Calcium Phosphate Kidney StonesNCT07465367
Methionine for CaPhos Stone
A study testing L-Methionine in people with Calcium Phosphate Kidney Stones, run by Ryan L Steinberg.
Trial summary
Some kidney stones including calcium phosphate and struvite stones form in vary alkaline urine (high pH). Currently available medication for stone prevention, namely citrate supplementation, can lead to even higher pH levels and promote stone formation. Read more about this study
- Who is it for?
- Ages 18 to 90 years
- Conditions the study is for
- Calcium Phosphate Kidney Stones
- What is being tested?
- L-Methionine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- No sites listed yet
- Study dates
- 1 Apr 2026to Apr 2027
- 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 18 to 90 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Any patient, aged 18-90 and not incarcerated, under the care of a urologist at UIHC, with a history of kidney stones with >60% calcium phosphate composition, prior 24 hour urine collection showing a urine pH of >6.1, internet access to complete REDCap surveys
Who cannot join
- Any patient over the age of 90 years old, incarcerated or with any one or multiple of the features below:
- struvite component on prior stone analysis
- bacteria with urease producing organism at time of stone removal
- history or evidence of systemic acidosis
- use of acetazolamide, topiramate, zonisamide, valproic acid
- Stage >=3 CKD (GFR<60)
Show all 15Show fewer
- Hepatic disease
- Taking thiazide diuretics or alkali and not agreeable to holding medications for the study
- Pregnancy
- History of osteoporosis
- Allergy to methionine, sulfa or sulfa-containing products
- Allergy to any food products to be provided as part of the study
- Dietary restrictions that would prevent eating the supplied food such as vegetarian, vegan, gluten free, kosher, etc.
- Bipolar Disorder
- Homocystinuria
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Assessment of L-methionine Supplementation on Urinary pH in Calcium Phosphate Stone Formers
Some kidney stones including calcium phosphate and struvite stones form in vary alkaline urine (high pH). Currently available medication for stone prevention, namely citrate supplementation, can lead to even higher pH levels and promote stone formation. Multiple prior studies have looked at ways to acidify the urine to reduce the risk of recurrent stone formation. Ascorbic acid has been evaluated but showed no reduction in urinary pH. Ammonium chloride has shown to be effective but poorly tolerated (GI upset) at higher doses and thus is not recommended. Most recently, citric acid has been investigated but demonstrated no change in pH as compared to placebo. L-methionine is an amino acid which is metabolized to sulfate and hydrogen ions by the liver, thereby conferring an acid load onto the kidney and in theory can reduce the pH. Prior studies have demonstrated effective acidification of the urine in healthy individuals and amongst struvite stone formers. The purpose of this study is to assess the ability of L-methionine to acidify the urine of calcium phosphate stone formers. The study will involved patients abiding by a short term metabolic diet. The diet consists of typical foods (some frozen, some fresh) that have been carefully balanced to match the recommended/optimal amount of calories, protein, fat, sodium and calcium for a specific body weight. After eating this diet for 2 days, patients will begin taking L-methionine. The metabolic diet will then be resumed for 2 days at the end of taking the L-methionine (both taken together). At various times of the study, urine collections will be performed to see whether the urine becomes more acidic as a result of the L-methionine. If applicable, participants will be asked to undergo drug washout, to begin after consenting. If participants are taking Thiazide diuretics including hydrochlorothiazide, Chlorthalidone, and indapamide and alkali medications including potassium citrate, sodium bicarbonate, sodium citrate, and potassium bicarbonate, they will be asked to stop taking them 5 days before Day 1 of the protocol.
- Conditions
- Calcium Phosphate Kidney Stones
- Being tested
- L-Methionine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-MethionineDietary supplement
L-Methionine supplement and metabolic diet
| Study group | Role | What they receive |
|---|---|---|
| L-Methionine | Experimental | All participants will be given L-Methionine supplements and a special metabolic diet during this protocol. Receives: Dietary Supplement: L-Methionine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Urine pH
Measured: 11 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Mar 2026
- Study start1 Apr 2026 (estimated)
- Primary completionApr 2027 (estimated)
- Study completionApr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Calcium Phosphate Kidney StonesStudies 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
- 15 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ryan L Steinberg
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Ryan L Steinberg, University of Iowa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07465367
- Sponsor's protocol ID
- 202411458
- Status last verified
- Mar 2026
- First submitted
- 6 Mar 2026
- Last updated
- 11 Mar 2026
- Results posted
- No
- Data monitoring committee
- 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 11 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of L-methionine Supplementation on Urinary pH in Calcium Phosphate Stone Formers
- ClinicalTrials.gov ID
- NCT07465367
- Acronym / sponsor ID
- 202411458
- Conditions
- Calcium Phosphate Kidney Stones
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 15 participants (estimated)
- Lead sponsor
- Ryan L SteinbergUniversity, hospital or other
- Study start
- 1 Apr 2026 (estimated)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- Apr 2027 (estimated)
- First posted
- 11 Mar 2026 (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.
Some kidney stones including calcium phosphate and struvite stones form in vary alkaline urine (high pH). Currently available medication for stone prevention, namely citrate supplementation, can lead to even higher pH levels and promote stone formation. Multiple prior studies have looked at ways to acidify the urine to reduce the risk of recurrent stone formation. Ascorbic acid has been evaluated but showed no reduction in urinary pH. Ammonium chloride has shown to be effective but poorly tolerated (GI upset) at higher doses and thus is not recommended. Most recently, citric acid has been investigated but demonstrated no change in pH as compared to placebo. L-methionine is an amino acid which is metabolized to sulfate and hydrogen ions by the liver, thereby conferring an acid load onto the kidney and in theory can reduce the pH. Prior studies have demonstrated effective acidification of the urine in healthy individuals and amongst struvite stone formers. The purpose of this study is to assess the ability of L-methionine to acidify the urine of calcium phosphate stone formers. The study will involved patients abiding by a short term metabolic diet. The diet consists of typical foods (some frozen, some fresh) that have been carefully balanced to match the recommended/optimal amount of calories, protein, fat, sodium and calcium for a specific body weight. After eating this diet for 2 days, patients will begin taking L-methionine. The metabolic diet will then be resumed for 2 days at the end of taking the L-methionine (both taken together). At various times of the study, urine collections will be performed to see whether the urine becomes more acidic as a result of the L-methionine. If applicable, participants will be asked to undergo drug washout, to begin after consenting. If participants are taking Thiazide diuretics including hydrochlorothiazide, Chlorthalidone, and indapamide and alkali medications including potassium citrate, sodium bicarbonate, sodium citrate, and potassium bicarbonate, they will be asked to stop taking them 5 days before Day 1 of the protocol.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| L-Methionine | Experimental | Dietary Supplement: L-MethionineAll participants will be given L-Methionine supplements and a special metabolic diet during this protocol. |
Who may qualify
- Ages
- 18 to 90 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Any patient, aged 18-90 and not incarcerated, under the care of a urologist at UIHC, with a history of kidney stones with >60% calcium phosphate composition, prior 24 hour urine collection showing a urine pH of >6.1, internet access to complete REDCap surveys
Key exclusion criteria (15 listed)
- Any patient over the age of 90 years old, incarcerated or with any one or multiple of the features below:
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 |
|---|---|---|
| L-MethionineL-Methionine supplement and metabolic diet | Dietary supplement | L-Methionine |
Primary outcome
Urine pH
Time frame: 11 days
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 11 Mar 2026.
- Individual participant dataSharing planned: No
Related trials for Calcium Phosphate Kidney Stones
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Hydroxycitrate: A Novel Therapy for Calcium Phosphate Urinary Stones
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Bryophyllum Pinnatum Tea as a Novel Treatment for Recurrent 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.
Questions about this trial
What is this clinical trial studying?
A study testing L-Methionine in people with Calcium Phosphate Kidney Stones, run by Ryan L Steinberg.
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 1 inclusion and 15 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: opening soon, as of the sponsor's last update on 11 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
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 Ryan Steinberg, MD ((319) 356-2421, ryan-steinberg@uiowa.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Urine pH (time frame: 11 days). 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 11 Mar 2026.