Calcium Oxalate UrolithiasisNCT03752684
Oxalobacter Formigenes Colonization and Urinary Oxalate Excretion
A study testing Moderately high oxalate/low calcium diet non-colonized, Oxalobacter formigenes and Moderately high oxalate/low calcium diet colonized in people with Calcium Oxalate Urolithiasis, run by University of Alabama at Birmingham at 1 site in United States.
Trial summary
The purpose of this research study is to assess the efficacy of ingesting a small amount of the harmless bacterium Oxalobacter formigenes in establishing residence in the guts of healthy participants and to determine whether this influences the oxalate passed in urine. Read more about this study
- Who is it for?
- Ages 19 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Calcium Oxalate Urolithiasis
- What is being tested?
- Moderately high oxalate/low calcium diet non-colonized, Oxalobacter formigenes and Moderately high oxalate/low calcium diet colonized
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 26 participants
- Where
- 1 siteUnited States
- Study dates
- 2 Apr 2018to 22 May 2025
- Phase
- Interventional
- 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 19 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Good health as judged from a medical history and reported medications
- Not colonized with O. formigenes
Who cannot join
- History of any hepatic, renal, bowel or endocrine disease or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results
- colonized with O. formigenes
- abnormal urine chemistries or blood metabolic profiles
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Alabama at Birmingham
Birmingham, Alabama, 35294
About this study
Official title: Oxalobacter Formigenes Colonization and Oxalate Excretion in Healthy Adults
The purpose of this research study is to assess the efficacy of ingesting a small amount of the harmless bacterium Oxalobacter formigenes in establishing residence in the guts of healthy participants and to determine whether this influences the oxalate passed in urine.
Read the detailed description
Adults that are not colonized with O. formigenes, have no history of stone disease, and are in good health as judged by their medical history and a complete metabolic profile of their serum, will be recruited from within the greater Birmingham area.
Participants not colonized with O. formigenes will consume a controlled diet containing moderately high levels of oxalate (210-240 mg per day), and low levels of calcium (500 - 700 mg per day) and collect 24-hour urines to measure oxalate excretion. Following completion of urine collections, participants will ingest live O.formigenes and one week later stool will be provided to test for colonization with O.formigenes. Participants that are successfully colonized with O.formigenes will then repeat 24 hour urine collections on the same high oxalate, low calcium diet. Controlled diets will be prepared in the Metabolic Kitchen of the UAB Clinical Research Unit (CRU). Sustainability of colonization will be determined over time. Loss of colonization will be confirmed by having the subject consume an oxalate-rich meal with subsequent testing for O. formigenes.
- Conditions
- Calcium Oxalate Urolithiasis
- Being tested
- Moderately high oxalate/low calcium diet non-colonized, Oxalobacter formigenes, Moderately high oxalate/low calcium diet colonized
- Keywords
- Oxalobacter formigenes, oxalate, kidney stones
- Medical subject headings
- Nephrolithiasis, Calcium Oxalate, Kidney Calculi
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Moderately high oxalate/low calcium diet non-colonizedDietary supplement
Subjects will be instructed to ingest a controlled diet moderately high in oxalate before colonization
Oxalobacter formigenesDietary supplement
Subjects will ingest live preparation of O. formigenes
Moderately high oxalate/low calcium diet colonizedDietary supplement
Subjects will be instructed to ingest a controlled diet moderately high in oxalate after colonization
| Study group | Role | What they receive |
|---|---|---|
| Colonization with Oxalobacter formigenes | Experimental | Subjects not colonized with Oxalobacter formigenes will be equilibrated to a moderately high oxalate/ low calcium oxalate controlled diet and collect 24-hour urines to measure oxalate excretion Subjects will then be colonized with Oxalobacter formigenes(Intervention). Following colonization with Oxalobacter formigenes, urinary oxalate will be measured to determine the impact of colonization on the same controlled diet Receives: Dietary Supplement: Moderately high oxalate/low calcium diet non-colonized; Dietary Supplement: Oxalobacter formigenes; Dietary Supplement: Moderately high oxalate/low calcium diet colonized |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percent Decrease in Urinary Oxalate Excretion After Colonization With O.Formigenes
Mean 24-hour urine oxalate excretion after colonization with O.formigenes was compared with mean 24-hour urine oxalate before colonization
Measured: 4 days
Secondary outcomes (1)
Percentage Decrease in Stool Oxalate Content After Colonization With O.Formigenes
Mean stool oxalate content after colonization with O.formigenes was compared with mean stool oxalate before colonization
Measured: 4 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2018
- Study start2 Apr 2018
- Primary completion27 Apr 2023
- Study completion22 May 2025
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 Calcium Oxalate UrolithiasisStudies of the same condition, open and under way.
- More trials run by University of Alabama at BirminghamThe sponsor's other registered studies.
- 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
- Basic science
- Allocation
- Not applicable
- Intervention model
- Sequential
- Model description
- Evaluate urinary oxalate excretion before and after colonization with the oxalate degrading bacterium Oxalobacter formigenes
- Masking
- None (open label)
- Enrolment
- 26 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Alabama at Birmingham
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, John Knight, University of Alabama at Birmingham
- Investigators
- John Knight, PhD, Principal investigator, University of Alabama at Birmingham
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03752684
- Sponsor's protocol ID
- IRB-131212001
- Other IDs
- R01DK087967
- Status last verified
- Jan 2026
- First submitted
- 22 Oct 2018
- Last updated
- 30 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Suryavanshi M, Franklin A, Fargue S, Assimos DG, Knight J, Miller AW. Baseline abundance of oxalate-degrading bacteria determines response to Oxalobacter formigenes probiotic therapy. Gut Microbes. 2025 Dec 31;17(1):2562337. doi: 10.1080/19490976.2025.2562337. Epub 2025 Sep 23.
PubMed 40984794
Study at a glance
From the registry record, last updated by the sponsor on 30 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Oxalobacter Formigenes Colonization and Oxalate Excretion in Healthy Adults
- ClinicalTrials.gov ID
- NCT03752684
- Acronym / sponsor ID
- IRB-131212001
- Conditions
- Calcium Oxalate Urolithiasis
- Keywords
- Oxalobacter formigenes, oxalate, kidney stones
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 26 participants (actual)
- Lead sponsor
- University of Alabama at BirminghamUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 2 Apr 2018 (actual)
- Primary completion
- 27 Apr 2023 (actual)
- Study completion
- 22 May 2025 (actual)
- First posted
- 26 Nov 2018 (actual)
- Results
- Posted 10 Jun 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this research study is to assess the efficacy of ingesting a small amount of the harmless bacterium Oxalobacter formigenes in establishing residence in the guts of healthy participants and to determine whether this influences the oxalate passed in urine.
Detailed description
Adults that are not colonized with O. formigenes, have no history of stone disease, and are in good health as judged by their medical history and a complete metabolic profile of their serum, will be recruited from within the greater Birmingham area.
Participants not colonized with O. formigenes will consume a controlled diet containing moderately high levels of oxalate (210-240 mg per day), and low levels of calcium (500 - 700 mg per day) and collect 24-hour urines to measure oxalate excretion. Following completion of urine collections, participants will ingest live O.formigenes and one week later stool will be provided to test for colonization with O.formigenes. Participants that are successfully colonized with O.formigenes will then repeat 24 hour urine collections on the same high oxalate, low calcium diet. Controlled diets will be prepared in the Metabolic Kitchen of the UAB Clinical Research Unit (CRU). Sustainability of colonization will be determined over time. Loss of colonization will be confirmed by having the subject consume an oxalate-rich meal with subsequent testing for O. formigenes.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Evaluate urinary oxalate excretion before and after colonization with the oxalate degrading bacterium Oxalobacter formigenes
| Arm | Type | Receives |
|---|---|---|
| Colonization with Oxalobacter formigenes | Experimental | Dietary Supplement: Moderately high oxalate/low calcium diet non-colonized, Dietary Supplement: Oxalobacter formigenes, Dietary Supplement: Moderately high oxalate/low calcium diet colonizedSubjects not colonized with Oxalobacter formigenes will be equilibrated to a moderately high oxalate/ low calcium oxalate controlled diet and collect 24-hour urines to measure oxalate excretion Subjects will then be colonized with Oxalobacter formigenes(Intervention). Following colonization with Oxalobacter formigenes, urinary oxalate will be measured to determine the impact of colonization on the same controlled diet |
Who may qualify
- Ages
- 19 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Good health as judged from a medical history and reported medications
- Not colonized with O. formigenes
Key exclusion criteria (3 listed)
- History of any hepatic, renal, bowel or endocrine disease or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results
- colonized with O. formigenes
- abnormal urine chemistries or blood metabolic profiles
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 |
|---|---|---|
| Moderately high oxalate/low calcium diet non-colonizedSubjects will be instructed to ingest a controlled diet moderately high in oxalate before colonization | Dietary supplement | Colonization with Oxalobacter formigenes |
| Oxalobacter formigenesSubjects will ingest live preparation of O. formigenes | Dietary supplement | Colonization with Oxalobacter formigenes |
| Moderately high oxalate/low calcium diet colonizedSubjects will be instructed to ingest a controlled diet moderately high in oxalate after colonization | Dietary supplement | Colonization with Oxalobacter formigenes |
Primary outcome
Percent Decrease in Urinary Oxalate Excretion After Colonization With O.Formigenes
Time frame: 4 days
Mean 24-hour urine oxalate excretion after colonization with O.formigenes was compared with mean 24-hour urine oxalate before colonization
1 secondary outcome
Percentage Decrease in Stool Oxalate Content After Colonization With O.Formigenes
Time frame: 4 days
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 40984794Suryavanshi M, Franklin A, Fargue S, Assimos DG, Knight J, Miller AW. Baseline abundance of oxalate-degrading bacteria determines response to Oxalobacter formigenes probiotic therapy. Gut Microbes. 2025 Dec 31;17(1):2562337. doi: 10.1080/19490976.2025.2562337. Epub 2025 Sep 23.
- Individual participant dataSharing planned: No
Related trials for Calcium Oxalate Urolithiasis
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Gut Oxalate Absorption in Calcium Oxalate Stone Disease
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O. Formigenes Colonization in Calcium Oxalate Kidney Stone Disease
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Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone Formers
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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.
John Knight, PhD principal investigator
University of Alabama at Birmingham
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Moderately high oxalate/low calcium diet non-colonized, Oxalobacter formigenes and Moderately high oxalate/low calcium diet colonized in people with Calcium Oxalate Urolithiasis, run by University of Alabama at Birmingham at 1 site 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 2 inclusion and 3 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: finished, as of the sponsor's last update on 30 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 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. 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?
Yes. Results are posted in the registry (first posted 10 Jun 2025). 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?
Percent Decrease in Urinary Oxalate Excretion After Colonization With O.Formigenes (time frame: 4 days). 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 NCT03752684, 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 30 Jan 2026.