Effect of Increasing Doses of Tiopronin on Cystine Capacity in Patients With Cystinuria

NYU Langone Health

Status and phase: Completed; Phase 2

Conditions: Cystinuria

Treatments: Drug: Tiopronin

Study type: Interventional

Funder types: Other

Identifiers

NCT03663855

18-00642

Details and patient eligibility

About

The purpose of this study is to determine the minimum effective dose of the cysteine binding thiol drug (CBTD) Tiopronin on urine cystine capacity, which is a measure of cystine solubility in the urine, in patients with cystinuria to evaluate the effect of escalating doses of cystine binding thiol drugs on the cystine capacity of the urine. The overall goal will be to help guide therapy and ultimately minimize unnecessary side effects caused by larger dosages.

Cystinuria is a rare genetic disease that can lead to significant morbidity in affected patients due to the recurrent nature of the disease. This study will follow the levels of urine cystine capacity in order to help guide treatment and to use lower than usually prescribed Tiopronin doses to decrease the potential side effects while maintaining therapeutic benefit. This will increase adherence with the medications by decreasing the burden of the large number of pills that need to be taken daily.

Enrollment: 10 patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients with a confirmed laboratory diagnosis of cystinuria who meet the following criteria: (1) stone analysis demonstrating cystine as a component, or (2) increased urinary cystine excretion (>250mg/24hrs in adults).
• A medical regimen that includes Tiopronin.
• Willing to use a medically accepted form of birth control, if female and of child bearing- potential
• Ability to reliably urinate in a collection vessel and measure urine volume.
• Ability to give informed consent.
• Documentation of a stable complete blood count (CBC) and urinalysis (UA) in the six month period prior to the date of enrollment.
• Enrollment in Rare Kidney Stone Consortium (RKSC) Protocol 6401 (Cystinuria Registry)

Exclusion criteria

• Women who are pregnant, breastfeeding, or trying to become pregnant
• Patients with renal colic
• Patients who are scheduled to undergo a surgical procedure
• Inability to give informed consent

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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10 participants in 1 patient group

Cystinuria Patients

Experimental group

Treatment:

Drug: Tiopronin