"It Was Not My Aim to Sleep There": The Impact of Timing and Location of Sex on Adherence to Coitally-Dependent HIV Pre-exposure Prophylaxis

A phase I study to assess safety, pharmacokinetics, and pharmacodynamics of a vaginal insert containing tenofovir alafenamide and elvitegravir

Background

New multi-purpose prevention technology (MPT) products are needed to prevent human immunodeficiency virus (HIV) and herpes simplex virus type 2 (HSV2). In this study, we evaluated a fast-dissolve insert that may be used vaginally or rectally for prevention of infection.

Objective

To describe the safety, acceptability, multi-compartment pharmacokinetics (PK), and in vitro modeled pharmacodynamics (PD) after a single vaginal dose of an insert containing tenofovir alafenamide (TAF) and elvitegravir (EVG) in healthy women.

Methods

This was a Phase I, open-label, study. Women (n=16) applied one TAF (20mg)/EVG (16mg) vaginal insert and were randomized (1:1) to sample collection time groups for up to 7 days post dosing. Safety was assessed by treatment-emergent adverse events (TEAEs). EVG, TAF and tenofovir (TFV) concentrations were measured in plasma, vaginal fluid and tissue, and TFV-diphosphate (TFV-DP) concentration in vaginal tissue. PD was modeled in vitro by quantifying the change in inhibitory activity of vaginal fluid and vaginal tissue against HIV and HSV2 from baseline to after treatment. Acceptability data was collected by a quantitative survey at baseline and post treatment.

Results

The TAF/EVG insert was safe, with all TEAEs graded as mild, and acceptable to participants. Systemic plasma exposure was low, consistent with topical delivery, while high mucosal levels were detected, with median TFV vaginal fluid concentrations exceeding 200,000 ng/mL and 1,000 ng/mL for up to 24 hours and 7 days post dosing, respectively. All participants had vaginal tissue EVG concentrations of > 1 ng/mg at 4 and 24 hours post dosing. The majority had tissue TFV-DP concentrations exceeding 1000 fmol/mg by 24 - 72 hours post dosing. Vaginal fluid inhibition of HIV-1 and HSV-2 in vitro significantly increased from baseline and was similarly high at 4 and 24 hours post dosing. Consistent with high tissue TFV-DP concentrations, p24 HIV antigen production from ectocervical tissues infected ex vivo with HIV-1 significantly decreased from baseline at 4 hours post dosing. HSV-2 production from tissue also decreased post treatment.

Conclusions

A single dose of TAF/EVG inserts met PK benchmarks, with PK data supporting an extended window of high mucosal protection. PD modeling supports mucosal protection against both HIV-1 and HSV-2. The inserts were safe and highly acceptable.

Clinical trial registration

ClinicalTrials.gov, identifier NCT03762772.

Impact of Women's Home Environment on Use of the Dapivirine Vaginal Ring for HIV Prevention in Sub-Saharan Africa

The monthly dapivirine vaginal ring has proven efficacious in reducing HIV incidence in two Phase 3 clinical trials. When considering the potential future availability of the ring to the public, key questions remain about the feasibility of integrating the ring as an HIV prevention intervention into women's lives. We conducted qualitative mapping interviews (n = 66) among women enrolled in MTN-025/HOPE, an open-label trial conducted in Malawi, South Africa, Uganda and Zimbabwe, to examine how home environments influenced use of the dapivirine vaginal ring. Most women had secure places to store their rings including wardrobes, suitcases, and bags. The primary concerns for ring storage were potential tampering from children or rodents. Household overcrowding limited the privacy some women had which made removal and insertion of vaginal rings challenging. Despite these challenges, ring storage, insertion, and removal was feasible across social and living contexts.

Adolescent girls and young women's PrEP-user journey during an implementation science study in South Africa and Kenya

Successful scale-up of PrEP for HIV prevention in African adolescent girls and young women (AGYW) requires integration of PrEP into young women's everyday lives. We conducted interviews and focus group discussions with 137 AGYW PrEP users aged 16-25 from South Africa and Kenya. Individual and relational enablers and disablers were explored at key moments during their PrEP-user journey from awareness, initiation and early use through persistence, including PrEP pauses, restarts, and discontinuation. PrEP uptake was facilitated when offered as part of an integrated sexual reproductive health service, but hampered by low awareness, stigma and misconceptions about PrEP in the community. Daily pill-taking was challenging for AGYW due to individual, relational and structural factors and PrEP interruptions (intended or unintended) were described as part of AGYW's PrEP-user journey. Disclosure, social support, adolescent-friendly health counseling, and convenient access to PrEP were reported as key enablers for PrEP persistence.

Facilitating engagement with PrEP and other HIV prevention technologies through practice-based combination prevention

INTRODUCTION

Recent years have witnessed a rapid expansion of efficacious biomedical HIV prevention technologies. Promising as they may be, they are largely delivered through standard, clinic-based models, often in isolation from structural and behavioural interventions. This contributes to varied, and often poor, uptake and adherence. There is a critical need to develop analytical tools that can advance our understandings and responses to the combination of interventions that affect engagement with HIV prevention technologies. This commentary makes a call for practice-based combination HIV prevention analysis and action, and presents a tool to facilitate this challenging but crucial endeavour.

DISCUSSION

Models and frameworks for combination HIV prevention already exist, but the process of identifying precisely what multi-level factors that need to be considered as part of a combination of HIV interventions for particular populations and settings is unclear. Drawing on contemporary social practice theory, this paper develops a "table of questioning" to help interrogate the chain and combination of multi-level factors that shape engagement with HIV prevention technologies. The tool also supports an examination of other shared social practices, which at different levels, and in different ways, affect engagement with HIV prevention technologies. It facilitates an analysis of the range of factors and social practices that need to be synchronized in order to establish engagement with HIV prevention technologies as a possible and desirable thing to do. Such analysis can help uncover local hitherto un-identified issues and provide a platform for novel synergistic approaches for action that are not otherwise obvious. The tool is discussed in relation to PrEP among adolescent girls and young women in sub-Saharan Africa.

CONCLUSIONS

By treating engagement with HIV prevention technologies as a social practice and site of analysis and public health action, HIV prevention service planners and evaluators can identify and respond to the combination of factors and social practices that interact to form the context that supports or prohibits engagement with HIV prevention technologies for particular populations.

HIV pre-exposure prophylaxis for adolescent girls and young women in Africa: from efficacy trials to delivery

INTRODUCTION

Adolescent girls and young women (AGYW) in Africa have high HIV incidence despite scale-up of HIV testing and HIV treatment. Placebo-controlled trials of tenofovir-based pre-exposure prophylaxi (PrEP) in diverse populations demonstrated that PrEP works with close to 100% effectiveness if taken with high, but not perfect, adherence. Divergent efficacy estimates among African AGYW led to demonstration and implementation projects to better understand motivations for HIV prevention, uptake, adherence and persistence to PrEP. To inform PrEP programmes, the design and initial findings from PrEP demonstration projects for AGYW are reviewed.

DISCUSSION

Early lessons from PrEP implementation projects among young African women include: (1) awareness and demand creation with positive messaging about the benefits of PrEP are critical to motivate AGYW to consider this novel prevention technology and to foster awareness among peers, partners, parents and guardians to support AGYW's effective PrEP use; (2) PrEP initiation is high in projects that are integrating PrEP into youth-friendly clinics, family planning clinics and mobile clinics; (3) young African women at risk are initiating PrEP, based on behavioural characteristics, history of intimate partner violence, depression and 30% prevalence of chlamydia and/or gonorrhoea; (4) provision of youth-friendly PrEP delivery programmes that integrate reproductive health services, including contraception and the diagnosis and treatment of sexually transmitted infections, increase health impact; (5) messages that emphasize the necessity for high adherence while at potential risk of HIV exposure and support strategies that addresses AGYW's adherence challenges are essential; and, (6) a substantial proportion of AGYW do not persist with PrEP, and strategies are needed to help AGYW assess their ongoing need, motivation and challenges with persisting with PrEP.

CONCLUSIONS

PrEP is feasible to implement in integrated reproductive health service delivery models to reach African AGYW. While PrEP demonstration projects indicate that women with behavioural risks and high rates of sexually transmitted diseases are initiating PrEP; effective strategies to support AGYW's adherence and persistence with PrEP are needed. Lessons learned from oral PrEP delivery, a novel first generation HIV prevention product, are relevant to longer-acting and less adherence-dependent strategies which are currently in clinical trials.

Tenofovir 1% vaginal gel for prevention of HIV-1 infection in women in South Africa (FACTS-001): a phase 3, randomised, double-blind, placebo-controlled trial

BACKGROUND

Young women in southern Africa have substantial risk of HIV acquisition. Female-controlled biomedical interventions are needed to mitigate this risk. We aimed to assess the safety and efficacy of a pericoitally applied tenofovir 1% gel.

METHODS

We did a phase 3, double-blind, randomised, placebo-controlled trial at nine community-based clinical trial sites in South Africa to evaluate the safety and efficacy of tenofovir 1% gel. Sexually active women who were HIV negative and aged 18-30 years were enrolled. Participants were randomly assigned (1:1) using sequential participant numbers to either tenofovir 1% gel or a placebo gel (one dose within 12 h before sex and one dose within 12 h after sex [BAT-24 regimen]), using dynamic permuted block sizes of 8 and 16 within each site. Women received monthly HIV-1 testing, risk reduction support, physical examinations, and product dispensing for up to 27 months. The primary efficacy outcome was incident HIV infection and the primary safety outcome was occurrence of grade 2-4 adverse events, both analysed in the modified intention-to-treat population. To assess the efficacy of tenofovir gel, the cumulative probability of HIV infection was calculated for each treatment using the Kaplan-Meier method. This trial is registered with ClinicalTrials.gov, number NCT01386294.

FINDINGS

From Oct 11, 2011, to Aug 29, 2014, 3844 women were screened, 2059 enrolled, and 2029 included in the primary analysis (1032 in the tenofovir group and 1027 in the placebo group); 39 (4%) in the tenofovir group and 36 (4%) in the placebo group were lost to follow-up. 123 HIV-1 infections occurred over 3036 woman-years of observation; 61 in the tenofovir group (HIV incidence 4·0 per 100 woman-years, 95% CI 3·1-5·2) and 62 in the placebo group (4·0 per 100 woman-years, 3·1-5·2; incidence rate ratio [IRR] 0·98, 95% CI 0·7-1·4). A higher incidence of grade 2 adverse events was observed in the tenofovir group than in the placebo group (IRR 1·09, 95% CI 1·0-1·2; p=0·02). The most common grade 2 or higher product-related adverse events were hypophosphataemia (n=22 for tenofovir vs n=22 for placebo), genital symptoms (n=6 for tenofovir vs n=2 for placebo), or elevated transaminases (n=2 for tenofovir vs n=2 for placebo). No product-related serious adverse events were reported, and no differences in product-related adverse events (p=0·78), grade 3 events (p=0·64), or grade 4 events (p=0·74) were observed between treatment groups.

INTERPRETATION

Overall, pericoital tenofovir gel did not prevent HIV-1 acquisition in this population of young women at risk of HIV infection in South Africa. Alternate safe and effective products that are less user dependent than this product or do not require high adherence are needed.

FUNDING

The US Agency for International Development (USAID), the Bill & Melinda Gates Foundation, and the South African Department of Science and Technology and Department of Health.