Kidney Transplant; ComplicationsPhase 2NCT03301558
The Effect of Sodium Bicarbonate (Nephrotrans®) on Calcification Propensity of Serum in Kidney Transplant Recipients
A Phase 2 study testing Low dose sodium bicarbonate and High dose sodium bicarbonate in people with Kidney Transplant; Complications, run by Prim. Priv. Doz. Dr. Daniel Cejka at 1 site in Austria.
Trial summary
This is a single-center, prospective, open-label, randomized, cross-over study. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Kidney Transplant; Complications
- What is being tested?
- Low dose sodium bicarbonate and High dose sodium bicarbonate
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 0 participants
- Where
- 1 siteAustria
- Study dates
- 31 Dec 2025to 31 Dec 2025
- Phase
- Phase 2
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults ≥ 18 years old
- Prevalent (≥ 6 months after kidney transplantation) kidney transplant recipients
- eGFR (CKD-EPI formula) between 10 and 50 ml/min/1.73 m²
- Patient has provided informed consent prior to initiation of any study related procedure
Who cannot join
- Allergy to sodium bicarbonate or any component of Nephrotrans®, namely soy or peanuts (reported cross-reactivity to peanuts has been reported in patients with soy-allergy).
- Unstable clinical condition (e.g. uncontrolled heart failure, clinical uremia, uncontrolled hypertension, impending initiation of dialysis treatment…) as judged by the recruiting physician
- Pregnant and nursing (lactating) women
- Unwillingness to discontinue current medication with sodium bicarbonate
- Unwillingness to discontinue antacids containing aluminum, calcium carbonate, magnesium, lactate, citrate, bicarbonate or mixtures thereof
Trial locations and contacts
1 site in 1 country.
Austria1 site
Ordensklinikum Linz GmbH Elisabethinen
Linz, Upper Austria, 4020
About this study
This is a single-center, prospective, open-label, randomized, cross-over study.
Read the detailed description
The primary hypothesis (H1) is that the T50 value will change between wash-out and high-dose (3000mg/d) sodium bicarbonate (Nephrotrans®) substitution.
The 0-hypothesis (H0) is that substitution of 3000 mg/d sodium bicarbonate (Nephrotrans®) has no effect on T50-values as compared to wash-out-phase.
Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between.
Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between. The study will start with an initial run-in wash-out phase, where all sodium bicarbonate or other alkalizing treatment taken by the patient as standard of care will be discontinued. Consequently, there will be a sodium bicarbonate treatment (high dose/low dose) phase, followed by a wash-out phase, followed by another sodium bicarbonate treatment (high dose/low dose) phase, followed by a final wash-out phase. Each study phase, including wash-out phases as well as low-dose and high-dose treatment phases will be 14 ±3 days of duration. Patients will be followed up to 12weeks after randomization until the last study visit of the final wash-out phase.
- Conditions
- Kidney Transplant; Complications
- Being tested
- Low dose sodium bicarbonate, High dose sodium bicarbonate
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low dose sodium bicarbonateDrug
Also called Nephrotrans
1500 mg sodium bicarbonate
High dose sodium bicarbonateDrug
Also called Nephrotrans
3000 mg sodium bicarbonate
| Study group | Role | What they receive |
|---|---|---|
| Low dose sodium bicarbonate | Active comparator | Low dose 1500 mg sodium bicarbonate (Nephrotrans®) per day (500mg tablets 3x/day) for 14 ± 3 days. The patients will be advised to take one capsule with breakfast, one with lunch and one with dinner (schedule 1-1-1). Receives: Drug: Low dose sodium bicarbonate |
| High Dose sodium bicarbonate | Active comparator | High dose 3000 mg of sodium bicarbonate (Nephrotrans®) per day (500mg tablets 3x/day) for 14 ± 3 days. The patients will be advised to take two capsules with breakfast, two with lunch and two with dinner (schedule 2-2-2). Receives: Drug: High dose sodium bicarbonate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Propensity of serum for calcification
The primary outcome is change in the mean T50 values between different study phases (treatment vs. control).
Measured: 12 weeks
Secondary outcomes (1)
Serum bicarbonate levels
The secondary outcome is change of serum bicarbonate levels between different study phases.
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Oct 2017
- Study start31 Dec 2025
- Primary completion31 Dec 2025
- Study completion31 Dec 2025
Why it stopped: due to organizational reason
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Kidney Transplant; ComplicationsStudies 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
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between.
- Masking
- None (open label)
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Prim. Priv. Doz. Dr. Daniel Cejka
- Sponsor type
- University, hospital or other
- Collaborators
- Medice Arzneimittel Pütter GmbH & Co KG
- Responsible party
- Sponsor-investigator, Prim. Priv. Doz. Dr. Daniel Cejka, Elisabethinen Hospital
- Investigators
- Daniela Cejka, MD, Principal investigator, Head of Nephrology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03301558
- Sponsor's protocol ID
- KTR-Bic-T50
- Status last verified
- Sep 2023
- First submitted
- 28 Sep 2017
- Last updated
- 27 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Sodium Bicarbonate (Nephrotrans®) on Calcification Propensity of Serum in Kidney Transplant Recipients
- ClinicalTrials.gov ID
- NCT03301558
- Acronym / sponsor ID
- KTR-Bic-T50
- Conditions
- Kidney Transplant; Complications
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: due to organizational reason
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Prim. Priv. Doz. Dr. Daniel CejkaUniversity, hospital or other
- Collaborators
- Medice Arzneimittel Pütter GmbH & Co KG
- Study start
- 31 Dec 2025 (actual)
- Primary completion
- 31 Dec 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 4 Oct 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a single-center, prospective, open-label, randomized, cross-over study.
Detailed description
The primary hypothesis (H1) is that the T50 value will change between wash-out and high-dose (3000mg/d) sodium bicarbonate (Nephrotrans®) substitution.
The 0-hypothesis (H0) is that substitution of 3000 mg/d sodium bicarbonate (Nephrotrans®) has no effect on T50-values as compared to wash-out-phase.
Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between.
Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between. The study will start with an initial run-in wash-out phase, where all sodium bicarbonate or other alkalizing treatment taken by the patient as standard of care will be discontinued. Consequently, there will be a sodium bicarbonate treatment (high dose/low dose) phase, followed by a wash-out phase, followed by another sodium bicarbonate treatment (high dose/low dose) phase, followed by a final wash-out phase. Each study phase, including wash-out phases as well as low-dose and high-dose treatment phases will be 14 ±3 days of duration. Patients will be followed up to 12weeks after randomization until the last study visit of the final wash-out phase.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between.
| Arm | Type | Receives |
|---|---|---|
| Low dose sodium bicarbonate | Active comparator | Drug: Low dose sodium bicarbonateLow dose 1500 mg sodium bicarbonate (Nephrotrans®) per day (500mg tablets 3x/day) for 14 ± 3 days. The patients will be advised to take one capsule with breakfast, one with lunch and one with dinner (schedule 1-1-1). |
| High Dose sodium bicarbonate | Active comparator | Drug: High dose sodium bicarbonateHigh dose 3000 mg of sodium bicarbonate (Nephrotrans®) per day (500mg tablets 3x/day) for 14 ± 3 days. The patients will be advised to take two capsules with breakfast, two with lunch and two with dinner (schedule 2-2-2). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adults ≥ 18 years old
- Prevalent (≥ 6 months after kidney transplantation) kidney transplant recipients
- eGFR (CKD-EPI formula) between 10 and 50 ml/min/1.73 m²
- Patient has provided informed consent prior to initiation of any study related procedure
Key exclusion criteria (5 listed)
- Allergy to sodium bicarbonate or any component of Nephrotrans®, namely soy or peanuts (reported cross-reactivity to peanuts has been reported in patients with soy-allergy).
- Unstable clinical condition (e.g. uncontrolled heart failure, clinical uremia, uncontrolled hypertension, impending initiation of dialysis treatment…) as judged by the recruiting physician
- Pregnant and nursing (lactating) women
- Unwillingness to discontinue current medication with sodium bicarbonate
- Unwillingness to discontinue antacids containing aluminum, calcium carbonate, magnesium, lactate, citrate, bicarbonate or mixtures thereof
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 |
|---|---|---|
| Low dose sodium bicarbonateAlso: Nephrotrans1500 mg sodium bicarbonate | Drug | Low dose sodium bicarbonate |
| High dose sodium bicarbonateAlso: Nephrotrans3000 mg sodium bicarbonate | Drug | High Dose sodium bicarbonate |
Primary outcome
Propensity of serum for calcification
Time frame: 12 weeks
The primary outcome is change in the mean T50 values between different study phases (treatment vs. control).
1 secondary outcome
Serum bicarbonate levels
Time frame: 12 weeks
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Apr 2026.
- 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.
Daniela Cejka, MD principal investigator
Head of Nephrology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Low dose sodium bicarbonate and High dose sodium bicarbonate in people with Kidney Transplant; Complications, run by Prim. Priv. Doz. Dr. Daniel Cejka at 1 site in Austria.
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 4 inclusion and 5 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: withdrawn, as of the sponsor's last update on 27 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. 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 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?
The study was withdrawn before enrolling participants, so there are no results.
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?
Propensity of serum for calcification (time frame: 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 27 Apr 2026.