Quantifying Drug Adherence and Drug Exposure to Antiretroviral Therapy (2104)

October 31, 2019 updated by: University of Colorado, Denver

Quantifying Drug Adherence and Drug Exposure to Antiretroviral Therapy.

The purpose of this study is to evaluate cumulative exposure to tenofovir diphosphate (TFV-DP) using dried blood spots (DBS) in treated HIV-infected patients who are receiving a TFV-based regimen. Using DBS will allow the investigators to assess this simple method to measure drug exposure in the clinical setting. The investigators hypothesize that TFV-DP levels will be lowest in individuals with a detectable viral load and highest in those with viral suppression.

Study Overview

Status

Completed

Conditions

Detailed Description

Antiretroviral drug exposure is directly linked to individual host factors which include age, weight, diet, and genetics. However, the main factor impacting long-term drug exposure is drug adherence. Adherence is a strong predictor of HIV treatment outcomes, but measuring adherence is difficult due to the inaccuracy of self-reporting and other commonly used monitoring methods. To date, no gold standard measure to monitor antiretroviral exposure and adherence has been applied in clinical practice. Tenofovir (TFV) and its active metabolite, tenofovir diphosphate (TFV-DP), have distinctive pharmacological characteristics that make them ideal candidates for drug adherence and exposure monitoring. The long half life (~14-17 days) of TFV-DP in red blood cells (RBC) are properties well suited for monitoring average dose exposure over time. Based on these, the investigators propose that RBC levels of TFV-DP are an accurate and precise measure of long-term drug exposure in HIV-infected individuals. In addition, the investigators aim to quantify TFV-DP in dried blood spots (DBS) as a simple method to measure drug exposure.

This is an observational, 48-week prospective study of HIV-infected individuals treated with TFV in which the investigators will compare DBS TFV-DP levels in virologically suppressed vs. non-suppressed individuals and evaluate the utility of TFV-DP in DBS to predict virologic failure and also drug toxicity. To accomplish this, the investigators will approach HIV-infected patients currently taking TFV (which is being prescribed by a primary care physician) and who present to the clinic for regular HIV care. After informed consent is obtained, the investigators will collect extra blood samples for DBS TFV-DP and obtain information on drug adherence. The investigators will also collect extra blood samples for DBS TFV-DP at each subject's subsequent visit for approximately 3 visits in a 48 week period of time.

Study Type

Observational

Enrollment (Actual)

807

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado-Anschutz Medical Campus

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

HIV-infected individuals who are taking tenofovir.

Description

Inclusion Criteria:

  • HIV-infected individual.
  • 18 years and older.
  • Taking tenofovir.
  • Blood drawn during regular clinic visit.

Exclusion Criteria:

  • Refusal to participate.
  • Pregnancy.
  • Inability to provide informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Adjusted Odds Ratio of Level of Tenofovir-diphosphate (TFV-DP) in Dried Blood Spots (DBS) Associated With Odds of HIV Viral Suppression at All Study Visits
Time Frame: Up to 48 Weeks
HIV viral load, binary cutoff at assay level of detection (<20 copies/mL vs. >= 20 copies/mL); reference group: drug concentration (TFV-DP) < 350 femtomole (fmol)/punch vs. drug concentration (TFV-DP) >= 1850 fmol/punch; adjusted odds ratio calculated using generalized estimating equations; concentration cutoffs established in prior research of healthy volunteers
Up to 48 Weeks
Adjusted Odds Ratio of Three-month Self-reported Adeherence Associated With Odds of HIV Viral Suppression at All Study Visits
Time Frame: Up to 48 Weeks
HIV viral load, binary cutoff at assay level of detection (<20 copies/mL vs. >= 20 copies/mL); reference group: three-month self-reported adherence <28.5% vs. three-month self-reported adherence 100%; adherence cutoffs established in prior research
Up to 48 Weeks
Adjusted Odds Ratio of Level of Tenofovir-diphosphate (TFV-DP) in Dried Blood Spots (DBS) Associated With Odds of HIV Viral Suppression at Next Study Visit
Time Frame: Up to 48 Weeks
HIV viral load, binary cutoff at assay level of detection (<20 copies/mL vs. >= 20 copies/mL); drug concentration (TFV-DP) <800 femtomole (fmol)/punch) vs reference group of drug concentration (TFV-DP) >= 1650 fmol/punch; adjusted odds ratio calculated using generalized estimating equations
Up to 48 Weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Colorado, Denver

Investigators

  • Principal Investigator: Jose R. Castillo-Mancilla, MD, University of Colorado - Anschutz Medical Campus

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

December 1, 2013

Primary Completion (Actual)

July 1, 2017

Study Completion (Actual)

July 1, 2017

Study Registration Dates

First Submitted

December 4, 2013

First Submitted That Met QC Criteria

December 10, 2013

First Posted (Estimate)

December 16, 2013

Study Record Updates

Last Update Posted (Actual)

November 25, 2019

Last Update Submitted That Met QC Criteria

October 31, 2019

Last Verified

October 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 13-2104

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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