Long Term Clinical Efficacy of Sodium-glucose Cotransporter-2 (SGLT-2) Inhibitor in Cystinurics

This is a single center, prospective cohort trial designed to assess the effect of daily oral administration of dapagliflozin 10 mg on cystine stone formation across routine imaging obtained during management of this disease. 25 subjects are planned, each with previously diagnosed cystinuria and without current treatment except with potassium citrate medication. Each patient identified in the clinic as a potential participant will be screened to determine subject eligibility. Subjects who meet all inclusion criteria and none of the exclusion criteria will be entered into the study. Consent will be obtained. The therapy under investigation, dapagliflozin 10 mg, will then be administered orally to each participant daily for one year. Each subject will be contacted 1 week by the study team after treatment begins to check compliance, tolerability, and side effects with SGLT-2 inhibitor therapy. Each subject will then be contacted every 8 weeks by the study team for follow-up and to continue checks on compliance, tolerability, and side effects with SGLT-2 inhibitor therapy. Each subject will subsequently undergo routine care with no further alterations or interruptions to their typical care with routine follow up appointments with a study doctor every 3-4 months. Routine standard-of-care surveillance imaging for their cystinuria and formation of cystine stones will also occur as part of the treatment and management of each participant's kidney stone disease. This routine care will continue to be performed during the study period, the only difference being the collection of data with regard to ongoing stone burden for the cystinuria patients receiving treatment with daily oral dapagliflozin 10 mg on each routine imaging scan. Tolerability of the study therapy will be assessed at each routine visit during the participant's usual care. Participants who require operative intervention for their kidney stones during the treatment period will be removed from the study. No placebo will be used during this study. Total duration of subject participation with be up to 1 year and 3 months. Total duration of the study is expected to be up to 1 year and 3 months.