A Single Centre Open Label Comparison of [I-123]-Ortho-Iodohippuric Acid (OIH) With [Tc-99m]-Mercaptoacetyltriglycine (MAG3) for Assessment of Renal Tubular Function

Study Overview
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Brief Summary
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Iodine-123 labelled ortho-Iodohippuric Acid ([I-123]-OIH) was used in the early 1970's as a kidney imaging agent or tracer that lights-up inside your body when scanned, but over the years its use has declined. The most commonly used tracer is Technetium-99m labelled Mercaptoacetyltriglycine ([Tc-99m]-Mertiatide or [Tc-99m]-MAG3). However, long-term shortages may threaten the supply of the radioactive substance Tc-99m in Canada and the world. As a result of such shortages, there is a need to identify other types of tracers that can be used for imaging. [I-123]-OIH may be an alternative. The purpose of this study is to examine the diagnostic performance characteristics of [I-123]-OIH in comparison to [Tc-99m]-MAG3.

Detailed Description
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This study is being conducted to compare two imaging agents (tracers): [I-123]-OIH and [Tc-99m]-MAG3 using gamma camera imaging in participants with different levels of kidney function. Gamma camera imaging is a non-invasive nuclear scan that is used to look at organs and tissues inside the body. An imaging agent or tracer is a radioactive chemical intravenously injected into your body which lights up cells, tissues and organs. The study will evaluate the safety of a single injection of [I-123]-OIH and compare the imaging results and the calculated renal function values (using blood tests) to those of [Tc-99m]-MAG3 . 90 participants are required to complete this study.

Official Title
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A Single Centre Open Label Comparison of [I-123]-Ortho-Iodohippuric Acid (OIH) With [Tc-99m]-Mercaptoacetyltriglycine (MAG3) for Assessment of Renal Tubular Function

Conditions
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Renal Function Impairment

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At least 18 years of age. Provide signed informed consent. Documented stable renal impairment with an eGFR < 60/mL/min/1.73m^2 by two eGFR measurements within 3 months that are within ± 15% of each other or healthy prospective kidney donor with an eGFR ≥ 60 mL/min/1.73m^2. Exclusion Criteria: Females who are pregnant, planning to become pregnant or are lactating. Clinically relevant abnormal findings that could, in the opinion of the investigator, interfere with the safe completion of the study. Unable, in the opinion of the clinician or investigator, to tolerate fluid intake required for radionuclide renography. Participation in any clinical trial involving an investigational product within 30 days prior to the first injection. Not using an adequate method of family planning unless the participant, or the male participant's partner, has had a hysterectomy, a tubal ligation, is postmenopausal or is not at risk of pregnancy. Unable to lie still in a supine position for at least 30 minutes. Unable to complete study procedures, including follow-up safety assessments. Medical or psychological conditions that on assessment by the principal investigator make the participant unable to complete the procedure. History of allergic reaction to iodine or iodine compounds, inclusive of iodinated x-ray contrast media. Any other conditions that may impact the participant's ability to complete the study.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy Participants<br>eGFR ≥60 ml/min/1.73m^2, healthy prospective kidney donor | |
| Moderate Renal Function Impairment<br>eGFR 30-59 ml/minute/1.73m^2 | |
| Severe Renal Function Impairment<br>eGFR <30 mL/minute/1.73m^2 | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| [I-123]-OIH Safety | Evaluate the safety of a single injection of [I-123]-OIH administered to a population of healthy prospective kidney donors and patients with stable chronic renal impairment. | Visit 3 and Follow-up Phone Call | 
| Compare kidney function using [I-123]-OIH and [Tc-99m]-MAG3 imaging | Compare results of renal plasma flow derived from [I-123]-OIH and [Tc-99m]-MAG3 gamma camera images of healthy prospective kidney donors and patients with stable chronic renal impairment. | Visit 2 and 3 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Qualitative Assessment | Compare the qualitative assessment of kidney uptake, urine excretion and image quality of [I-123]-OIH and [Tc-99m]-MAG3 in an independent read by two nuclear medicine physicians blinded to all participant clinical data. | Visit 2 and 3 | 
| Image-derived Perfusion Data | Compare results of differential perfusion(from image-derived perfusion data) of [I-123]-OIH and [Tc-99m]-MAG3. | Visits 2 and 3 | 
| eRPF | Compare results of effective renal plasma flow (eRPF), using the single sample clearance method of [I-123]-OIH and [Tc-99m]-MAG3. | Visits 2 and 3 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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imaging, renal function, I-123 OIH, Tc-99m MAG 3