Urea Cycle DisordersNCT05671666
Ureagenesis Analysis in Healthy Subjects and in Urea Cycle Disorder Patients
A study testing Urea cycle flux study in people with Urea Cycle Disorders, run by University Children's Hospital, Zurich at 1 site in Switzerland.
Trial summary
Urea cycle disorders (UCDs) are dramatic congenital inherited metabolic disorders. There is no cure. Many novel therapeutic approaches are currently being developed, which hopefully will change the current situation. Read more about this study
- Who is it for?
- Any ageHealthy volunteers can take part
- Conditions the study is for
- Urea Cycle Disorders
- What is being tested?
- Urea cycle flux study
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteSwitzerland
- Study dates
- 31 Oct 2019to 31 Dec 2035
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 Any age
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- healthy subjects at any age and given written informed consent
- subjects with a UCD confirmed by genetic or enzymatic diagnostics at any age and given written informed consent
Who cannot join
- healthy subjects with acute and chronic disease requiring treatment of any kind
- pregnant or lactating women.
- UCD patients with acute and chronic (other than her/his UCD) disease requiring treatment
- UCD patients in which intake of carglumic acid cannot be stopped for 24 hours prior to the test
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site, 1 recruiting
- Recruiting
University Children's Hospital
Zurich, Canton of Zurich, 8008
Johannes Haeberle, +41442667342, johannes.haeberle@kispi.uzh.ch
About this study
Urea cycle disorders (UCDs) are dramatic congenital inherited metabolic disorders. There is no cure. Many novel therapeutic approaches are currently being developed, which hopefully will change the current situation. Testing the efficacy of such new therapies in patients is a challenge, because many clinical parameters are influenced by several disturbances and biochemical parameters are often not very specific.
The measurement of ureagenesis is a tool to analyze the entire function of the urea cycle in a single test. This is more meaningful for the characterization of UCD patients than the analysis of single metabolites or enzymes. Therefore, the test will be important to evaluate current and future novel therapies.
Read more
The term "ureagenesis" means "production of urea", which is the main task of the urea cycle. This total urea production can be measured with a "tracer" (in this case a stable ammonium chloride isotope). This tracer is non-radioactive and non-toxic. It is for example used as an unmarked substance in cough syrup, diuretic drugs and as food additive. Thus, the tracer does not pose a risk to the participant, especially since only a very low dose is applied.
The investigators will analyze specific substances from the urea cycle (namely [15N, 14N] urea and several [15N] amino acids) that are produced during the test and compare them with results from healthy people. Venous and capillary blood will be sampled at 15 to 30 minutes intervals up to 2 hours after administration of the stable isotope tracer. The maximum test duration is 5 hours.
This project is being carried out at one site, namely the University Children's Hospital in Zurich.
This project is being carried out under Swiss law. The responsible Ethics Committee has reviewed and approved the study.
- Conditions
- Urea Cycle Disorders
- Being tested
- Urea cycle flux study
- Medical subject headings
- Urea Cycle Disorders, Inborn
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Urea cycle flux studyDiagnostic test
Quantification of ureagenesis
| Study group | Role | What they receive |
|---|---|---|
| Healthy controls or UCD patients | Other | Not described Receives: Diagnostic Test: Urea cycle flux study |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rate of flux through the urea cycle using stable isotopes in healthy subjects and patients, and the change of rate of flux through the urea cycle in patients after an intervention or for follow-up.
Measurement of total concentrations of urea in plasma (in mmol/L) and amino acids in plasma (in micromol/L) and their enrichment (in %) after application of a stable isotope tracer by using a high-resolution liquid chromatography mass spectrometry (LC MS) method.
Measured: Baseline for healthy subjects and patients and post-intervention (up to 1 year after the intervention) for patients
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jan 2023
- Study start31 Oct 2019
- Primary completion31 Dec 2035 (estimated)
- Study completion31 Dec 2035 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Urea Cycle DisordersStudies 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 N/A
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Children's Hospital, Zurich
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05671666
- Sponsor's protocol ID
- Ureagenesis01352
- Status last verified
- Mar 2025
- First submitted
- 1 Nov 2022
- Last updated
- 8 Jan 2026
- Results posted
- 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 8 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ureagenesis Analysis in Healthy Subjects and in Urea Cycle Disorder Patients
- ClinicalTrials.gov ID
- NCT05671666
- Acronym / sponsor ID
- Ureagenesis01352
- Conditions
- Urea Cycle Disorders
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University Children's Hospital, ZurichUniversity, hospital or other
- Study start
- 31 Oct 2019 (actual)
- Primary completion
- 31 Dec 2035 (estimated)
- Study completion
- 31 Dec 2035 (estimated)
- First posted
- 5 Jan 2023 (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.
Urea cycle disorders (UCDs) are dramatic congenital inherited metabolic disorders. There is no cure. Many novel therapeutic approaches are currently being developed, which hopefully will change the current situation. Testing the efficacy of such new therapies in patients is a challenge, because many clinical parameters are influenced by several disturbances and biochemical parameters are often not very specific.
The measurement of ureagenesis is a tool to analyze the entire function of the urea cycle in a single test. This is more meaningful for the characterization of UCD patients than the analysis of single metabolites or enzymes. Therefore, the test will be important to evaluate current and future novel therapies.
The term "ureagenesis" means "production of urea", which is the main task of the urea cycle. This total urea production can be measured with a "tracer" (in this case a stable ammonium chloride isotope). This tracer is non-radioactive and non-toxic. It is for example used as an unmarked substance in cough syrup, diuretic drugs and as food additive. Thus, the tracer does not pose a risk to the participant, especially since only a very low dose is applied.
The investigators will analyze specific substances from the urea cycle (namely [15N, 14N] urea and several [15N] amino acids) that are produced during the test and compare them with results from healthy people. Venous and capillary blood will be sampled at 15 to 30 minutes intervals up to 2 hours after administration of the stable isotope tracer. The maximum test duration is 5 hours.
This project is being carried out at one site, namely the University Children's Hospital in Zurich.
This project is being carried out under Swiss law. The responsible Ethics Committee has reviewed and approved the study.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy controls or UCD patients | Other | Diagnostic Test: Urea cycle flux study |
Who may qualify
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (2 listed)
- healthy subjects at any age and given written informed consent
- subjects with a UCD confirmed by genetic or enzymatic diagnostics at any age and given written informed consent
Key exclusion criteria (4 listed)
- healthy subjects with acute and chronic disease requiring treatment of any kind
- pregnant or lactating women.
- UCD patients with acute and chronic (other than her/his UCD) disease requiring treatment
- UCD patients in which intake of carglumic acid cannot be stopped for 24 hours prior to the test
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 |
|---|---|---|
| Urea cycle flux studyQuantification of ureagenesis | Diagnostic test | Healthy controls or UCD patients |
Primary outcome
Rate of flux through the urea cycle using stable isotopes in healthy subjects and patients, and the change of rate of flux through the urea cycle in patients after an intervention or for follow-up.
Time frame: Baseline for healthy subjects and patients and post-intervention (up to 1 year after the intervention) for patients
Measurement of total concentrations of urea in plasma (in mmol/L) and amino acids in plasma (in micromol/L) and their enrichment (in %) after application of a stable isotope tracer by using a high-resolution liquid chromatography mass spectrometry (LC MS) method.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jan 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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Urea cycle flux study in people with Urea Cycle Disorders, run by University Children's Hospital, Zurich at 1 site in Switzerland.
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 2 inclusion and 4 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: looking for participants now, as of the sponsor's last update on 8 Jan 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 Switzerland. 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.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Johannes Häberle (0041-442495988, Johannes.haeberle@kispi.uzh.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rate of flux through the urea cycle using stable isotopes in healthy subjects and patients, and the change of rate of flux through the urea cycle in patients after an intervention or for follow-up. (time frame: Baseline for healthy subjects and patients and post-intervention (up to 1 year after the intervention) for patients). 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 8 Jan 2026.