O. Formigenes Colonization in Calcium Oxalate Kidney Stone Disease

Not Applicable

Recruiting

• Conditions: Urolithiasis; Nephrolithiasis, Calcium Oxalate; Urolithiasis, Calcium Oxalate; Nephrolithiasis; Kidney Calculi; Kidney Stone; Oxalate Urolithiasis; Oxaluria
• Interventions: Dietary Supplement: Low oxalate fixed diets pre-colonization; Dietary Supplement: Moderately high oxalate fixed diets pre-colonization; Dietary Supplement: Colonization with Oxalobacter formigenes; Dietary Supplement: Low oxalate fixed diets post-colonization; Dietary Supplement: Moderately high oxalate fixed diets post-colonization

• Registration Number: NCT06330246
• Lead Sponsor: University of Alabama at Birmingham

Brief Summary

The goal of this trial is to test if colonization with the gut bacteria Oxalobacter formigenes leads to a reduction in urinary oxalate excretion in patients with calcium oxalate kidney stone disease.

The study will recruit adult participants with a history of calcium oxalate kidney stones who are not colonized with Oxalobacter formigenes.

Participants will

* ingest fixed diets containing low and moderately high amounts of oxalate for 4 days at a time

* collect urine, blood and stool samples during the fixed diets

* ingest a preparation of live Oxalobacter formigenes to induce colonization with Oxalobacter formigenes

Detailed Description

In this study the investigators propose to measure the excretion of urinary oxalate on a fixed diet with controlled amounts of oxalate, before and after inducing colonization with the gut bacteria Oxalobacter formigenes in individuals with a history of calcium oxalate kidney stones not already colonized with Oxalobacter formigenes.

Screening and Pre-colonization phase. Between the University of Alabama at Birmingham (UAB) and the University of Texas Southwestern Medical Center (UTSW), the study will enroll 40 individuals with a history of idiopathic calcium oxalate kidney (20 males/20 females). Screening will include stool colonization testing, blood complete metabolic profile, 24-hr urine specimens collected at home on self-selected diets and anthropometric measurements.

Participants will ingest a low-oxalate (\<60 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning.

After a wash-out period of at least 1 week, participants will ingest a moderately high-oxalate (250-300 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning.

Colonization and Post-colonization phase. Participants will be colonized with Oxalobacter formigenes by ingesting a freshly thawed paste of live bacterial preparation of O. formigenes. They will collect a stool sample 1 week later to assess if colonization occured.

After confirmation of successful colonization, participants will ingest a low-oxalate (\<60 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning.

After a wash-out period of at least 1 week, participants will ingest a moderately high-oxalate (250-300 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning.

Follow-up phase Participants will be followed up every 6 months to assess sustainability of colonization, provide a stool sample and answer a simple questionnaire. A 24-hr urine collection will be requested once a year after colonization, on the same moderately high oxalate diet diet after 2 days of dietary equilibration.

Study Timeline

• Study First Submitted: 2024-03-19
• Study First Submitted QC: 2024-03-19
• Study First Posted: 2024-03-26
• Study Start: 2024-04-17
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-09
• Last Update Posted: 2025-05-13
• Primary Completion: 2030-12-31
• Study Completion: 2031-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
colonization with Oxalobacter formigenes	Low oxalate fixed diets pre-colonization	Colonization with a live preparation of Oxalobacter formigenes, strain OxCC13.
colonization with Oxalobacter formigenes	Low oxalate fixed diets post-colonization	Colonization with a live preparation of Oxalobacter formigenes, strain OxCC13.
colonization with Oxalobacter formigenes	Moderately high oxalate fixed diets pre-colonization	Colonization with a live preparation of Oxalobacter formigenes, strain OxCC13.
colonization with Oxalobacter formigenes	Colonization with Oxalobacter formigenes	Colonization with a live preparation of Oxalobacter formigenes, strain OxCC13.
colonization with Oxalobacter formigenes	Moderately high oxalate fixed diets post-colonization	Colonization with a live preparation of Oxalobacter formigenes, strain OxCC13.

Primary Outcome Measures

Name	Time	Method
Change in urinary oxalate excretion following colonization with Oxalobacter formigenes	2 months	Difference between urinary oxalate excretion on the moderately high oxalate diet pre-colonization and urinary oxalate excretion on the moderately high oxalate diet post-colonization

Secondary Outcome Measures

Name	Time	Method
Sustainability of colonization with Oxalobacter formigenes	4 years	duration of colonization after successful induction of colonization sith Oxalobacter formigenes

Trial Locations

Locations (2)

UTSW; 🇺🇸 Dallas, Texas, United States

University of Alabama at Birmingham; 🇺🇸 Birmingham, Alabama, United States