A Phase 2 interventional study of Dapagliflozin in Cystinuria, sponsored by University of California, San Francisco. Completed at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-10-16.
Sponsored by University of California, San Francisco · Phase 2, Interventional, and Treatment
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.
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.
21 studies on the registry are indexed under Cystinuria; 5 are open to participants now.
Browse Cystinuria studies →University of California, San Francisco is the lead sponsor of 2,169 studies on the registry; 372 are open to participants now.
Of its 267 completed or terminated interventional studies of FDA-regulated products, 202 (76%) have results posted.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
10 mg of the study drug Dapagliflozin taken orally once daily for 4 weeks
Drug: Dapagliflozin
Dapagliflozin is to lower blood sugar levels in adults with type 2 diabetes.
Also known as: FARXIGA
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.
Time frame: 1 month
The study team will identify the patients being treated for cystinuria within the study team's clinic. The study team will inform these patients of the study and provide them with the study details to allow further discussion and to answer any questions the patients might have.
| Milestone | Study Drug |
|---|---|
| Started | 10 |
| Completed | 10 |
| Not completed | 0 |
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.
| 24hr urine cystine concentration (mg) | Study Drug |
|---|---|
| 24hr Urine Measurements of the Effect of SGLT-2 Inhibitor Therapy on Cystine Production in Urine in Patients With Cystinuria | 999.3 ± 1.1 |
Collected over From enrollment until the end of follow-up, 4 weeks.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Study Drug | 0/10 (0%) | 0/10 (0%) | 0/10 (0%) |
| Age, Categorical(Participants) | Study Drug |
|---|---|
| <=18 years | 0 |
| Between 18 and 65 years | 10 |
| >=65 years | 0 |
| Sex: Female, Male(Participants) | Study Drug |
|---|---|
| Female | 7 |
| Male | 3 |
| Race (NIH/OMB)(Participants) | Study Drug |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 0 |
| White | 9 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Ethnicity (NIH/OMB)(Participants) | Study Drug |
|---|---|
| Hispanic or Latino | 3 |
| Not Hispanic or Latino | 7 |
| Unknown or Not Reported | 0 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Aug 2021 to primary completion in Dec 2021, 3 months.
Results were first posted in Oct 2025, 3 years 9 months after primary completion.
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Studies of the drug tested here: Dapagliflozin
University of California, San Francisco →