Manipulating the Gut Microbiome Study

November 18, 2021 updated by: Nicholas Ah Mew
The objective is to determine if acetohydroxamic acid (AHA) can prevent hydrolysis of urea by inhibiting the bacterial urease of gut flora of both healthy control adults as well as adults with urea cycle disorders

Study Overview

Status

Status

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

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

This project will study the efficacy and safety of the pharmacologic blockade of urease in the nitrogen salvage pathway of intestinal microbes in subjects with partial urea cycle disorders. Additional trapping of ammonia as excretable urea may result in improved nitrogen excretion and reduced ammonia levels.

Urea cycle disorders (UCDs) are a group of disorders resulting from a complete or partial deficiency of one of the 6 enzymes or 2 transporters that comprise the urea cycle, the essential biochemical pathway which converts toxic ammonia into urea. These disorders have as a common feature, a reduced or complete inability to convert ammonia into urea, thereby resulting in high ammonia levels, or hyperammonemia. If untreated, hyperammonemia may result acutely in lethargy and coma, and chronically in intellectual disability. Current treatment for hyperammonemia is suboptimal, thus the search for new treatments is critical.

The urease inhibitor, acetohydroxamic acid (AHA, Lithostat®, Mission Pharmacal), is an FDA-approved product for another indication- the treatment of struvite nephrolithiasis in chronic urinary tract infections in both adults and children.

It is known that many urea-splitting bacteria also exist in the gut, and that in healthy individuals, approximately 15-30% of blood urea is degraded via gut bacteria into ammonia3, which returns to the liver via the portal vein, only to be recycled into urea. This percentage of degraded urea may even be greater in patients with urea cycle disorders, who are on a low protein-diet4 and whose gastrointestinal contents thus likely have lower nitrogen content, promoting bacterial recycling of nitrogen from available urea. Additionally, urea hydrolysis has been shown to be greatest in infants5, precisely the age at which hyperammonemic episodes are the most frequent in UCD patients.

We intend to study if AHA can inhibit gut bacteria degradation of urea, thereby reducing the quantity of ammonia returning to the liver. We intend to investigate this by studying subjects on two occasions at least 3 days apart:

On the first occasion, subjects will receive an intravenous dose of 13C-urea. Following the intravenous bolus of 13C-urea, over the subsequent 4 hours, we will collect several sequential measurements of blood and urine biomarkers from an IV catheter placed in the other arm. The intent is to obtain baseline 13CO2 kinetics in the subject.

On the second occasion, subjects will first receive an oral dose of AHA approximately 1 hour prior to the intravenous 13C-urea dose. Similar sequential measurements of blood and urine biomarkers will be performed. The intent is to observe a reduction in 13CO2 when AHA is administered.

We intend to initially study a cohort of unaffected adult subjects. If successful, we will study adults with partial urea cycle disorders.

This study will be conducted in the Clinical Research Center (CRC) of the Clinical and Translational Research Institute (CTSI) of Children's National Medical Center (CNMC).

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

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
4

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
  • Phase 1

Contacts and Locations

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

Study Locations

  • United States
    • District of Columbia
      • Washington, District of Columbia, United States, 20010
        • Children's National Medical Center

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

14 years to 56 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • For Group 1 (healthy adults):
  • Ages 18-60 years
  • Compliant with receiving medications orally and intravenously
  • Compliant with providing blood and urine samples

For Group 2 (adult UCD patients):

  • Ages 18-60 years
  • Compliant with receiving medications orally and intravenously
  • Compliant with providing blood and urine samples

  • Established diagnosis of CPSD, OTCD, ASSD or ASLD as follows:

    • Diagnosis of CPS I deficiency, defined as decreased (less than 20 % of control) CPS I enzyme activity in liver or an identified pathogenic mutation
    • Diagnosis of OTC deficiency, defined as the identification of a pathogenic mutation, linkage analysis in an affected family, less than 20% of control of OTC activity in the liver, or elevated urinary orotate (greater than 20 uM/mM) in a random sample or following allopurinol loading with absence of argininosuccinic acid
    • Diagnosis of AS deficiency (Citrullinemia), defined as a greater than or equal to 10-fold elevation of citrulline in plasma, decreased AS enzyme activity in cultured skin fibroblasts or other appropriate tissue, or identification of a pathogenic mutation in the AS gene
    • Diagnosis of AL deficiency (Argininosuccinic Aciduria, ASA), defined as the presence of argininosuccinic acid in the blood or urine, decreased AL enzyme activity in cultured skin fibroblasts or other appropriate tissue, or identification of a pathogenic mutation in the AL gene

Exclusion Criteria:

  • For both Group 1 and Group 2:
  • Current or prior Helicobacter pylori infection
  • Chronic gastrointestinal illness (e.g., inflammatory bowel disease)
  • Chronic renal failure
  • Taking probiotic medications within a week of study start date
  • Currently pregnant or lactating. Documentation of a negative pregnancy test within a week prior to testing is required, unless pre-menarchal or menopausal, experiencing menses that week, or other circumstances which preclude pregnancy (e.g. hysterectomy).
  • Presence of acute infection at the time of inclusion
  • Participation in any other clinical interventional trial or received experimental medication within the last 30 days
  • Any clinical or laboratory abnormality or medical condition that, at the discretion of the investigator, may put the subject at an additional risk by participating in this study

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: Treatment
  • 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.
Experimental: Acetohydroxamic Acid Oral Tablet then No Intervention
Participants receive a single oral dose of 60 mg/kg acetohydroxamic acid (rounded to the nearest 250 mg) in the fasted state on the morning of the study. After completion of the 4-h study, participants then enter a wash-out period of 3 days. Participants then completed an identical 4-h study in the fasted state without acetohydroxamic acid.
Drug: Acetohydroxamic Acid Oral Tablet
A single oral dose of 60 mg/kg acetohydroxamic acid rounded to the nearest 250 mg tablet.
Other Names:
  • Lithostat
Other: No treatment
No treatment
Experimental: No Intervention then Acetohydroxamic Acid Oral Tablet
Participants completed a 4-h study in the fasted state without acetohydroxamic acid. 3 days later, participants then completed an identical 4-h study in the fasted state, after having received a single oral dose of 60 mg/kg acetohydroxamic acid (rounded to the nearest 250 mg).
Drug: Acetohydroxamic Acid Oral Tablet
A single oral dose of 60 mg/kg acetohydroxamic acid rounded to the nearest 250 mg tablet.
Other Names:
  • Lithostat
Other: No treatment
No treatment

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
Atom Percent Excess of 13CO2
Time Frame: Time +0 minutes, +30 minutes, +60 minutes, +90 minutes, +120 minutes, +180 minutes, and +240 minutes from time of infused [13C] Urea IV
Difference in the % enrichment of Carbon-13 in blood CO2 as compared to baseline measurement, at sequential time points, after a single bolus of intravenous [13C]-Urea,
Time +0 minutes, +30 minutes, +60 minutes, +90 minutes, +120 minutes, +180 minutes, and +240 minutes from time of infused [13C] Urea IV

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
Blood [13C]-Urea
Time Frame: Time +O minutes, +30 minutes, +60 minutes, +90 minutes, +120 minutes, +180 minutes, and +240 minutes from time of [13C] Urea IV
Concentration of urea labeled with Carbon-13
Time +O minutes, +30 minutes, +60 minutes, +90 minutes, +120 minutes, +180 minutes, and +240 minutes from time of [13C] Urea IV

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.
Nicholas Ah Mew

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: Nicholas Ah Mew, MD, Children's National Research Institute

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.
March 24, 2017

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.
June 5, 2018

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.
June 5, 2018

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).
June 1, 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.
June 7, 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.
June 9, 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.
December 15, 2021

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.
November 18, 2021

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.
November 1, 2021

More Information

Terms related to this study

Keywords

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.
  • #7230

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

Yes

Studies a U.S. FDA-regulated device product

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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