The Effect of Sodium-glucose Cotransporter (SGLT) 2 Inhibitors on Cystine Stone Formation: A Preliminary 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.

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Key information

Conditions

Cystinuria Congenital, Hereditary, and Neonatal Diseases and Abnormalities Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Genetic Diseases, Inborn Kidney Diseases Male Urogenital Diseases Renal Aminoacidurias Renal Tubular Transport, Inborn Errors Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

University of California, San Francisco

San Francisco, California, 94143, United States

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

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
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.

Treatment and study plan

Dapagliflozin

Drug

Dapagliflozin is to lower blood sugar levels in adults with type 2 diabetes.

Other names: FARXIGA

Primary outcomes

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.

Sponsors and collaborators

Lead sponsor

University of California, San Francisco

Other

Registry information

Important dates

Study start: 2021
Primary completion: 2021
Study completion: 2022
First posted: Mar 26, 2021
Registry last updated: Oct 16, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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