Efficacy of oral pre-exposure prophylaxis (PrEP) for HIV among women with abnormal vaginal microbiota: a post-hoc analysis of the randomised, placebo-controlled Partners PrEP Study

Acceptability of a Combination Adherence Strategy to Support HIV Antiretroviral Therapy and Pre-exposure Prophylaxis Adherence During Pregnancy and Breastfeeding in Malawi

In two parallel pilot studies, we implemented a combination adherence intervention of patient-centered counselling and adherence supporter training, tailored to support HIV treatment (i.e., antiretroviral therapy) or prevention (i.e., pre-exposure prophylaxis, or PrEP) during pregnancy and breastfeeding. Using a mixed-methods approach, we evaluated the intervention's acceptability. We investigated engagement, satisfaction, and discussion content via survey to all 151 participants assigned to the intervention arm (51 women living with HIV, 100 PrEP-eligible women without HIV). We also conducted serial in-depth interviews with a subgroup (n = 40) at enrollment, three months, and six months. In the quantitative analysis, the vast majority reported high satisfaction with intervention components and expressed desire to receive it in the future, if made available. These findings were supported in the qualitative analysis, with favorable comments about counselor engagement, intervention content and types of support received from adherence supporters. Overall, these results demonstrate high acceptability and provide support for HIV status-neutral interventions for antiretroviral adherence.

Vaginal epithelial dysfunction is mediated by the microbiome, metabolome, and mTOR signaling

Bacterial vaginosis (BV) is characterized by depletion of Lactobacillus and overgrowth of anaerobic and facultative bacteria, leading to increased mucosal inflammation, epithelial disruption, and poor reproductive health outcomes. However, the molecular mediators contributing to vaginal epithelial dysfunction are poorly understood. Here we utilize proteomic, transcriptomic, and metabolomic analyses to characterize biological features underlying BV in 405 African women and explore functional mechanisms in vitro. We identify five major vaginal microbiome groups: L. crispatus (21%), L. iners (18%), Lactobacillus (9%), Gardnerella (30%), and polymicrobial (22%). Using multi-omics we show that BV-associated epithelial disruption and mucosal inflammation link to the mammalian target of rapamycin (mTOR) pathway and associate with Gardnerella, M. mulieris, and specific metabolites including imidazole propionate. Experiments in vitro confirm that type strain G. vaginalis and M. mulieris supernatants and imidazole propionate directly affect epithelial barrier function and activation of mTOR pathways. These results find that the microbiome-mTOR axis is a central feature of epithelial dysfunction in BV.

Role of the human vaginal microbiota in the regulation of inflammation and sexually transmitted infection acquisition: Contribution of the non-human primate model to a better understanding?

The human vaginal microbiota has a central role in the regulation of the female reproductive tract (FRT) inflammation. Indeed, on one hand an optimal environment leading to a protection against sexually transmitted infections (STI) is associated with a high proportion of Lactobacillus spp. (eubiosis). On the other hand, a more diverse microbiota with a high amount of non-Lactobacillus spp. (dysbiosis) is linked to a higher local inflammation and an increased STI susceptibility. The composition of the vaginal microbiota is influenced by numerous factors that may lead to a dysbiotic environment. In this review, we first discuss how the vaginal microbiota composition affects the local inflammation with a focus on the cytokine profiles, the immune cell recruitment/phenotype and a large part devoted on the interactions between the vaginal microbiota and the neutrophils. Secondly, we analyze the interplay between STI and the vaginal microbiota and describe several mechanisms of action of the vaginal microbiota. Finally, the input of the NHP model in research focusing on the FRT health including vaginal microbiota or STI acquisition/control and treatment is discussed.

Women for science and science for women: Gaps, challenges and opportunities towards optimizing pre-exposure prophylaxis for HIV-1 prevention

Preventing new HIV infections remains a global challenge. Young women continue to bear a disproportionate burden of infection. Oral pre-exposure prophylaxis (PrEP), offers a novel women-initiated prevention technology and PrEP trials completed to date underscore the importance of their inclusion early in trials evaluating new HIV PrEP technologies. Data from completed topical and systemic PrEP trials highlight the role of gender specific physiological and social factors that impact PrEP uptake, adherence and efficacy. Here we review the past and current developments of HIV-1 prevention options for women with special focus on PrEP considering the diverse factors that can impact PrEP efficacy. Furthermore, we highlight the importance of inclusion of female scientists, clinicians, and community advocates in scientific efforts to further improve HIV prevention strategies.

Pharmacogenomics of drug transporters for antiretroviral long-acting pre-exposure prophylaxis for HIV

The use of antiretrovirals (ARVs) as oral, topical, or long-acting pre-exposure prophylaxis (PrEP) has emerged as a promising strategy for HIV prevention. Clinical trials testing Truvada® [tenofovir disoproxil fumarate (TDF)/tenofovir (TFV) and emtricitabine (FTC)] as oral or topical PrEP in African women showed mixed results in preventing HIV infections. Since oral and topical PrEP effectiveness is dependent on adequate drug delivery and availability to sites of HIV infection such as the blood and female genital tract (FGT); host biological factors such as drug transporters have been implicated as key regulators of PrEP. Drug transporter expression levels and function have been identified as critical determinants of PrEP efficacy by regulating PrEP pharmacokinetics across various cells and tissues of the blood, renal tissues, FGT mucosal tissues and other immune cells targeted by HIV. In addition, biological factors such as genetic polymorphisms and genital inflammation also influence drug transporter expression levels and functionality. In this review, drug transporters and biological factors modulating drug transporter disposition are used to explain discrepancies observed in PrEP clinical trials. This review also provides insight at a pharmacological level of how these factors further increase the susceptibility of the FGT to HIV infections, subsequently contributing to ineffective PrEP interventions in African women.

Vaginal microbial shifts are unaffected by oral pre-exposure prophylaxis in South African women

Vaginal microbiota have been shown to be a modifier of protection offered by topical tenofovir in preventing HIV infection in women, an effect not observed with oral tenofovir-based pre-exposure prophylaxis (PrEP). It remains unclear whether PrEP can influence the vaginal microbiota composition. This study investigated the impact of daily oral tenofovir disoproxil fumarate in combination with emtricitabine for PrEP on the vaginal microbiota in South African women. At baseline, Lactobacillus iners or Gardnerella vaginalis dominant vaginal communities were observed in the majority of participants. In cross sectional analysis, vaginal microbiota were not affected by the initiation and use of PrEP. Longitudinal analysis revealed that Lactobacillus crispatus-dominant “cervicotypes 1 (CT1)” communities had high probability of remaining stable in PrEP group, but had a higher probability of transitioning to L. iners-dominant CT2 communities in non-PrEP group. L. iners-dominant communities were more likely to transition to communities associated with bacterial vaginosis (BV), irrespective of PrEP or antibiotic use. As expected, BV-linked CTs had a higher probability of transitioning to L. iners than L. crispatus dominant CTs and this shift was not associated with PrEP use.

Genital Inflammation Is Not Associated With Decreased Vaginal Tenofovir Concentrations in Women Taking Oral PrEP

BACKGROUND

We evaluated the association of inflammation and dysbosis on cervicovaginal fluid (CVF) tenofovir (TFV) concentrations in women taking oral tenofovir disoproxil fumarate/emtricitable for HIV pre-exposure prophylaxis (PrEP) in the United States.

SETTING

Thirty-five women in a HIV PrEP implementation study attended their week 24 visit at a San Diego research clinic and provided CVF specimens.

METHODS

Women in the Adherence Enhancement Guided by Individualized Texting and Drug Levels study had their CVF specimens evaluated for (1) sexually transmitted bacterial (Neisseria gonorrhoeae, Chlamydia trachomatis, Gardnerella, and Trichomonas vaginalis), viral (human papillomavirus, cytomegalovirus and herpes simplex virus-1/2) and fungal (Candida) infections; (2) microbiome composition by 16 S sequencing (V3-V4 region); and (3) cytokine profiles by enzyme-linked immunoassay (Interleukin-8, macrophage Inflammatory protein-1a, macrophage Inflammatory Protein-1b and interferon-γ-inducible protein-10). Univariate statistical analysis was used to determine factors associated with CVF TFV concentrations. CVF TFV of 100-1000 ng/mL benchmarked typical genital concentrations and TFV-diphosphate in dried blood spots of 700 fmol/punch was considered adequate adherence.

RESULTS

Thirty-five women had CVF specimens collected. No factor was associated with CVF TFV concentrations or discordance of blood and vaginal concentrations. Among 27 participants assessed for vaginosis (Candida, Gardnerella or Trichomonas), women with Gardnerella (n = 11) were more likely to have high (>1000 ng/mL) CVF TFV concentrations (82% versus 33%, P = 0.02).

CONCLUSIONS

Presence of genital viruses, cytokines, or vaginal community state types were not associated with low CVF TFV concentrations in cisgender women taking oral tenofovir disoproxil fumarate/emtricitable for PrEP. The surprising association observed between presence of Gardnerella and higher vaginal TFV concentrations needs further evaluation.

Expression, Activity, and Regulation of Phosphorylating Enzymes in Tissues and Cells Relevant to HIV-1 Sexual Transmission

Phosphorylating enzymes (PEs) are responsible for activating nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) such as tenofovir (TFV) and are critical for their conversion to obtain intracellular antiviral activity. However, there are limited data available regarding the expression of PEs and their activity in the female genital tract. This work compared the messenger RNA (mRNA) expression levels of PEs in human female genital tissue, immune cells, and animal models that are commonly used in human immunodeficiency virus (HIV) research. Furthermore, the effect of contraceptive hormones and proinflammatory cytokines on tenofovir diphosphate (TFV-DP) formation and efficacy in human vaginal, epithelial, and immune cells was also evaluated. We found that human vaginal and ectocervical tissues had similar mRNA expression for seven PEs tested. Polymerase chain reaction results revealed that creatine kinase brain (CKB), mitochondrial creatine kinase 1 (CKMT1), mitochondrial creatine kinase 2 (CKMT2), adenylate kinase AK3L1 (AK4), and nucleoside diphosphate kinase 1 (NME1) exhibited a 10- to 10,000-fold higher expression level in a vaginal epithelial cell line, VK2, compared with CD4⁺ T cells (p < .05). Medroxyprogesterone acetate (MPA)/progesterone (P4) and IL-1β/IL-8 treatment resulted in altered TFV-DP levels in VK2 and PM1 cells. MPA and P4 at concentrations above 0.1 μM, as well as IL-1β and IL-8 at concentrations above 10 ng/mL, significantly decreased HIV-1_BaL inhibition in PM1 cells when 1 μM TFV was added. However, this observed effect of hormones and cytokines was abrogated when TFV concentration was raised to 1 mM. These in vitro results elucidate the role of PEs in TFV metabolism and provide information regarding differences in PE tissue expression for animal models commonly used in HIV testing. This information can be applied to better understand and interpret data obtained using these models.

Microbial mismanagement: how inadequate treatments for vaginal dysbiosis drive the HIV epidemic in women

Women and girls represent a key population driving new HIV infections and persistence of the HIV pandemic. A key determinant of HIV susceptibility is the composition of the vaginal microbiome, which can influence the local immune cell population, inflammation status, and HIV prevention drug levels. While a low-diversity composition dominated by Lactobacillus crispatus is associated with a decreased risk of HIV acquisition, high diversity environments associated with bacterial vaginosis increase risk of HIV. Given the important role of the vaginal microbiome in determining HIV susceptibility, altering the microbiome towards a Lactobacillus-dominated state is an attractive complementary strategy to reduce HIV incidence rates. Here, we provide an overview of the mechanisms by which the vaginal microbiome may contribute to HIV acquisition risk. Furthermore, we address the advantages and limitations of historical treatments and emerging technologies under investigation to modify the vaginal microbiome, including: antibiotics, bacteriophages, probiotics, topicals, and engineered bacteria. By addressing the current state of vaginal microbiome knowledge and strategies for manipulation, we hope to amplify the growing calls for increased resources and research into vaginal microbial health, which will be essential to accelerating preventative efforts amongst the world's most vulnerable populations.

Depot Medroxyprogesterone Acetate and the Vaginal Microbiome as Modifiers of Tenofovir Diphosphate and Lamivudine Triphosphate Concentrations in the Female Genital Tract of Ugandan Women: Implications for Tenofovir Disoproxil Fumarate/Lamivudine in Preexposure Prophylaxis

BACKGROUND

Effective concentrations of antiretrovirals in the female genital tract (FGT) are critical for suppression of viral shedding or effective preexposure prophylaxis. The disposition of tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP) in the FGT have been previously described. Despite widespread use, however, lamivudine triphosphate (3TC-TP) exposure in the FGT is unknown. Depot medroxyprogesterone acetate (DMPA) and vaginal dysbiosis have been implicated in increased risk of human immunodeficiency virus (HIV) acquisition, but whether they alter TFV-DP or 3TC-TP exposure, and therefore compromise prevention efficacy, is unknown.

METHODS

Fifty premenopausal women living with HIV in Kampala, Uganda, and receiving daily tenofovir disoproxil fumarate/lamivudine were recruited. Ectocervical biopsies were obtained for quantification of TFV-DP and 3TC-TP using liquid chromatography-mass spectrometry. 16S ribosomal RNA gene sequencing was performed on DNA extracted from vaginal swabs. Wilcoxon rank-sum was used to test for differences between contraceptive groups.

RESULTS

3TC-TP concentrations were on average 17-fold greater than TFV-DP concentrations in cervical tissues. TFV-DP concentrations in cervical biopsies were 76% greater in DMPA users compared with women using nonhormonal contraception (n = 23 per group). Abundance of Lactobacillus in vaginal swabs was correlated with 3TC-TP concentrations in cervical tissues.

CONCLUSIONS

We found that TFV-DP concentrations were significantly greater in DMPA users compared with women using nonhormonal contraception, suggesting that prevention efficacy is unlikely to be compromised by DMPA use. Similar to reports of FTC-TP, 3TC-TP exposure was significantly greater than TFV-DP in cervical tissue and was correlated with abundance of Lactobacillus. These data support lamivudine as an option for preexposure prophylaxis.

CLINICAL TRIALS REGISTRATION

NCT03377608.

Hidden in plain sight: sex and gender in global pandemics

PURPOSE OF REVIEW

The global pandemic caused by the severe acute respiratory virus coronavirus 2 (SARS-CoV-2) has a male bias in mortality likely driven by both gender and sex-based differences between male and female individuals. This is consistent with sex and gender-based features of HIV infection and overlap between the two diseases will highlight potential mechanistic pathways of disease and guide research questions and policy interventions. In this review, the emerging findings from SARS-CoV-2 infection will be placed in the context of sex and gender research in the more mature HIV epidemic.

RECENT FINDINGS

This review will focus on the new field of literature on prevention, immunopathogenesis and treatment of SARS-CoV-2 referencing relevant articles in HIV for context from a broader time period, consistent with the evolving understanding of sex and gender in HIV infection. Sex-specific features of epidemiology and immunopathogenesis reported in COVID-19 disease will be discussed and potential sex and gender-specific factors of relevance to prevention and treatment will be emphasized.

SUMMARY

Multilayered impacts of sex and gender on HIV infection have illuminated pathways of disease and identified important goals for public health interventions. SARS-CoV-2 has strong evidence for a male bias in disease severity and exploring that difference will yield important insights.

Southern African guidelines on the safe, easy and effective use of pre-exposure prophylaxis: 2020

No abstract  available.

Impact of vaginal microbiome communities on HIV antiretroviral-based pre-exposure prophylaxis (PrEP) drug metabolism

Despite the efficacy of antiretroviral-based pre-exposure prophylactics (PrEP) in men who have sex with men, studies in women have produced widely varying outcomes. Recent evidence demonstrates that vaginal microbial communities are associated with increased HIV acquisition risk and may impact PrEP efficacy. Here, we investigate the mechanisms underlying how vaginal bacteria alter PrEP drug levels and impact HIV infection rates ex vivo. Using cervicovaginal lavages (CVLs) from women with or without bacterial vaginosis (BV), we identified microbial metabolism of PrEP drugs in BV samples through LC-MS/MS analysis of soluble drug levels and metabolite formation in dual T-cell cultures. CVL samples were assessed for microbiome analysis using sequencing of bacterial 16S rRNA genes. We also observed non-Lactobacillus bacteria that are associated with BV may potentially impact PrEP efficacy through increased HIV infection rates in co-cultures containing Lactobacillus or BV bacteria, PrEP drugs, CEM-GFP cells, and HIV-1_LAI virus. Finally, we used these data to develop a novel predictive mathematical simulation modeling system to predict these drug interactions for future trials. These studies demonstrate how dysbiotic vaginal microbiota may impact PrEP drugs and provides evidence linking vaginal bacteria to PrEP efficacy in women.

HIV prevention strategies with antiretroviral drugs as pre-exposure prophylactics (PrEP) are not efficacious in women, in part due to biological factors such as the vaginal microbiome. Lactobacillus spp. prevent the colonization of dysbiotic bacteria (i.e. bacterial vaginosis), which is associated with increased HIV transmission. However, the role these microbes play in altering the pharmacokinetics of PrEP drugs is currently unknown. Here we show that primary bacteria from women with dysbiosis impact PrEP drug levels and kinetics. We found that dysbiotic microbes metabolize PrEP drugs faster than target cell uptake, and significantly alter HIV infection rates in vitro, and this can be predicted with novel computational modeling. Our results demonstrate that the vaginal microbiome may play a key role in HIV prevention through altering therapeutic drug levels via metabolism. Thus, better measurements and interventions for vaginal dysbiosis will be critical in improving the efficacy of HIV prevention efforts in women.

Transmission routes of human immunodeficiency virus and affecting factors

Acquired immunodeficiency syndrome (AIDS) was first reported more than 30 years ago among homosexuals in the United States. The epidemiology of this disease indicates that there are three modes of transmission: Blood, mother-to-child, and sexual contact transmission. The pathogen of AIDS is human immunodeficiency virus (HIV), primarily HIV-1. HIV-1 could not break through the structurally and functionally integral skin, and primarily invades the human body through the mucosa irrespective of their integrity. Therefore, the mucosae are the natural transmission routes for HIV-1. The mucosae involved in HIV-1 transmission include the mucosae of the gastrointestinal tract and the urogenital tract. The risks of HIV-1 transmission vary significantly between mucosal sites and individuals, and are associated with mucosal integrity, abundance of target cells, immune status of the host, commensal microbes, and host genetic background. Many factors are closely related to the barrier function of the mucosa, and studies on their roles in HIV-1 invasion could promote the prevention and control of mucosal transmission of HIV-1.

Topical Microbicides in HIV Prevention: State of the Promise

HIV topical microbicides are products with anti-HIV activity, generally incorporating a direct-acting antiretroviral agent, that when applied to the vagina or rectum have the potential to prevent the sexual acquisition of HIV in women and men. Topical microbicides may meet the prevention needs of individuals and groups for whom oral daily forms of pre-exposure prophylaxis (PrEP) have not been acceptable. Microbicides can provide personal control over HIV prevention and offer the possibility of discreet use, qualities that may be particularly important for receptive partners in sexual relationships such as women and transgender women and men, who together account for the clear majority of new HIV infections worldwide. Although the promise of such a product emerged nearly three decades ago, proof of concept has been demonstrated only within the last decade. A robust pipeline of microbicidal gels, films, inserts, and rings has been evaluated in multiple studies among at-risk women and men, and refinement of products for ease of use, reversibility, and high safety is the priority for the field.

Immune recovery markers in a double blind clinical trial comparing dolutegravir and raltegravir based regimens as initial therapy (SPRING-2)

Background

Multiple T-cell marker recovery (MTMR: CD4+ T-cells >500 cel/mm³ plus CD4+% >29% plus CD4+/CD8+ ratio >1) has been proposed as the most complete level of immune reconstitution. In this study we quantified differences in the CD4+/CD8+ ratio, CD4+% recovery and MTMR after starting HIV-1 treatment with dolutegravir (DTG) vs. raltegravir (RAL) plus a NRTI backbone.

Methods

Exploratory post-hoc analysis of the SPRING-2 study, a randomized double-blind clinical trial comparing DTG and RAL as third agents in naive HIV-infected patients at 100 sites in Canada, USA, Australia, and Europe. Percentage differences and corresponding precision based on 95% confidence intervals (CI) and p-values were calculated for i) CD4+/CD8+ ratio normalization, ii) CD4+% normalization, and iii) the achievement of MTMR.

Results

A total of 822 participants were analyzed (411 in each group). No statistically significant differences in the proportion of patients who reached a CD4+/CD8+ ratio ≥0.5 & ≥1 at w48 & w96 were observed. At w96, the proportion of patients with a CD4+/CD8+ ratio ≥1 was similar (30.43% DTG vs. 29.57% RAL). No differences were observed in the mean increase in CD4+/CD8+ ratio from baseline at both w48 & w96. Similarly, no significant differences in the CD4+/CD8+>29% were observed at w96 (72.95% DTG vs 69.28% RAL). The proportion of patients attaining MTMR criteria was also similar in the DTG group and the RAL group at w48 (20.33% vs. 18.26%; difference 2.07 (95%CI (-3.67;7.81) P = 0.481 and w96 (28.70% vs. 27.13; difference 1.56 (95%CI -5.22;8.34) P = 0.652).

Conclusion

After comparing DTG and RAL, no differences on immune recovery markers were observed.

Pre-Exposure Prophylaxis for HIV Prevention in Women: Current Status and Future Directions

Pre-exposure prophylaxis (PrEP) is a promising intervention to prevent HIV acquisition, with benefits both to the individual and to population-level health. PrEP is an opportunity to complement ongoing public health efforts to eliminate HIV. For women, PrEP can also serve as a gateway to access sexual and reproductive health (SRH) services. Clinical efficacy of PrEP was initially reported in women using a 1% tenofovir vaginal gel in 2010, followed by an efficacy trial of oral PrEP using TDF/FTC in men who have sex with men (MSM). Since then, further trials have reported efficacy in oral PrEP containing tenofovir in women and heterosexual men, while the subsequent trials for women using tenofovir gel reported no efficacy, stemming from difficulties in achieving adequate adherence. In an effort to offer women additional choices to oral PrEP, alternative modalities are being tested in clinical research, including long-acting injectable formulations and intra-vaginal rings. In 2015, a meta-analysis of clinic trials and open-label extension studies led to the World Health Organization (WHO) strongly recommending the provision of oral PrEP containing tenofovir for any person at substantial risk of HIV infection, irrespective of gender or population group. Currently, PrEP services for women around the world, including those who are either pregnant or breastfeeding, remain limited. Outside sub-Saharan Africa, most PrEP programmes are focused on MSM. South Africa, Kenya, and the USA have the greatest utilization of oral PrEP by women. Yet, since 2012, of the estimated > 300,000 people globally who have initiated PrEP, a minority are women. In this narrative review, we examine the most recent literature on clinical and implementation PrEP research among women. We highlight the high burden of disease related to common sexually transmitted infections (STIs) in women, and the opportunity to integrate PrEP and other HIV prevention services, STI case management, and family planning services, as part of a more robust package of SRH services. Raising awareness on PrEP amongst women and their healthcare providers, minimizing gaps in access, and ensuring adherence and persistence of PrEP during periods of risk are critical issues if PrEP can have a meaningful impact on reducing HIV incidence in women globally.

The Effect of Antiretroviral Therapy Initiation on the Vaginal Microbiome in HIV-Infected Women

Background

The impact of antiretroviral therapy (ART) initiation on the vaginal microbiome is unknown. This is of particular importance among women living in sub-Saharan Africa. Understanding this relationship could help elucidate if and how the host immune system interacts with the vaginal microbiome.

Methods

The vaginal microbiome of HIV-1/HSV-2-coinfected women (n = 92) in Uganda was evaluated from self-collected vaginal swabs 1 month pre-ART and at 4 and 6 months post-ART initiation. The vaginal microbiome was characterized by 16S rRNA gene-based sequencing and quantitative polymerase chain reaction. Vaginal community state types (CSTs) were identified using proportional abundance data. Changes in microbiome composition were assessed with permutational analyses of variance (PerMANOVA).

Results

Five vaginal CSTs were identified, which varied significantly by bacterial load (P < .01): CST-1 was characterized by Lactobacillus iners, CST-2 by Gardnerella, CST-3 by Gardnerella and Prevotella, CST-4 by Lactobacillus crispatus, and CST-5 was highly diverse. Vaginal microbiome composition also did not change significantly after ART initiation (P = .985). Immune reconstitution after ART initiation did not affect vaginal microbiome CST assignment (P = .722) or individual-level changes in bacterial load (log response ratio [interquartile range], -0.50 [-2.75 to 0.38] vs -0.29 [-2.03 to 1.42]; P = .40).

Conclusions

The vaginal microbiome of HIV-infected women was not affected by the initiation of ART or immune reconstitution in this observational study. Further research is needed to explore the long-term effects of ART treatment on the vaginal microbiome.

Update on HIV Preexposure Prophylaxis: Effectiveness, Drug Resistance, and Risk Compensation

PURPOSE OF REVIEW

In 2019, the US government launched an initiative to decrease new HIV infections by 90% over the next decade. Studies have demonstrated the efficacy of HIV preexposure prophylaxis (PrEP) for high-risk populations, and the United States Preventative Services Task Force has issued a grade A recommendation for PrEP, indicating substantial net benefit. However, questions have been raised about the effectiveness of PrEP in clinical settings and whether PrEP use might promote antiretroviral drug resistance and increased sexual risk behaviors, which could increase transmission of bacterial sexually transmitted infections. In this narrative review, we summarize recent evidence of the effectiveness of PrEP when provided in clinical and community settings, the emergence of antiretroviral drug resistance during PrEP use, and associations between PrEP use and increased sexual risk behaviors. We also review novel PrEP modalities that are being developed to optimize PrEP acceptability, adherence, and effectiveness.

RECENT FINDINGS

Studies suggest that PrEP is effective when provided in clinical settings. However, PrEP uptake and impact have been limited in the USA thus far, and major disparities in access to PrEP exist. In addition, there is evidence that drug resistance can occur with PrEP use, particularly with inadvertent PrEP use during undiagnosed acute HIV infection. Risk compensation can also occur with PrEP use and has been associated with increased sexually transmitted infections. Promising new modalities for PrEP could expand options. PrEP has strong potential to decrease HIV incidence. However, disparities in access must be addressed to ensure equity and impact for PrEP. While drug resistance and risk compensation can occur with PrEP use, these are not valid reasons to withhold PrEP from patients given its substantial protective benefits.

The Influence of Cervicovaginal Microbiota on Mucosal Immunity and Prophylaxis in the Battle against HIV

PURPOSE OF REVIEW

Young women in sub-Saharan Africa bear a disproportionate burden of the global HIV epidemic. In this review, we examine how cervicovaginal microbiota modulate structural and immune defenses in the female genital tract and influence HIV susceptibility.

RECENT FINDINGS

Highly diverse, anaerobic cervicovaginal microbiota prevalent in sub-Saharan African women increase HIV acquisition risk by over fourfold. These bacteria weaken the barrier properties of the vaginal mucosa and increase local inflammation and HIV target cell recruitment, creating an environment permissive to HIV. These communities also diminish the prophylactic efficacy of topical tenofovir and therefore may modulate both biological susceptibility to HIV and the effectiveness of pre-exposure prophylaxis (PrEP). Cervicovaginal bacteria influence multiple reproductive health outcomes, including HIV acquisition. High-diversity, low Lactobacillus abundance cervicovaginal communities prevalent in many regions with high HIV incidence are associated with increased HIV susceptibility. A better understanding of the host-microbial interactions mediating this risk is important to reduce HIV infections, particularly among women living in sub-Saharan Africa.

The genital tract and rectal microbiomes: their role in HIV susceptibility and prevention in women

INTRODUCTION

Young women in sub-Saharan Africa are disproportionately affected by HIV, accounting for 25% of all new infections in 2017. Several behavioural and biological factors are known to impact a young woman's vulnerability for acquiring HIV. One key, but lesser understood, biological factor impacting vulnerability is the vaginal microbiome. This review describes the vaginal microbiome and examines its alterations, its influence on HIV acquisition as well as the efficacy of HIV prevention technologies, the role of the rectal microbiome in HIV acquisition, advances in technologies to study the microbiome and some future research directions.

DISCUSSION

Although the composition of each woman's vaginal microbiome is unique, a microbiome dominated by Lactobacillus species is generally associated with a "healthy" vagina. Disturbances in the vaginal microbiota, characterized by a shift from a low-diversity, Lactobacillus-dominant state to a high-diversity non-Lactobacillus-dominant state, have been shown to be associated with a range of adverse reproductive health outcomes, including increasing the risk of genital inflammation and HIV acquisition. Gardnerella vaginalis and Prevotella bivia have been shown to contribute to both HIV risk and genital inflammation. In addition to impacting HIV risk, the composition of the vaginal microbiome affects the vaginal concentrations of some antiretroviral drugs, particularly those administered intravaginally, and thereby their efficacy as pre-exposure prophylaxis (PrEP) for HIV prevention. Although the role of rectal microbiota in HIV acquisition in women is less well understood, the composition of this compartment's microbiome, particularly the presence of species of bacteria from the Prevotellaceae family likely contribute to HIV acquisition. Advances in technologies have facilitated the study of the genital microbiome's structure and function. While next-generation sequencing advanced knowledge of the diversity and complexity of the vaginal microbiome, the emerging field of metaproteomics, which provides important information on vaginal bacterial community structure, diversity and function, is further shedding light on functionality of the vaginal microbiome and its relationship with bacterial vaginosis (BV), as well as antiretroviral PrEP efficacy.

CONCLUSIONS

A better understanding of the composition, structure and function of the microbiome is needed to identify opportunities to alter the vaginal microbiome and prevent BV and reduce the risk of HIV acquisition.

Anal Microbial Patterns and Oncogenic Human Papillomavirus in a Pilot Study of Nigerian Men Who Have Sex with Men at Risk for or Living with HIV

To cluster anal microbiota and define microbial patterns associated with biological, clinical, and behavioral correlates among Nigerian men who have sex with men (MSM) living with or at risk for HIV. In this cross-sectional pilot study, the 15 most abundant 16S taxa in the anal microbiota of 113 MSM underwent unsupervised K-means clustering and z-score comparisons to define similarities and dissimilarities among 4 microbiota taxonomic profiles. Distributions of oncogenic HPV (high-risk human papillomavirus [HR-HPV]), concurrent HIV, antiretroviral therapy (ART), and other clinical and behavioral data were evaluated using Fisher's exact and Kruskal-Wallis tests to determine biological signatures of cluster membership. Prevotella was consistently represented in each cluster, but the average composition ranged from 14% to 44%. Cluster 2 was enriched with a member of the Fusobacteria phylum, Sneathia (29%). More participants of cluster 2 were HIV infected and taking ART (83%, 5/6), were virally suppressed (80%, 4/5), had HPV-16 (66.7%, 4/6), and reported no vaginal sex partners (83%, 5/6). HPV-35, a highly prevalent oncogenic HPV in Nigeria, was observed in all clusters except cluster 2 (0%, 0/6). Other covariates were similar across clusters (all p > .05). K-means unsupervised clustering, a canonical pattern recognition method, generalized the microbial community composition and structure while accounting for among sample variability. Further studies are needed to evaluate whether an anal microbial community enriched with members of the Fusobacteria phylum is associated with HIV-infected MSM who are virally suppressed and have a concurrent HPV-16.

A systematic review of adherence to oral pre-exposure prophylaxis for HIV - how can we improve uptake and adherence?

Introduction

Oral pre-exposure prophylaxis (PrEP) is an effective strategy to reduce the risk of HIV transmission in high risk individuals. However, the effectiveness of oral pre-exposure prophylaxis is highly dependent on user adherence, which some previous trials have struggled to optimise particularly in low and middle income settings. This systematic review aims to ascertain the reasons for non-adherence to pre-exposure prophylaxis to guide future implementation.

Methods

We performed structured literature searches of online databases and conference archives between August 8, 2016 and September 16, 2017. In total, 18 prospective randomized control trials and implementation studies investigating oral pre-exposure prophylaxis were reviewed. A structured form was used for data extraction and findings summarized regarding efficacy, effectiveness, adherence and possible reasons for non-adherence.

Results

Adherence varied between differing populations both geographically and socioeconomically. Common reasons for non-adherence reported over multiple studies were; social factors such as stigma, low risk perception, low decision making power, an unacceptable dosing regimen, side effects, and the logistics of daily life. Oral pre-exposure prophylaxis with included antiviral regimens was not associated with a high risk of antiviral resistance development in the reviewed studies.

Conclusion

Our findings indicate that oral pre-exposure prophylaxis should be delivered within a holistic intervention, acknowledging the other needs of the targeted demographic in order to maximise acceptability. Socioeconomic factors and poor governmental policy remain major barriers to widespread implementation of pre-exposure prophylaxis.

HIV Antiretroviral Pre-Exposure Prophylaxis: Development Challenges and Pipeline Promise

The US Food and Drug Administration (FDA) approved oral daily tenofovir/emtricitabine (Truvada) for pre-exposure prophylaxis of human immunodeficiency virus (HIV) infection in 2012 on the basis of two randomized controlled trials (RCTs), one in men who have sex with men (MSM) and another in HIV serodiscordant heterosexual couples. Subsequently, even greater efficacy has been demonstrated in MSM with rapid population-level incidence reductions in some locations. In contrast, studies of antiretroviral pre-exposure prophylaxis (PrEP) in heterosexual women showed only modest or no efficacy, largely attributed to low adherence. The mixed results of antiretroviral-based PrEP bear witness to unique drug development challenges at this complicated intersection of sexual behavior, public health, and drug development. Multiple innovative methods and formulation strategies followed to address unmet medical needs of persons struggling with daily oral PrEP adherence or preference for nonsystemic PrEP options. Clinical pharmacology plays essential roles throughout this PrEP development process, especially in early product development and through pharmacologically informed enhancement and interpretation of clinical trials.

Pharmacology of Antiretrovirals in the Female Genital Tract for HIV Prevention

Preexposure prophylaxis (PrEP) is a powerful tool that, as part of a comprehensive prevention package, has potential to significantly impact the HIV epidemic. PrEP effectiveness is believed to be dependent on the exposure and efficacy of antiretrovirals at the site of HIV transmission. Clinical trial results as well as modeling and simulation indicate the threshold of adherence required for PrEP efficacy of emtricitabine/tenofovir disoproxil fumarate may differ between sites of HIV transmission with less forgiveness for missed doses in women exposed through genital tissue compared to people exposed through colorectal tissue. This suggests a role for local and host factors to influence mucosal pharmacology. Here we review the mucosal pharmacology of antiretrovirals in the female genital tract and explore potential determinants of PrEP efficacy. Host factors such as inflammation, coinfections, hormonal status, and the vaginal microbiome will be explored as well as the role of drug-metabolizing enzymes and transporters in regulating local drug exposure. The use of preclinical and early clinical models to predict clinical effectiveness is also discussed.

Repeated rectal application of a hyperosmolar lubricant is associated with microbiota shifts but does not affect PrEP drug concentrations: results from a randomized trial in men who have sex with men

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is highly effective in preventing HIV infection among men who have sex with men (MSM). The effects of consistent personal lubricant use in the rectum on tissue PrEP drug concentrations and the rectal microbiota are unknown. We investigated rectal PrEP drug concentrations and the microbiota in MSM before and after repeated rectal application of a hyperosmolar lubricant.

METHODS

We randomized 60 HIV-negative MSM to apply 4 mL of hyperosmolar rectal lubricant daily (n = 20), take daily oral TDF/FTC (n = 19), or both (n = 21) for seven days. Blood, rectal biopsies and rectal secretions were collected via rigid sigmoidoscopy before and on day 8 after product use. Tenofovir (TFV) and FTC as well as their intracellular metabolites tenofovir-diphosphate (TFV-DP), FTC-triphosphate (FTC-TP) were measured by HPLC-mass spectrometry. Rectal mucosal microbiota was sequenced with 16S rRNA sequencing using Illumina MiSeq.

RESULTS

Seven days of lubricant application was not associated with differences in PrEP drug concentrations in rectal tissue or secretions. Lubricant use was associated with a decrease in the relative abundance of the Bacteroides genus (p = 0.01) and a non-significant increase in the Prevotella genus (p = 0.09) in the rectum. PrEP drug concentrations in rectal tissue and secretions were not associated with microbiota composition or diversity either before or after lubricant use.

CONCLUSIONS

Repeated rectal application of a hyperosmolar lubricant does not affect mucosal PrEP drug concentrations but is associated with changes in the rectal microbiome.

The human microbiome: implications for health and disease, including HIV infection

Our increased understanding of the human microbiome has brought insight into the role it plays in health and disease, including HIV infection. Studies have shown that the gut microbiome is less diverse in individuals with HIV infection than in noninfected control subjects. Efforts to modify the microbiome to bolster immune reconstitution in people with HIV infection have so far been unsuccessful. The vaginal microbiome affects risk of HIV acquisition, with Lactobacillus dominance being protective compared with vaginosis characterized by larger populations of Gardnerella. The vaginal microbiome might also affect efficacy of topical tenofovir disoproxil fumarate preexposure prophylaxis. This article summarizes a presentation by Robert T. Schooley, MD, at the IAS-USA continuing education program held in San Francisco in May 2018.

HIV

The benefits of combination antiretroviral therapy (cART) for HIV replication and transmission control have led to its universal recommendation. Many people living with HIV are, however, still undiagnosed or diagnosed late, especially in sub-Saharan Africa, where the HIV disease burden is highest. Further expansion in HIV treatment options, incorporating women-centred approaches, is essential to make individualised care a reality. With a longer life expectancy than before, people living with HIV are at an increased risk of developing non-AIDS comorbidities, such as cardiovascular diseases and cancers. Antiretroviral strategies are evolving towards a decrease in drug burden, and some two-drug combinations have proven efficacy for maintenance therapy. Investigational immune checkpoint inhibitors and broadly neutralising antibodies with effector functions have energised the HIV cure research field as the search for an effective vaccine continues. In this Seminar, we review advances and challenges relating to the goal of an AIDS-free world.

Vaginal microbiota and susceptibility to HIV

: Bacterial vaginosis, characterized by the replacement of the Lactobacillus-dominant microbiota with anaerobic bacteria and facultative Gram-negative rods, has been associated with adverse reproductive health outcomes including HIV acquisition. With the advent of newer molecular techniques, the vaginal microbiota can be investigated in more detail and the association with HIV examined more thoroughly. This review examines recent evidence suggesting that vaginal dysbiosis with increased microbial diversity, specific vaginal bacterial communities, and the presence and concentrations of some individual bacterial species, may increase HIV susceptibility. Potential mechanisms through which vaginal microbiota could impact HIV susceptibility are discussed. On the basis of the available data, this review finds that there is a modest, but growing, body of evidence linking vaginal microbiota to HIV susceptibility in women. The evidence could be strengthened through two main pathways. First, laboratory studies such as ex-vivo or animal experiments are needed to move from plausible mechanisms towards proven mechanisms that explain an effect of the vaginal microbiota on HIV susceptibility. Second, experimental evidence could directly test the hypothesis that sustaining optimal microbiota reduces HIV risk, though there are important obstacles to conducting such studies. Finally, this review examines strong evidence from a recent publication suggesting that deviations from an optimal vaginal microbiome, and particularly the presence of some bacterial communities with high relative abundance of Gardnerella vaginalis, reduces the efficacy of vaginal tenofovir-based microbicides.

The Vaginal Microbiome and its Potential to Impact Efficacy of HIV Pre-exposure Prophylaxis for Women

PURPOSE OF REVIEW

This review describes existing evidence addressing the potential modulation of pre-exposure prophylaxis (PrEP) products, specifically 1% tenofovir (TFV) gel and oral tenofovir-based PrEP, by vaginal dysbiosis and discusses future considerations for delivering novel, long-acting PrEP products to women at high risk for vaginal dysbiosis and HIV.

RECENT FINDINGS

We describe results from analyses investigating the modification of PrEP efficacy by vaginal dysbiosis and studies of biological mechanisms that could render PrEP ineffective in the presence of specific microbiota. A secondary analysis from the CAPRISA-004 cohort demonstrated that there is no effect of the 1% TFV gel in the presence of non-Lactobacillus dominant microbiota. Another recent analysis comparing oral tenofovir-based PrEP efficacy among women with and without bacterial vaginosis in the Partners PrEP Study found that oral PrEP efficacy is not modified by bacterial vaginosis. Gardnerella vaginalis, commonly present in women with vaginal dysbiosis, can rapidly metabolize TFV particularly when it is locally applied and thereby prevent TFV integration into cells. Given that vaginal dysbiosis appears to modulate efficacy for 1% TFV gel but not for oral tenofovir-based PrEP, vaginal dysbiosis is potentially less consequential to HIV protection from TFV in the context of systemic drug delivery and high product adherence. Vaginal dysbiosis may undermine the efficacy of 1% TFV gel to protect women from HIV but not the efficacy of oral PrEP. Ongoing development of novel ring, injectable, and film-based PrEP products should investigate whether vaginal dysbiosis can reduce efficacy of these products, even in the presence of high adherence.

Genital inflammation undermines the effectiveness of tenofovir gel in preventing HIV acquisition in women

Several clinical trials have demonstrated that antiretroviral (ARV) drugs, taken as pre-exposure prophylaxis (PrEP), can prevent HIV infection¹, with the magnitude of protection ranging from -49 to 86%^2–11. While these divergent outcomes are thought to be due primarily to product adherence¹², biological factors likely contribute¹³. Despite selective recruitment of higher risk participants for prevention trials, HIV risk is heterogeneous, even within higher risk groups^14–16. To determine whether this heterogeneity could influence PrEP outcomes, we undertook a post-hoc prospective analysis of the CAPRISA 004 tenofovir 1% gel trial (n=774), one of the first trials to demonstrate protection against HIV infection. Concentrations of nine pro-inflammatory cytokines were measured in cervicovaginal lavages at >2,000 visits, and a graduated cytokine score was used to define genital inflammation. In women without genital inflammation, tenofovir was 57% protective against HIV (95% CI: 7 to 80%), compared to 3% (95% CI: −104 to 54%) if genital inflammation was present. Among high gel adherers, tenofovir protection was 75% (95% CI: 25 to 92%) in women without inflammation compared to −10% (95% CI: −184 to 57%) in women with inflammation. Host immune predictors of HIV risk may modify the effectiveness of HIV prevention tools; reducing genital inflammation in women may augment HIV prevention efforts.

Impact of antiretroviral drugs on the microbiome: unknown answers to important questions

PURPOSE OF REVIEW

Little is known on how different antiretroviral (ARV) drugs affect the gut microbiome in HIV infection; and conflicting data exists on the effect of ARV drugs on residual inflammation/immune activation and microbial translocation.

RECENT FINDINGS

Gut microbiome involvement in the transmission and pathogenesis of HIV infection is increasingly being recognized. Various studies have shown that antiretroviral therapy (ART) is unable to restore gut health despite effective suppression of plasma HIV viremia. Indeed, the resolution of residual inflammation and gut microbial translocation is partial under ART. Very recent studies have provided new evidence that ARV combinations can differentially affect the gut microbiome, immune activation and microbial translocation. Furthermore, a recent article uncovered a link between drug metabolism and specific microbial species indicating that microbes can directly metabolically degrade ARV drugs when administered topically.

SUMMARY

There are still many unanswered questions regarding ARVs and the gut microbiome. It is, therefore, critical for researchers to address the effect of distinct ARV drugs on the microbiome and vice versa: the effects of the microbiome on ARV drug metabolism, and speculate about possible therapeutic avenues.

Impact of dolutegravir and efavirenz on immune recovery markers: results from a randomized clinical trial

OBJECTIVES

CD4/CD8 ratio and CD4⁺ T-cell percentage (CD4%) predicts the risk of AIDS and non-AIDS events. Multiple T-cell marker recovery (MTMR) has been proposed as the most complete level of immune reconstitution. We quantified differences in the CD4/CD8 ratio, CD4% recovery and MTMR after starting HIV-1 treatment with dolutegravir/abacavir/lamivudine vs. efavirenz (EFV)/tenofovir (TDF)/emtricitabine (FTC).

METHODS

Exploratory post hoc analysis of the SINGLE study, a randomized double-blind, clinical trial. Percentage differences and corresponding precision based on 95% confidence intervals, and p values were calculated for CD4/CD8 ratio normalization, CD4% normalization and the achievement of MTMR. Cox models taking into account competing risks were used to estimate sub-hazard ratios when comparing the times to normalization of the CD4/CD8 ratio and the CD4% by treatment arm.

RESULTS

Data from 833 participants were analysed (414 in the dolutegravir/abacavir/lamivudine arm). There were no statistically significant differences in the proportion of patients who reached a CD4/CD8 ratio ≥0.5 at weeks 48 and 96. However, at week 96, the proportion of patients with a CD4/CD8 ratio ≥1 was higher in the EFV-TDF-FTC group (difference, 11.70; 95% confidence interval, 4.49-18.91; p 0.002). The decrease from baseline in CD8⁺ cell count was consistently greater in the EFV-TDF-FTC arm. Analysis of CD4⁺ percentages showed no significant differences during the study. The proportion of patients attaining a MTMR was higher in the EFV-TDF-FTC group, although the difference was only statistically significant at week 96 (p 0.001).

CONCLUSIONS

EFV-TDF-FTC showed significantly greater increases in CD4/CD8 ratio ≥1.0 or MTMR beyond treatment week 96. Additional studies are necessary to better understand the impact of these findings.

Bugs, drugs, and HIV: the role of the vaginal microbiome in HIV risk and antiretroviral efficacy for HIV prevention

Advances in molecular tools to characterize the microbiome have led to the discovery of unique roles for microbes in human disease. Findings that the female genital microbiome can influence HIV acquisition and prevention emphasize the importance of microbiome analysis in clinical trials that assess the efficacy of HIV prevention interventions.