Plasma Tenofovir Levels to Support Adherence to TDF/FTC Preexposure Prophylaxis for HIV Prevention in MSM in Los Angeles, California

Abstract

BACKGROUND TDF/FTC PrEP is effective against rectal HIV acquisition when taken as prescribed. Strategies that identify and intervene with those challenged by adherence to daily medication are needed. SETTING PATH-PrEP was an open-label single arm interventional cohort study conducted at 2 community-based clinical sites in Los Angeles, California. METHODS We enrolled self-identified MSM and TGW ≥18 years of age at elevated risk of HIV acquisition. Participants received a PEP or PrEP-based HIV prevention package for at least 48 weeks. Plasma TFV levels from each PrEP visit assessed as below the limit of quantiatation (<10 ng/mL) triggered increased adherence support. RESULTS 301 participants enrolled. Forty-eight-week retention in the PrEP cohort was 75.1%. Biomarker evidence of PrEP adherence consistent with ≥4 doses per week at weeks 4, 12, 24, 36, and 48 were found in 83.1%, 83.4%, 75.7%, 71.6%, and 65.5% of participants; younger and African-American participants were less likely to have protective drug levels. Most of those with suboptimal adherence had adherence improvement after brief intervention. One seroconversion occurred in a participant who discontinued PrEP. Nearly half (46.4%) of participants were diagnosed with at least one incident STI during 48 weeks of study follow-up. CONCLUSIONS AND RELEVANCE PrEP was acceptable and well tolerated in a diverse population of MSM in Los Angeles. A brief intervention triggered from biomarkers of poor adherence was associated with improved adherence. Drug level monitoring has the potential to allow targeting of additional adherence support to those struggling with daily tablet adherence.

Patterns and clinical consequences of discontinuing HIV preexposure prophylaxis during primary care

“…We found that PrEP discontinuations were more likely to occur among persons who were younger, who identified as transgender women, and who had multiple mental health disorders. Our findings corroborates prior studies that have found an association between younger age and challenges accessing or continuing with PrEP [14,30,31] and highlights additional sub-populations, including transgender women and those with mental health disorders, for whom intensive and/or tailored support for continued PrEP use may be beneficial. Because HIV incidence rates among young MSM and transgender women are among the highest in any sub-population nationally [32], and because mental health diagnoses have been associated with HIV risk behaviours [33,34], addressing ineffective PrEP use in these groups should be prioritized.…”

LC–MS/MS method for the simultaneous determination of tenofovir, emtricitabine, elvitegravir and rilpivirine in dried blood spots

“…To evaluate patient adherence, therapeutic drug monitoring from patients has been advocated to determine the concentration of drug in systemic circulation (Landovitz et al, 2017). Human trials of antiretroviral drugs for HIV treatment in low-income zones like West Africa has demonstrated good efficacy and concluded that a dried blood spot (DBS) method might improve the assessment of ART failure (de Truchis et al, 2016).…”

“…Adherence to treatment is one of the major issues with antiretroviral therapy (ART). To evaluate patient adherence, therapeutic drug monitoring from patients has been advocated to determine the concentration of drug in systemic circulation (Landovitz et al, 2017).…”

Pharmacologic‐Based Methods of Adherence Assessment in HIV Prevention

“…Although a single, universal adherence measure would ease coordination of adherence assessments across research trials and clinical practice, the ability to use and integrate methods into study designs and clinical practice will vary by geographic region and setting. Early studies suggest improved adherence with drug concentration feedback, but more research is needed. Patient preference for certain methods and willingness to provide samples will need to be understood, and how to communicate adherence interpretations between providers and patients requires more study.…”