CystinuriaPhase 2NCT04818034
The Effect of Sodium-glucose Cotransporter (SGLT) 2 Inhibitors on Cystine Stone Formation: A Preliminary Study
A Phase 2 study testing Dapagliflozin in people with Cystinuria, run by University of California, San Francisco at 1 site in United States.
Trial summary
Cystinuria is an inherited autosomal recessive disorder of the kidney that is the result of an inability to reabsorb cystine from the urine. Supersaturation of cystine in the urine produces crystals that precipitate and form stones in the kidney, which can be a cause of obstruction, infection, and chronic kidney… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cystinuria
- What is being tested?
- Dapagliflozin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Aug 2021to 28 Apr 2022
- Phase
- Phase 2
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- males and females age 18 or older
- documented cystinuria on prior 24-hour urine collection and/or stone analysis
- history of previous cystine kidney stones
- able and willing to provide consent
Who cannot join
- prior diagnosis of diabetes mellitus (type I or type II)
- current SGLT-2 inhibitor administration at the time of screening
- SGLT-2 inhibitor administration within the last year prior to screening
- vulnerable populations including incarceration status
- anticipation of pregnancy during the study duration
- unable to give informed consent
Show all 9Show fewer
- non-English primary language
- pregnancy, lactation, or child- bearing age without birth control devices
- serious illness likely to cause death within the next 5 years.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of California, San Francisco
San Francisco, California, 94143
About this study
Cystinuria is an inherited autosomal recessive disorder of the kidney that is the result of an inability to reabsorb cystine from the urine. Supersaturation of cystine in the urine produces crystals that precipitate and form stones in the kidney, which can be a cause of obstruction, infection, and chronic kidney disease. Cystine stones constitute a major health challenge for affected individuals with cystinuria because of the frequent recurrence of painful symptoms and the current absence of effective, patient-accepting treatment.
A mainstay of therapy is breaking or preventing the cystine bond on the molecular level such that cystine (which is formed from the joining of two cysteine amino acids and their corresponding sulfur atoms) cannot precipitate in the urine. It is hypothesized that a glucose molecule may be able to do this if introduced into the urine. SGLT-2 inhibitors are a class of drug that are FDA approved to treat diabetes mellitus (DM) and heart failure by inhibiting an enzyme in the kidney that allows for reabsorption of glucose from the urine. This effectively increases the concentration of glucose in the urine. Our hypothesis suggests that administration of this drug to patients with cystine will introduce sufficient glucose into the urine to prevent the formation of cystine stones. To date, there has been no published data on the effectiveness of this therapy for this indication, although the dosage and administration would be identical to that already approved by the FDA for the treatment of DM and heart failure.
Read the detailed description
This is a single center, proof of concept prospective cohort trial designed to assess the effect of daily oral administration of dapagliflozin on cystine formation in freshly voided urine. Five subjects are planned, each with previously diagnosed cystinuria and without current treatment except with potassium citrate medication.
Total duration of subject participation with be up to four weeks. Total duration of the study is expected to be 6 months.
- Conditions
- Cystinuria
- Being tested
- Dapagliflozin
- Medical subject headings
- Cystinuria
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DapagliflozinDrug
Also called FARXIGA
Dapagliflozin is to lower blood sugar levels in adults with type 2 diabetes.
| Study group | Role | What they receive |
|---|---|---|
| 10 mg Dapagliflozin taken orally once daily for 4 weeks | Experimental | 10 mg of the study drug Dapagliflozin taken orally once daily for 4 weeks Receives: Drug: Dapagliflozin |
What is being measured
The primary outcome is the main question the study is designed to answer.
24hr Urine Measurements of the Effect of SGLT-2 Inhibitor Therapy on Cystine Production in Urine in Patients With Cystinuria
The primary efficacy endpoint will be assessed by comparing previous 24hr urine cystine concentration data collected prior to study participation and 24hr urine concentration data collected after being on the study drug, specifically examining the content of cystine in the urine but not exclusively.
Measured: 1 month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Mar 2021
- Study start30 Aug 2021
- Primary completion13 Dec 2021
- Study completion28 Apr 2022
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.
- Other trials for CystinuriaStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe 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 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Marshall Stoller, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04818034
- Sponsor's protocol ID
- SGLT2
- Status last verified
- Oct 2025
- First submitted
- 17 Mar 2021
- Last updated
- 16 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Sodium-glucose Cotransporter (SGLT) 2 Inhibitors on Cystine Stone Formation: A Preliminary Study
- ClinicalTrials.gov ID
- NCT04818034
- Acronym / sponsor ID
- SGLT2
- Conditions
- Cystinuria
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Study start
- 30 Aug 2021 (actual)
- Primary completion
- 13 Dec 2021 (actual)
- Study completion
- 28 Apr 2022 (actual)
- First posted
- 26 Mar 2021 (actual)
- Results
- Posted 8 Oct 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Cystinuria is an inherited autosomal recessive disorder of the kidney that is the result of an inability to reabsorb cystine from the urine. Supersaturation of cystine in the urine produces crystals that precipitate and form stones in the kidney, which can be a cause of obstruction, infection, and chronic kidney disease. Cystine stones constitute a major health challenge for affected individuals with cystinuria because of the frequent recurrence of painful symptoms and the current absence of effective, patient-accepting treatment.
A mainstay of therapy is breaking or preventing the cystine bond on the molecular level such that cystine (which is formed from the joining of two cysteine amino acids and their corresponding sulfur atoms) cannot precipitate in the urine. It is hypothesized that a glucose molecule may be able to do this if introduced into the urine. SGLT-2 inhibitors are a class of drug that are FDA approved to treat diabetes mellitus (DM) and heart failure by inhibiting an enzyme in the kidney that allows for reabsorption of glucose from the urine. This effectively increases the concentration of glucose in the urine. Our hypothesis suggests that administration of this drug to patients with cystine will introduce sufficient glucose into the urine to prevent the formation of cystine stones. To date, there has been no published data on the effectiveness of this therapy for this indication, although the dosage and administration would be identical to that already approved by the FDA for the treatment of DM and heart failure.
Detailed description
This is a single center, proof of concept prospective cohort trial designed to assess the effect of daily oral administration of dapagliflozin on cystine formation in freshly voided urine. Five subjects are planned, each with previously diagnosed cystinuria and without current treatment except with potassium citrate medication.
Total duration of subject participation with be up to four weeks. Total duration of the study is expected to be 6 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 10 mg Dapagliflozin taken orally once daily for 4 weeks | Experimental | Drug: Dapagliflozin10 mg of the study drug Dapagliflozin taken orally once daily for 4 weeks |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- males and females age 18 or older
- documented cystinuria on prior 24-hour urine collection and/or stone analysis
- history of previous cystine kidney stones
- able and willing to provide consent
Key exclusion criteria (9 listed)
- prior diagnosis of diabetes mellitus (type I or type II)
- current SGLT-2 inhibitor administration at the time of screening
- SGLT-2 inhibitor administration within the last year prior to screening
- vulnerable populations including incarceration status
- anticipation of pregnancy during the study duration
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 |
|---|---|---|
| DapagliflozinAlso: FARXIGADapagliflozin is to lower blood sugar levels in adults with type 2 diabetes. | Drug | 10 mg Dapagliflozin taken orally once daily for 4 weeks |
Primary outcome
24hr Urine Measurements of the Effect of SGLT-2 Inhibitor Therapy on Cystine Production in Urine in Patients With Cystinuria
Time frame: 1 month
The primary efficacy endpoint will be assessed by comparing previous 24hr urine cystine concentration data collected prior to study participation and 24hr urine concentration data collected after being on the study drug, specifically examining the content of cystine in the urine but not exclusively.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- 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. This study is not recruiting at the moment.
Marshall Stoller principal investigator
University of California, San Francisco
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Dapagliflozin in people with Cystinuria, run by University of California, San Francisco 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 4 inclusion and 9 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 16 Oct 2025. 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.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 8 Oct 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?
24hr Urine Measurements of the Effect of SGLT-2 Inhibitor Therapy on Cystine Production in Urine in Patients With Cystinuria (time frame: 1 month). 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 16 Oct 2025.