Renal Effects of Hormones/Biomarkers in Transgender PrEP Recipients

Study Overview
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Brief Summary
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Will use a subset of the main study cohort of transgender or non-binary individuals to evaluate the relationships between self-reported exogenous hormone use, endogenous hormone values, renal biomarkers, drug levels and directly measured renal function.

Detailed Description
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This cross-sectional sub-study will use a subset of the main study cohort of transgender (TG) or non-binary (NB) individuals to evaluate the relationships between self-reported exogenous hormone use, endogenous hormone values (serum estradiol, estrone, free/total testosterone), renal biomarkers, drug levels (measured by tenofovir diphosphate, TFV-DP, and emtricitabine triphosphate, FTC-TP, on dried blood spot cards and urine) and directly measured renal function (iohexol clearance).

Official Title
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Renal Effects of Hormones/Biomarkers in Transgender PrEP Recipients Sub-Study

Conditions
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Transgender, Renal Function, Hormone Replacement Therapy

Intervention / Treatment
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* Diagnostic Test: IHX-CL measurements
* Drug: Iohexol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: HIV-uninfected Identifying as transgender or nonbinary (TG/NB) Age ≥ 18 years (adult) At risk of acquiring HIV Calculated creatinine clearance (CRCL) ≥ 60 mL/minute Taking emtricitabine/tenofovir alafenamide Willing to receive a small dose of iohexol Willing to provide 30 mL blood and a urine sample Exclusion Criteria: Allergy to iohexol Use of concurrent medications that may interfere with iohexol such as metformin, amiodarone or beta-blockers Anuric or unable to produce 30 mL of urine Other condition that, in the opinion of the investigator, would put the participant at risk, complicate interpretation of study outcome data, or would otherwise interfere with participation or achieving the study objectives

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: iohexol
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Iohexol injection<br>The research pharmacist will prepare the iohexol injection in a 1cc tuberculin syringe, consisting of 0.5cc sterile water for injection (SWFI) and 0.5cc iohexol (Omnipaque 300). The study coordinator/personnel (licensed RN) will inject the iohexol dose into the subcutaneous tissue on the opposite arm used for blood sampling; the time will be recorded. The participant will be monitored for adverse events 30 minutes post iohexol administration at the AVRC. If the participant has not had any adverse event within 30 minutes, they will be asked to leave the AVRC and return within 2 hours and 55 minutes post Iohexol injection for lab collection. | Diagnostic Test: IHX-CL measurements<br>* The distribution of measured IHX-CL values and other continuous variables will be assessed to ensure a parametric distribution.<br>* Other names: Iohexol;Drug: Iohexol<br>* Iohexol clearance measurement<br>* Other names: OMNIPAQUE;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Iohexol clearance | Rate of clearance (mL/min) of iohexol from the body after a small dose is administered subcutaneously. Iohexol clearance is the gold standard for measuring kidney function. | Day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood concentration of tenofovir | Tenofovir concentrations in blood and blotted on dried blood spot cards. | Day 1 |