Adherence and Clinical Correlates in Persons With HIV on TAF

This is an observational, 48-week, prospective study of PWH treated with TAF in which the investigators will compare TFV-DP concentrations in DBS in virologically suppressed vs. non-suppressed individuals and evaluate the utility of TFV-DP in DBS to predict future viremia. To accomplish this, the investigators will approach PWH currently taking TAF (which is being prescribed by a primary care physician) and who present to the clinic for regular HIV care and HIV VL assessment. Participants will complete up to 3 visits (at least 2 weeks apart) during the 48-week study follow-up period.

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Key information

Conditions

HIV Acquired Immunodeficiency Syndrome Blood-Borne Infections Communicable Diseases Genital Diseases HIV Infections Immune System Diseases Immunologic Deficiency Syndromes Infections Lentivirus Infections RNA Virus Infections Retroviridae Infections Sexually Transmitted Diseases Sexually Transmitted Diseases, Viral Slow Virus Diseases Urogenital Diseases Virus Diseases

Age range

18 year–89 year

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Colorado Health

Aurora, Colorado, 80045, United States

About this study

Antiretroviral (ARV) drug exposure is directly linked to individual host factors, including age, weight, diet, and genetics. However, the main factor influencing 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. There is no gold-standard measure to monitor ARV exposure and adherence that has been implemented in clinical practice. Tenofovir diphosphate (TFV-DP), the phosphorylated anabolite of tenofovir (TFV), has distinct pharmacological characteristics that make it an ideal candidate for drug adherence and exposure monitoring. The long half-life of TFV-DP (~17 days) in red blood cells (RBC), which are abundant in dried blood spots (DBS) are properties that make it well suited for monitoring average TFV exposure over time both from tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). TFV-DP in DBS in persons with HIV (PWH) on TDF has been associated with viral suppression and is predictive of future viremia, even in patient who are virologically-suppressed. However, data on TFV-DP in DBS from TAF are lacking. To address this gap, this study will assess the association of TFV-DP in DBS from PWH on TAF with clinically-relevant virologic outcomes.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Females or males with HIV (≥18 years), able to give informed consent and comply with study procedures who are having a blood draw as part of their regular clinical care.
Being prescribed TAF-based ART >= 3 months.

Exclusion criteria

For females, active pregnancy or intent to become pregnant.

Treatment and study plan

Primary outcomes

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: 48 weeks

HIV viral load, binary cutoff at assay level of detection (<20 copies/mL vs >= 20 copies/mL); reference group lowest adherence category for TFV-DP; adjusted odds ratio calculated using generalized estimated equations; concentration cutoffs established in prior research of healthy volunteers and persons with HIV (PWH)
Adjusted Odds Ratio of Level of Tenofovir-diphosphate (TFV-DP) in Dried Blood Spots (DBS) Associated with odds of HIV viremia at next study visit

Time frame: 48 weeks

HIV viral load, binary cutoff at assay level of detection (<20 copies/mL vs >= 20 copies/mL); reference group lowest adherence category for TFV-DP; adjusted odds ratio calculated using generalized estimated equations; concentration cutoffs established in prior research of healthy volunteers and persons with HIV (PWH)

Sponsors and collaborators

Lead sponsor

University of Colorado, Denver

Other

Registry information

Acronym: ACT

Important dates

Study start: 2022
Primary completion: 2026
Study completion: 2026
First posted: Apr 19, 2022
Registry last updated: May 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed