The Effect of Sodium Bicarbonate (Nephrotrans®) on Calcification Propensity of Serum in Kidney Transplant Recipients

April 22, 2026 updated by: Prim. Priv. Doz. Dr. Daniel Cejka
This is a single-center, prospective, open-label, randomized, cross-over study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Austria
    • Upper Austria
      • Linz, Upper Austria, Austria, 4020
        • Ordensklinikum Linz GmbH Elisabethinen

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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

Exclusion Criteria:

  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Low dose sodium bicarbonate
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).
Drug: Low dose sodium bicarbonate
1500 mg sodium bicarbonate
Other Names:
  • Nephrotrans
Active Comparator: High Dose sodium bicarbonate
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).
Drug: High dose sodium bicarbonate
3000 mg sodium bicarbonate
Other Names:
  • Nephrotrans

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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).
12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Serum bicarbonate levels
Time Frame: 12 weeks
The secondary outcome is change of serum bicarbonate levels between different study phases.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Prim. Priv. Doz. Dr. Daniel Cejka

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Medice Arzneimittel Pütter GmbH & Co KG

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Daniela Cejka, MD, Head of Nephrology

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 31, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 28, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 3, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 4, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2023

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • KTR-Bic-T50

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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