participants will be asked to:
- provide blood, urine and answer questions about health and diet three times during an 8 months period
- undergo advanced bone imaging with high resolution-peripheral quantitative CT scan twice during 8 months
- take study pills for 4-6 weeks at the beginning of the study to ensure safety
- take either potassium citrate or placebo for 6 months during the blinded portion of the study
As part of the study, there will be a run-in period followed by the placebo-controlled randomized clinical trial. Researchers will compare the bone imaging between the potassium citrate and the placebo groups at the end of the study.
Detailed description
Chronic kidney disease is associated with bone loss and fractures in both children and adults, but bone protective therapies that are both proven and safe to use across the life-course in CKD are lacking. In this study, the investigators will conduct a pilot, double-blinded, randomized, placebo-controlled trial in 15 children and 88 adults evaluating the skeletal effects of potassium alkali therapy. These data will form the basis for a larger U01 proposal to determine the efficacy of potassium citrate on mitigating the effects of CKD on bone.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Potassium Citrate | Experimental | Drug: Potassium Citrate Extended Release Oral Tablet, Drug: Potassium Citrate and Citric Acid Oral SolutionPotassium Citrate extended-release tablets 30 mEq twice daily. 1 mEq/kg/day divided into two doses for children to a maximum dose of 30 mEq twice daily. OR (for children who cannot take pills): Potassium citrate and citric acid for oral solution 1 mEq/kg/day divided into two doses to a maximum dose of 30 mEq twice daily |
| Placebo | Placebo comparator | Other: PlaceboPlacebo capsules identical to the active capsules. |
Who may qualify
- Ages
- 5 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (15 listed)
- Children 5-17 years old
- Estimated glomerular filtration rate (eGFR) ≥ 30 and <90 ml/min/1.73m2 by Chronic Kidney Disease in Children (CKiD) Under 25 (U25) GFR estimating equations
- Females of child-bearing potential must have had a menstrual period in the last month
- Levels of parathyroid hormone (PTH) and alkaline phosphatase within 2x normal range and phosphorus within the normal range for age (per local laboratory reference assay)
- 25-hydroxy Vitamin D ≥ 20 ng/mL
Key exclusion criteria (19 listed)
- Baseline potassium ≥ 5.5 mEq/L or prior history of hyperkalemia in the last 6 months (potassium > 5.5 mEq/L) or currently taking a potassium lowering agent
- Alkali therapy within the prior 12 months
- Baseline ECG with abnormalities associated with increased risk of arrythmia, excluding left ventricular hypertrophy
- Baseline serum bicarbonate levels < 17 or ≥ 30 mEq/L
- Serum calcium < 8.6 mg/dL, adjusted for serum albumin
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 |
|---|---|---|
| Potassium Citrate Extended Release Oral TabletOral potassium citrate extended-release tablet | Drug | Potassium Citrate |
| PlaceboPlacebo capsule identical to active ingredient | Other | Placebo |
| Potassium Citrate and Citric Acid Oral SolutionOral potassium citrate and citric acid | Drug | Potassium Citrate |
Primary outcome
Change in Total Volumetric Bone Mineral Density (BMD) - Distal Radius
Time frame: Baseline to 6 months
Change in total volumetric BMD will be analyzed by high resolution peripheral quantitative computed tomography (HR-pQCT). The 6-month absolute and relative (percent) changes in Z-score in distal radius total volumetric BMD will summarized by study arm and analyzed for between group treatment changes.
Change in Total Volumetric Bone Mineral Density (BMD) - Tibia
Time frame: Baseline to 6 months
Change in total volumetric BMD will be analyzed by high resolution peripheral quantitative computed tomography (HR-pQCT). The 6-month absolute and relative (percent) changes in Z-score in tibia total volumetric BMD will summarized by study arm and analyzed for between group treatment changes.
4 secondary outcomes
Change in 24-hour Urine Net Acid Excretion (NAE)
Time frame: Baseline to 6 months
Change in Parathyroid Hormone (PTH) Levels
Time frame: Baseline to 6 months
Change in Circulating Biomarkers of Bone Resorption
Time frame: Baseline to 6 months
Change in Circulating Biomarkers of Bone Formation
Time frame: Baseline to 6 months
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jul 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 39665575Kilduff S, Brown DD, Melamed ML. Treating Metabolic Acidosis for CKD Progression? Need for Higher Quality Data. Clin J Am Soc Nephrol. 2025 Jan 1;20(1):147-149. doi: 10.2215/CJN.0000000632. Epub 2024 Nov 20. No abstract available.
- Individual participant dataSharing planned: No
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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.
Kimberly Reidy, MD principal investigator
Albert Einstein College of Medicine
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Potassium Citrate Extended Release Oral Tablet and Potassium Citrate and Citric Acid Oral Solution in people with Chronic Kidney Diseases and Bone Loss, run by Albert Einstein College of Medicine at 2 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 19 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: stopped early, as of the sponsor's last update on 28 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 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 combined 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.
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?
Yes. Results are posted in the registry (first posted 28 Jul 2026). 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 Total Volumetric Bone Mineral Density (BMD) - Distal Radius (time frame: Baseline to 6 months). 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 NCT05918029, which also lists 1 linked publication.
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 28 Jul 2026.