Barriers to a cure for HIV in women

Sex Differences in HIV Infection

Biological sex has wide-ranging impacts on HIV infection spanning differences in acquisition risk, the pathogenesis of untreated infection, impact of chronic treated disease and prospects for HIV eradication or functional cure. This chapter summarizes the scope of these differences and discusses several features of the immune response thought to contribute to the clinical outcomes.

Lessons for Understanding Central Nervous System HIV Reservoirs from the Last Gift Program

PURPOSE OF REVIEW

Deep tissue HIV reservoirs, especially within the central nervous system (CNS), are understudied due to the challenges of sampling brain, spinal cord, and other tissues. Understanding the cellular characteristics and viral dynamics in CNS reservoirs is critical so that HIV cure trials can address them and monitor the direct and indirect effects of interventions. The Last Gift program was developed to address these needs by enrolling altruistic people with HIV (PWH) at the end of life who agree to rapid research autopsy.

RECENT FINDINGS

Recent findings from the Last Gift emphasize significant heterogeneity across CNS reservoirs, CNS compartmentalization including differential sensitivity to broadly neutralizing antibodies, and bidirectional migration of HIV across the blood-brain barrier. Our findings add support for the potential of CNS reservoirs to be a source of rebounding viruses and reseeding of systemic sites if they are not targeted by cure strategies. This review highlights important scientific, practical, and ethical lessons learned from the Last Gift program in the context of recent advances in understanding the CNS reservoirs and key knowledge gaps in current research.

Sex Differences in Human Immunodeficiency Virus Persistence and Reservoir Size During Aging

BACKGROUND

Sex differences in human immunodeficiency virus (HIV) reservoir dynamics remain underexplored.

METHODS

Longitudinal samples from virally suppressed midlife women (n = 59, median age 45 years) and age-matched men (n = 31) were analyzed retrospectively. At each time point, we measured sex hormones (by means of enzyme-linked immunosorbent assay) and cellular HIV DNA and RNA (by means of digital droplet polymerase chain reaction). Number of inducible HIV RNA+ cells, which provides an upper estimate of the replication-competent reservoir, was quantified longitudinally in a different subset of 14 women, across well-defined reproductive stages. Mixed-effects models included normalized reservoir outcomes and sex, time since antiretroviral therapy (ART) initiation, and the sex-by-time interaction as predictors.

RESULTS

At ART initiation, women and men had median (interquartile range [IQR]) CD4+ T-cell counts of 204/μL (83-306/μL) versus 238/μL (120-284/μL), respectively; median ages of 45 (42-48) versus 47 (43-51) years; and median follow-up times of 79.2/μL (60.5-121.1/μL) versus 66.2/μL (43.2-80.6/μL) months. We observed a significant decline of total HIV DNA over time in both men and women (P < .01). However, the rates of change differed significantly between the sexes (P < .01), with women having a significantly slower rate of decline than men, more pronounced with age. By contrast, the levels of inducible HIV RNA increased incrementally over time in women during reproductive aging (P < .01).

CONCLUSIONS

In contrast to men, in whom the HIV reservoir steadily declines with aging, the HIV reservoir in women is more dynamic. Total HIV DNA (including intact and defective genomes) declines more slowly in women than in men, while the inducible HIV RNA+ reservoir, which is highly enriched in replication-competent virus, increases in women after menopause.

Cardiovascular Implications of Immune Disorders in Women

Immune responses differ between men and women, with women at higher risk of developing chronic autoimmune diseases and having more robust immune responses to many viruses, including HIV and hepatitis C virus. Although immune dysregulation plays a prominent role in chronic systemic inflammation, a key driver in the development of atherosclerotic cardiovascular disease (ASCVD), standard ASCVD risk prediction scores underestimate risk in populations with immune disorders, particularly women. This review focuses on the ASCVD implications of immune dysregulation due to disorders with varying global prevalence by sex: autoimmune disorders (female predominant), HIV (male-female equivalent), and hepatitis C virus (male predominant). Factors contributing to ASCVD in women with immune disorders, including traditional risk factors, dysregulated innate and adaptive immunity, sex hormones, and treatment modalities, are discussed. Finally, the need to develop new ASCVD risk stratification tools that incorporate variables specific to populations with chronic immune disorders, particularly in women, is emphasized.

Facilitators and barriers of women's participation in HIV clinical research in Switzerland: A qualitative study

OBJECTIVES

Women are underrepresented in most HIV clinical trials in Western countries, but their participation remains crucial as the lack of information on sex- and gender-specific effects may hinder the safety and efficacy of antiretroviral treatments. The aim of this study was to identify barriers to and facilitators of women's participation in HIV clinical trials in Switzerland.

METHODS

We conducted semi-structured interviews among 20 women with HIV to explore factors associated with non-participation in clinical trials. The interviewer presented to participants a clinical trial's description and discussed it with them. Lexicometric analysis on transcribed interviews identified three themes and eight sub-themes related to the pros and cons of participation in HIV clinical trials.

RESULTS

Participants evoked mainly decision-making drivers, concerns for women living with HIV and treatment side-effects. They highlighted the need for extensive information provided by trusted healthcare professionals on the research process as central to the decision to enrol in HIV clinical trials. Familial responsibilities were clearly identified as barriers to their participation, but not pregnancy. Additional preoccupations were other health concerns and comorbidities and the consequences of stopping ongoing antiretroviral treatments.

CONCLUSIONS

To overcome the barriers to the participation of women living with HIV in clinical research in Western countries, healthcare professionals and researchers should increase women's research literacy by involving them in the study design and by tailoring clinical trials to their social roles and health concerns. Trust in professionals is a facilitator of enrolment of women living with HIV that should be maintained.

HIV Reservoirs: Modeling, Quantification, and Approaches to a Cure

Biomedical research in animal models depends heavily on nonhuman primates (NHP) (Phillips et al., Am J Primatol 76(9):801-827, 2014). In their physiology, neurobiology, and, most importantly, their susceptibility to infectious diseases and subsequent immune responses, NHPs have many parallels with humans (Rhesus Macaque Genome Sequencing and Analysis Consortium et al., Science 316(5822):222-234, 2007). Different species of NHPs have served as important animal models for numerous infectious diseases spanning a wide range of pathogens (Gardner and Luciw, ILAR J 49(2):220-255, 2008). As a result of recognizing their utility in HIV research, NHPs have contributed to groundbreaking studies of disease pathogenesis, vaccination, and curative research (London et al., Lancet 2(8355):869-873, 1983; Henrickson et al., Lancet 1 (8321):388-390, 1983). Many African NHPs are considered natural hosts for SIV in which SIV infection is usually nonprogressive and does not cause acquired immunodeficiency syndrome (AIDS) (Chahroudi et al., Science 335(6073):1188-1193, 2012; Taaffe et al., J Virol 84(11):5476-5484, 2010). However, cross-species transmission of SIV strains to other NHPs or to humans (nonnatural hosts) leads to progressive disease and AIDS (Paiardini et al., Annu Rev Med 60:485-495, 2009). In particular, SIV infection of Asian rhesus macaques recapitulates many features of HIV infection in humans and therefore has become a widely used approach for contemporary HIV research into virus persistence and cure strategies (Gardner and Luciw, FASEB J 3(14):2593-2606, 1989). There are multiple factors that should be considered in HIV/SIV studies using NHPs including the particular monkey species and geographic background, age and sex, certain genetic properties, virus strain, route and dose of infection, interventional treatments, and prespecified study outcomes. Here, we discuss consideration of these factors to address specific questions in HIV cure research.

Considerations for Increasing Racial, Ethnic, Gender, and Sexual Diversity in HIV Cure-Related Research with Analytical Treatment Interruptions: A Qualitative Inquiry

Despite disproportionate incidence and prevalence of HIV among transgender individuals, cisgender women, and racial and ethnic minority groups, all remain underrepresented in HIV cure research. As HIV cure trials are scaled up, there is emerging research on ways to mitigate risks of HIV acquisition for sexual partners of analytical treatment interruption (ATI) trial participants. As such, it is imperative that HIV cure researchers consider the implications of implementing ATIs in populations that are disproportionately affected by HIV, but largely underrepresented in trials to date. In this qualitative study, we sought to derive triangulated perspectives on the social and ethical implications regarding ATIs and partner protection strategies during ATIs among under-represented populations. We conducted 21 in-depth interviews with 5 types of informants: bioethicists, community members [people living with HIV (PLWH) and their advocates], biomedical HIV cure researchers, sociobehavioral scientists, and HIV care providers. We analyzed the data using conventional content analysis and reduced the data to important considerations for implementing ATI trials in diverse communities and settings. Our study revealed the following key themes: (1) attention must be paid to gender and power dynamics in ATI trials; (2) ATI trials should be designed and implemented through the lenses of intersectionality and equity frameworks; (3) ATI trials may have both positive and negative effects on stigma for PLWH and their partners; and (4) partnership dynamics should be considered when designing ATI protocols. Our study generated actionable considerations that could be implemented in ATI trials to promote their acceptability to communities that have been underrepresented in HIV cure research to date. Research teams must invest in robust community and stakeholder engagement to define best practices. Paying attention to representation and equity will also promote better and more equitable implementation of HIV cure strategies once these become ready for rollout.

Tissue-specific differences in HIV DNA levels and mechanisms that govern HIV transcription in blood, gut, genital tract and liver in ART-treated women

INTRODUCTION

Sex-specific differences affect multiple aspects of HIV infection, yet few studies have quantified HIV levels in tissues from women. Since an HIV functional cure will likely require a major reduction of infected cells from most tissues, we measured total and intact HIV DNA and the HIV transcription profile in blood, gut, genital tract and liver from HIV-positive antiretroviral therapy (ART) -treated women.

METHODS

Peripheral blood mononuclear cells (PBMC) and biopsies from the gastrointestinal (ileum, colon, rectosigmoid +/- liver) and genital (ectocervix, endocervix and endometrium) tracts were collected from 6 ART-treated (HIV RNA < 200 copies/mL) women. HIV DNA (total and intact) and levels of read-through, initiated (total), 5'elongated, polyadenylated and multiply spliced HIV transcripts were measured by droplet digital PCR. Immunophenotyping of cells was performed using Cytometry by time of flight (CyTOF).

RESULTS

We detected total HIV DNA in all tissues and intact HIV DNA in blood, ileum, colon, rectosigmoid and ectocervix. Initiated HIV transcripts per provirus were higher in PBMC and endometrium than in ileum, colon, rectosigmoid, ectocervix or endocervix, and higher in the rectum than either ileum or colon. 5'Elongated HIV transcripts per provirus were comparable in PBMC and endometrium, but higher than in gut or cervical samples. Polyadenylated and multiply spliced HIV transcripts were detected in PBMC (6/6 and 3/6 individuals respectively), but rarely in the tissues.

CONCLUSIONS

These results suggest tissue-specific differences in the mechanisms that govern HIV expression, with lower HIV transcription in most tissues than blood. Therapies aimed at disrupting latency, such as latency-reversing or latency-silencing agents, will be required to penetrate into multiple tissues and target different blocks to HIV transcription.

Impact of dedicated women's outreach workers (WOWs) on recruitment of women in ACTG clinical studies

BACKGROUND

Despite efforts by the AIDS Clinical Trials Group (ACTG) to enroll representative numbers of diverse women, participation in ACTG studies in the United States remains largely white and male. To address this gap in women's participation in ACTG research, a one-year pilot study of dedicated women's outreach workers (WOWs) was proposed.

OBJECTIVES

included demonstrating that targeted recruitment efforts can expand community awareness of ACTG research and ensuring successful enrollment of women at the respective clinical research sites.

METHODS

The pilot study was conducted at two U.S. sites (Rutgers New Jersey Medical School and Emory Ponce de Leon Center in Atlanta, Georgia). The WOWs worked with site personnel to identify and reach out to women living with HIV and/or Hepatitis B or C at their respective sites and encourage them to join a clinical trial registry for those interested in participating in future clinical trials.

RESULTS

The Rutgers WOW approached 127 potential participants (of whom 100 joined the WOW registry) and screened 35 participants for open ACTG studies. The Emory WOW approached 120 participants, enrolling 86 into the WOW registry, and screened 51 potential participants for open ACTG studies during the WOW's tenure. The majority of women screened at both sites were women of color.

CONCLUSIONS

The WOW study team identified several lessons learned that can inform future efforts to engage women living with HIV in clinical research. First, success in engaging women is proportional to level of funding and institutional support. Second, there is a need for a more gender-inclusive scientific agenda as women are more likely to participate if studies address topics of interest to them. Third, meaningful engagement is a two-way street.

Screening and Enrollment by Sex in Human Immunodeficiency Virus Clinical Trials in the United States

BACKGROUND

Women are underrepresented in human immunodeficiency virus (HIV) research in the United States. To determine if women screening for HIV clinical trials enrolled at lower rates than men, we performed a retrospective, cross-trial analysis.

METHODS

We conducted an analysis of screening and enrollment during 2003-2013 to 31 clinical trials at 99 AIDS Clinical Trials Group network research sites in the United States. Random-effects meta regression estimated whether sex differences in not enrolling ("screen out") varied by various individual, trial, or site characteristics.

RESULTS

Of 10 744 persons screened, 18.9% were women. The percentages of women and men who screened out were 27.9% and 26.5%, respectively (P = .19); this small difference did not significantly vary by race, ethnicity, or age group. Most common reasons for screening out were not meeting eligibility criteria (30-35%) and opting out (23%), and these did not differ by sex. Trial and research site characteristics associated with variable screen-out by sex included HIV research domain and type of hemoglobin eligibility criterion, but individual associations did not persist after adjustment for multiple testing.

CONCLUSIONS

In the absence of evidence of significantly higher trial screen-out for women, approaching more women to screen may increase female representation in HIV trials.

HIV and women in the USA: what we know and where to go from here

New diagnoses of HIV infection have decreased among women in the USA overall, but marked racial and geographical disparities persist. The federal government has announced an initiative that aims to decrease the number of new infections in the nation by 90% within the next 10 years. With this in mind, we highlight important recent developments concerning HIV epidemiology, comorbidities, treatment, and prevention among women in the USA. We conclude that, to end the US HIV epidemic, substantially greater inclusion of US women in clinical research will be required, as will better prevention and treatment efforts, with universal access to health care and other supportive services that enable women to exercise agency in their own HIV prevention and care. Ending the epidemic will also require eliminating the race, class, and gender inequities, as well as the discrimination and structural violence, that have promoted and maintained the distribution of HIV in the USA, and that will, if unchecked, continue to fuel the epidemic in the future.

"I would really want to know that they had my back": Transgender women's perceptions of HIV cure-related research in the United States

Forty-four percent of Black transgender women are living with HIV, and many face challenges with HIV care engagement. An HIV cure has much to offer this population, however little HIV cure-related research has included them. We conducted 19 face-to-face in-depth interviews with 10 Black transgender women living with HIV. Interviews were audio recorded, transcribed verbatim, coded, and analyzed using content analysis. Our interview guide contained three categories: 1) perceptions of HIV cure-related research and participation, 2) perceptions of HIV treatment and treatment interruptions, and 3) considerations for transgender women and HIV cure-related research. Salient themes included skepticism about HIV cure strategies and limited benefits compared with an undetectable viral load. Willingness to interrupt HIV treatment for research was low and linked to being able to go back on the same HIV treatment without consequence when the study ended. Concerns about being a test subject and perceptions of risks versus benefits of various strategies also affected willingness to take part in HIV cure-related research. Centering the dignity and autonomy of research participants as well as building upon and supporting existing social networks were identified as important facilitators for engaging Black transgender women in HIV cure-related research. Specific to Black transgender women, other concerns included the desire for gender-affirming research staff, community-building among transgender women, and safety issues associated with risk of transphobic violence when traveling to study visits. Participants stressed the importance of HIV cure-related researchers providing accessible and complete information and expressing genuine care and concern for transgender communities.

A landscape analysis of HIV cure-related clinical research in 2019

Objectives

In 2018, we surveyed investigators conducting HIV cure-related clinical research, drawing on information from the online listing established by Treatment Action Group (TAG). The purpose of the survey was to facilitate a landscape analysis of the field. In 2019, we fielded a second survey in order to provide updated information and assess any shifts in the landscape.

Methods

Trials and observational studies listed as of August 16, 2019 formed the sample set. Survey questions addressed funding, trial development, recruitment, enrollment, participant demographics, antiretroviral therapy status, HIV reservoir assays, invasive procedures, study completion, data sharing and dissemination plans. A survey was sent to the contact(s) for each study. Supplemental information was collected from clinicaltrials.gov and available presentations/publications of study results.

Results

A total of 97 interventional trials and 36 observational studies were identified, with 30 including analytical treatment interruptions. Total projected enrollment is 13,732 participants, with observational studies contributing the majority (8,325). Most interventional trials are in early phases. The majority of current research is located in the USA, involves predominately male participants and is limited in racial and ethnic diversity. Prespecified demographic enrollment targets are rare. Two thirds of respondents to our previous survey reported that enrollment is progressing more slowly than anticipated.

Conclusions

A diverse range of interventions are being evaluated in HIV cure research, but participant diversity is far from optimal with a continuing underrepresentation of women. Broadening inclusion and geographic reach will be necessary to achieve the goal of developing widely effective, safe and accessible curative interventions.

Participant Perspectives in an HIV Cure-Related Trial Conducted Exclusively in Women in the United States: Results from AIDS Clinical Trials Group 5366

Women remain underrepresented in HIV research. The AIDS Clinical Trials Group (ACTG) 5366 study was the first HIV cure-related trial conducted exclusively in women. Our multidisciplinary team integrated participant-centered reports into the ACTG 5366 protocol to elicit their perspectives. We nested mixed-methods surveys at the enrollment and final study visits to assess ACTG 5366 participants' perceptions and experiences. Of 31 participants enrolled in the ACTG 5366, 29 study agreed to complete the entry questionnaire and 27 completed the exit survey. The majority of study participants were nonwhite. We identified societal and personal motivators for participation, understanding of risks and benefits, and minor misconceptions among some trial participants. Stigma was pervasive for several women who joined the study, and served as a motivator for study participation. Reimbursements to defray costs of study participation were reported to facilitate involvement in the trial by about one-third of participants. Almost all respondents reported positive experiences participating in the ACTG 5366 trial. The ACTG 5366 study showed that it is possible to recruit and retain women in HIV cure-related research and to embed participant-centered outcomes at strategic time points during the study. The findings could help in the design, implementation, recruitment, and retention of women in HIV cure-related research and highlight the value of assessing psychosocial factors in HIV cure-related research participation.

Differences in HIV cure clinical trial preferences of French people living with HIV and physicians in the ANRS-APSEC study: a discrete choice experiment

INTRODUCTION

Despite the advent of HIV cure-related clinical trials (HCRCT) for people living with HIV (PLWH), the risks and uncertainty involved raise ethical issues. Although research has provided insights into the levers and barriers to PLWH and physicians' participation in these trials, no information exists about stakeholders' preferences for HCRCT attributes, about the different ways PLWH and physicians value future HCRCT, or about how personal characteristics affect these preferences. The results from the present study will inform researchers' decisions about the most suitable HCRCT strategies to implement, and help them ensure ethical recruitment and well-designed informed consent.

METHODS

Between October 2016 and March 2017, a discrete choice experiment was conducted among 195 virally controlled PLWH and 160 physicians from 24 French HIV centres. Profiles within each group, based on individual characteristics, were obtained using hierarchical clustering. Trade-offs between five HCRCT attributes (trial duration, consultation frequency, moderate (digestive disorders, flu-type syndrome, fatigue) and severe (allergy, infections, risk of cancer) side effects (SE), outcomes) and utilities associated with four HCRCT candidates (latency reactivation, immunotherapy, gene therapy and a combination of latency reactivation and immunotherapy), were estimated using a mixed logit model.

RESULTS

Apart from severe SE - the most decisive attribute in both groups - PLWH and physicians made different trade-offs between HCRCT attributes, the latter being more concerned about outcomes, the former about the burden of participation (consultation frequency and moderate SE). These different trades-offs resulted in differences in preferences regarding the four candidate HCRCT. PLWH significantly preferred immunotherapy, whereas physicians preferred immunotherapy and combined therapy. Despite the heterogeneity of characteristics within the PLWH and physician profiles, results show some homogeneity in trade-offs and utilities regarding HCRCT.

CONCLUSIONS

Severe SE, not outcomes, was the most decisive attribute determining future HCRCT participation. Particular attention should be paid to providing clear information, in particular on severe SE, to potential participants. Immunotherapy would appear to be the best HCRCT candidate for both PLWH and physicians. However, if the risk of cancer could be avoided, gene therapy would become the preferred strategy for the latter and the second choice for the former.

Sex-Based Differences in Human Immunodeficiency Virus Type 1 Reservoir Activity and Residual Immune Activation

Plasma human immunodeficiency virus type 1 (HIV-1) RNA levels in women are lower early in untreated HIV-1 infection compared with those in men, but women have higher T-cell activation and faster disease progression when adjusted for viral load. It is not known whether these sex differences persist during effective antiretroviral therapy (ART), or whether they would be relevant for the evaluation and implementation of HIV-1 cure strategies. We prospectively enrolled a cohort of reproductive-aged women and matched men on suppressive ART and measured markers of HIV-1 persistence, residual virus activity, and immune activation. The frequency of CD4+ T cells harboring HIV-1 DNA was comparable between the sexes, but there was higher cell-associated HIV-1 RNA, higher plasma HIV-1 (single copy assay), and higher T-cell activation and PD-1 expression in men compared with women. These sex-related differences in immune phenotype and HIV-1 persistence on ART have significant implications for the design and measurement of curative interventions.

A landscape analysis of HIV cure-related clinical trials and observational studies in 2018

OBJECTIVES

The community-based organisation Treatment Action Group has established an online listing of HIV cure-related trials and observational studies derived from trial registries. Our objective was to use the listing as a basis for a landscape analysis of the current status of HIV cure-related clinical research.

METHODS

Trials and observational studies listed as of August 2018 formed the sample set. Survey questions were developed on trial development, trial design, recruitment, enrolment, study completion and dissemination plans. A survey was sent to the contact(s) for each study. Supplemental information was collected from clinicaltrials.gov. The full dataset was then analysed.

RESULTS

A total of 99 interventional trials and 29 observational studies were included. Diverse interventions are under evaluation, including combinations of experimental candidates. Current studies plan to enrol over 7000 participants. Projected completion dates for ~90% of the sample fell between the fourth quarter of 2018 and the end of 2020. Potential obstacles to enrolment that were reported included concerns over invasive procedures and lack of potential benefit to participants. Data on the sex and ethnicity of enrollees were limited but sufficient to note a significant under-representation of women.

CONCLUSIONS

A considerable amount of HIV cure-related clinical research is under way. The results from these studies, which should help shape the future of the field, will become available over the next 2-4 years. Diversity both geographically and in terms of enrollees remains limited, particularly in terms of the participation of women, a concern that could significantly affect the generalisability of the findings.

Gender differences in innate responses and gene expression profiles in memory CD4 T cells are apparent very early during acute simian immunodeficiency virus infection

Gender differences in Human immunodeficiency virus (HIV) disease progression and comorbidities have been extensively reported. Using the simian immunodeficiency virus (SIV) infected rhesus macaque model, we show that these differences are apparent very early during the course of infection. Though there were no major changes in the proportions of CD4 T cells or its subsets, central memory CD4 T cells from female macaques were found to differentially regulate a significantly larger number of genes at day 4 post-infection (PI) as compared to males. Pathway analysis revealed divergence of both canonical and biological pathways that persisted at day 10 PI. Changes in gene expression profiles were accompanied by a significant increase in plasma levels of pro-inflammatory mediators such as MCP-1/CCL2, I-TAC/CXCL11, and MIF. Though plasma levels of IFNα did not differ between male and female macaques, the expression levels of IFNα subtype-14, 16, IFNβ, and IFNω were significantly upregulated in the lymph nodes of female macaques at day 10 PI as compared to male macaques. Our results suggest that the pathogenic sequelae seen during chronic infection may be shaped by gender differences in immune responses induced very early during the course of HIV infection.

Recommendations for analytical antiretroviral treatment interruptions in HIV research trials-report of a consensus meeting

Analytical antiretroviral treatment interruption (ATI) is an important feature of HIV research, seeking to achieve sustained viral suppression in the absence of antiretroviral therapy (ART) when the goal is to measure effects of novel therapeutic interventions on time to viral load rebound or altered viral setpoint. Trials with ATIs also intend to determine host, virological, and immunological markers that are predictive of sustained viral control off ART. Although ATI is increasingly incorporated into proof-of-concept trials, no consensus has been reached on strategies to maximise its utility and minimise its risks. In addition, differences in ATI trial designs hinder the ability to compare efficacy and safety of interventions across trials. Therefore, we held a meeting of stakeholders from many interest groups, including scientists, clinicians, ethicists, social scientists, regulators, people living with HIV, and advocacy groups, to discuss the main challenges concerning ATI studies and to formulate recommendations with an emphasis on strategies for risk mitigation and monitoring, ART resumption criteria, and ethical considerations. In this Review, we present the major points of discussion and consensus views achieved with the goal of informing the conduct of ATIs to maximise the knowledge gained and minimise the risk to participants in clinical HIV research.

Revisiting the 'sterilising cure' terminology: a call for more patient-centred perspectives on HIV cure-related research

The literature on HIV therapeutics research is rife with terminology associating 'sterilisation' with HIV cure. We find connotations of the word 'sterilising' problematic for the HIV cure research field. In this viewpoint, we review associations of sterilising with concepts of disinfection or cleansing, as well as coerced sterilisation. We discuss emerging findings from socio-behavioural research that show aversion from people living with HIV towards the 'sterilising cure' nomenclature. We call for more collaborations with people with HIV as partners to help define what would be a more acceptable terminology for describing an HIV cure.

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.

Analysis of Complement-Mediated Lysis of Simian Immunodeficiency Virus (SIV) and SIV-Infected Cells Reveals Sex Differences in Vaccine-Induced Immune Responses in Rhesus Macaques

An effective human immunodeficiency virus (HIV) vaccine has yet to be developed, and defining immune correlates of protection against HIV infection is of paramount importance to inform future vaccine design. The complement system is a component of innate immunity that can directly lyse pathogens and shape adaptive immunity. To determine if complement lysis of simian immunodeficiency virus (SIV) and/or SIV-infected cells represents a protective immune correlate against SIV infection, sera from previously vaccinated and challenged rhesus macaques were analyzed for the induction of antibody-dependent complement-mediated lysis (ADCML). Importantly, the vaccine regimen, consisting of a replication-competent adenovirus type 5 host-range mutant SIV recombinant prime followed by a monomeric gp120 or oligomeric gp140 boost, resulted in overall delayed SIV acquisition only in females. Here, sera from all vaccinated animals induced ADCML of SIV and SIV-infected cells efficiently, regardless of sex. A modest correlation of SIV lysis with a reduced infection rate in males but not females, together with a reduced peak viremia in all animals boosted with gp140, suggested a potential for influencing protective efficacy. Gag-specific IgG and gp120-specific IgG and IgM correlated with SIV lysis in females, while Env-specific IgM correlated with SIV-infected cell lysis in males, indicating sex differences in vaccine-induced antibody characteristics and function. In fact, gp120/gp140-specific antibody functional correlates between antibody-dependent cellular cytotoxicity, antibody-dependent phagocytosis, and ADCML as well as the gp120-specific IgG glycan profiles and the corresponding ADCML correlations varied depending on the sex of the vaccinees. Overall, these data suggest that sex influences vaccine-induced antibody function, which should be considered in the design of globally effective HIV vaccines in the future.IMPORTANCE An HIV vaccine would thwart the spread of HIV infection and save millions of lives. Unfortunately, the immune responses conferring universal protection from HIV infection are poorly defined. The innate immune system, including the complement system, is an evolutionarily conserved, basic means of protection from infection. Complement can prevent infection by directly lysing incoming pathogens. We found that vaccination against SIV in rhesus macaques induces antibodies that are capable of directing complement lysis of SIV and SIV-infected cells in both sexes. We also found sex differences in vaccine-induced antibody species and their functions. Overall, our data suggest that sex affects vaccine-induced antibody characteristics and function and that males and females might require different immune responses to protect against HIV infection. This information could be used to generate highly effective HIV vaccines for both sexes in the future.

Research on HIV cure: Mapping the ethics landscape

In an essay, Karine Dubé and coauthors discuss the ethics of preclinical and clinical studies relevant to achieving an HIV cure.

Barriers to HIV remission research in low- and middle-income countries

INTRODUCTION

HIV eradication and remission research has largely taken place in high-income countries. In low- and middle-income countries (LMIC), there may be factors that have a substantial impact on the size of the latent HIV reservoir and the immunological response to infection. If a curative strategy is to be available to all HIV-infected individuals, these factors must be understood.

METHODS

We use a scoping review to examine the literature on biological factors that may have an impact on HIV persistence in LMIC. Three databases were searched without date restrictions.

RESULTS

Uncontrolled viral replication and higher coinfection prevalence may alter the immunological milieu of individuals in LMIC and increase the size of the HIV reservoir. Differences in HIV subtype could also influence the measurement and size of the HIV reservoir. Immune activation may differ due to late presentation to care, presence of chronic infections, increased gut translocation of bacterial products and poor nutrition.

CONCLUSIONS

Research on HIV remission is urgently needed in LMIC. Research into chronic immune activation in resource poor environments, the immune response to infection, the mechanisms of HIV persistence and latency in different viral clades and the effect of the microbiological milieu must be performed. Geographic differences, which may be substantial and may delay access to curative strategies, should be identified.