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Effect of Increasing Doses of Cystine Binding Thiol Drugs on Cystine Capacity in Patients With Cystinuria

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02125721
Recruitment Status : Completed
First Posted : April 29, 2014
Last Update Posted : April 5, 2018
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Information provided by (Responsible Party):
NYU Langone Health

Brief Summary:
The purpose of this study is to evaluate the effect of escalating doses of cystine biding thiol drugs, including tiopronin and d-penicillamine, on the urinary cystine capacity, which is a measure of the amount of cystine in the urine, in patients with cystinuria. The overall goal will be to help guide therapy and ultimately minimize unnecessary side effects caused by larger doses.

Condition or disease Intervention/treatment Phase
Cystinuria Drug: CBTD 0-3 gm Phase 4

Detailed Description:

Cystinuria is a rare genetic cause of kidney stones that leads to significant morbidity due to the recurrent nature of the disease. As a result, a significant part of treatment is focused on prevention of stone formation. Current methods of prevention include increasing fluid intake, dietary modifications, alkali therapy, and cystine binding thiol drugs (CBTDs), which help increase the solubility of cystine in the urine. At present, the dosing of CBTDs is empiric, and not titrated to a specific measured effect. Our primary objective will be to measure the effect of increasing doses of CBTDs on cystine capacity. The investigators predict that higher dosages of these medications will lead to a more positive urinary cystine capacity, or the ability of urine to take up more cystine (and therefore decreased risk of stone formation). However, the dose at which increasing dosages of the medications cease to provide additional benefit is unknown. The investigators will directly measure the cystine capacity in the urine in response to increasing doses of medications to determine if there is a dose at which the maximum benefit of the drug exists.

This is a cross-over trial of escalating doses. There will be four parts to the study. In the first part, subjects will stop taking CBTDs for 7 days, and perform a 24-hour urine collection on day 7. In part 2, they will take their usual CBTD (either tiopronin or d-penicillamine) 1 gram per day for 7 days. They will perform another 24-hour urine collection on day 7 of this study period. In part 3, they will take their usual CBTD at 2 grams per day for 7 days and in part 4 they will take their CBTD at 3 grams per day for 7 days. Again, they will perform 24-hour urine collections on day 7 of each period. The order in which the parts of the study are performed will be randomized for each subject. The mean cystine capacities in each part of the study will be compared to determine the effect of drug dosage on urinary cystine capacity.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 10 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effect of Increasing Doses of Cystine Binding Thiol Drugs on Cystine Capacity in Patients With Cystinuria
Study Start Date : June 2012
Actual Primary Completion Date : December 2017
Actual Study Completion Date : December 2017

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Increasing doses of CBTD
Intervention: CBTD 0-3 gm
Drug: CBTD 0-3 gm
Oral CBTD 0-3 gm dose/day for 7 days, dose escalation
Other Name: Thiola or tiopronin; d-penicillamine

Primary Outcome Measures :
  1. Cystine capacity [ Time Frame: 4 weeks on assigned therapy ]
    We will test for a negative correlation between progressive increases in doses of thiol drugs and cystine capacity

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Be a patient with a confirmed diagnosis of cystinuria.
  • Be already taking a CBTD (either D-penicillamine (Cuprimine®) or tiopronin (Thiola®) as part of your medication regimen.
  • Be between 18 and 80 years of age
  • Be enrolled in the Cystinuria Registry.

Exclusion Criteria:

  • You are not a patient with cystinuria
  • You are not already taking a cystine binding thiol drug
  • You have renal colic (if you are passing a stone)
  • You are scheduled to undergo a urologic procedure
  • You are unwilling or unable to provide informed consent in order to be able to participate.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02125721

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United States, New York
NYU Langone Medical Center
New York, New York, United States, 10016
Sponsors and Collaborators
NYU Langone Health
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Principal Investigator: David S Goldfarb, MD NYU Langone Medical Center
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Responsible Party: NYU Langone Health Identifier: NCT02125721    
Other Study ID Numbers: 16-00108
1U54DK083908 ( U.S. NIH Grant/Contract )
First Posted: April 29, 2014    Key Record Dates
Last Update Posted: April 5, 2018
Last Verified: April 2018

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by NYU Langone Health:
D-penicillamine (Cuprimine®)
tiopronin (Thiola®)
Additional relevant MeSH terms:
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Renal Aminoacidurias
Renal Tubular Transport, Inborn Errors
Kidney Diseases
Urologic Diseases
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases
Protective Agents
Physiological Effects of Drugs
Chelating Agents
Sequestering Agents
Molecular Mechanisms of Pharmacological Action
Antirheumatic Agents