How Unavoidable Are Analytical Treatment Interruptions in HIV Cure-Related Studies?

A partner protection package for HIV cure-related trials involving analytical treatment interruptions

Analytical treatment interruptions (ATIs) have become a key methodological approach to evaluate the effects of experimental HIV cure-related research interventions. During ATIs, sex partners of trial participants might be at risk of acquiring HIV. This risk raises both ethical and feasibility concerns about ATI trials. We propose a partner protection package (P3) approach to address these concerns. A P3 approach would provide guidance to investigators, sponsors, and those who are designing and implementing context-specific partner protections in HIV cure-related trials involving ATIs. The approach would also help assure institutional review boards, trial participants, and communities that ATI trials with a P3 would provide appropriate partner protections. We offer a prototype P3 framework that delineates three basic considerations for protecting participants' sex partners during ATI trials: (1) ensuring the scientific and social value of the ATI and the trial, (2) reducing the likelihood of unintended HIV transmission, and (3) ensuring prompt management of any acquired HIV infection. We outline possible ways of implementing these basic considerations.

Prolonged viral suppression with anti-HIV-1 antibody therapy

HIV-1 infection remains a public health problem with no cure. Anti-retroviral therapy (ART) is effective but requires lifelong drug administration owing to a stable reservoir of latent proviruses integrated into the genome of CD4+ T cells1. Immunotherapy with anti-HIV-1 antibodies has the potential to suppress infection and increase the rate of clearance of infected cells2,3. Here we report on a clinical study in which people living with HIV received seven doses of a combination of two broadly neutralizing antibodies over 20 weeks in the presence or absence of ART. Without pre-screening for antibody sensitivity, 76% (13 out of 17) of the volunteers maintained virologic suppression for at least 20 weeks off ART. Post hoc sensitivity analyses were not predictive of the time to viral rebound. Individuals in whom virus remained suppressed for more than 20 weeks showed rebound viraemia after one of the antibodies reached serum concentrations below 10 µg ml-1. Two of the individuals who received all seven antibody doses maintained suppression after one year. Reservoir analysis performed after six months of antibody therapy revealed changes in the size and composition of the intact proviral reservoir. By contrast, there was no measurable decrease in the defective reservoir in the same individuals. These data suggest that antibody administration affects the HIV-1 reservoir, but additional larger and longer studies will be required to define the precise effect of antibody immunotherapy on the reservoir.

Participant Perspectives and Experiences Following an Intensively Monitored Antiretroviral Pause in the United States: Results from the AIDS Clinical Trials Group A5345 Biomarker Study

The AIDS Clinical Trials Group A5345 study (NCT03001128) included an intensively monitored antiretroviral pause (IMAP), during which participants living with HIV temporarily stopped antiretroviral treatment (ART) in an effort to identify biomarkers that could predict HIV rebound. We evaluated the potential impact of the IMAP on A5345 study participants in the United States by questioning them immediately after the IMAP and at the end of the study. We administered longitudinal sociobehavioral questionnaires to participants following the IMAP when they resumed ART and at the end of the study. We summarized descriptive data from the post-IMAP and end-of-study questionnaires. Open-ended responses were analyzed using conventional content analysis. Reactions to pausing ART involved a mixture of curiosity and satisfaction from contributing to science. All participants indicated adherence with the ART interruption. About half (9/17) of post-IMAP questionnaire respondents reported having sexual partner(s) during the IMAP, and of those, nearly all (8/9) did not find it difficult to use measures to prevent HIV transmission to partners. The majority believed that they benefited from the study, yet some had elevated anxiety following the IMAP and at the end of the study. Most (24/29) respondents who completed the end-of-study questionnaire would recommend the study to other people living with HIV. Our findings underscore the relevance of the psychosocial aspects of participating in studies that involve interruptions of ART. Understanding how participants experience this research is invaluable for informing the design of future research aimed at sustained ART-free virologic suppression.

OUP accepted manuscript

Background

Methods

Results

Conclusions

Ethical considerations for HIV remission clinical research involving participants diagnosed during acute HIV infection

HIV remission clinical researchers are increasingly seeking study participants who are diagnosed and treated during acute HIV infection—the brief period between infection and the point when the body creates detectable HIV antibodies. This earliest stage of infection is often marked by flu-like illness and may be an especially tumultuous period of confusion, guilt, anger, and uncertainty. Such experiences may present added ethical challenges for HIV research recruitment, participation, and retention. The purpose of this paper is to identify potential ethical challenges associated with involving acutely diagnosed people living with HIV in remission research and considerations for how to mitigate them. We identify three domains of potential ethical concern for clinicians, researchers, and ethics committee members to consider: 1) Recruitment and informed consent; (2) Transmission risks and partner protection; and (3) Ancillary and continuing care. We discuss each of these domains with the aim of inspiring further work to advance the ethical conduct of HIV remission research. For example, experiences of confusion and uncertainty regarding illness and diagnosis during acute HIV infection may complicate informed consent procedures in studies that seek to recruit directly after diagnosis. To address this, it may be appropriate to use staged re-consent procedures or comprehension assessment. Responsible conduct of research requires a broad understanding of acute HIV infection that encompasses its biomedical, psychological, social, and behavioral dimensions. We argue that the lived experience of acute HIV infection may introduce ethical concerns that researchers and reviewers should address during study design and ethical approval.

Participant Perspectives and Experiences Entering an Intensively Monitored Antiretroviral Pause: Results from the AIDS Clinical Trials Group A5345 Biomarker Study

The AIDS Clinical Trials Group (ACTG) A5345 study included an intensively monitored antiretroviral pause (IMAP), during which a cohort of participants temporarily stopped antiretroviral treatment during chronic HIV infection. We surveyed participant perceptions and understanding of A5345 using a cross-sectional sociobehavioral questionnaire. Participants completed the baseline questionnaire either before or after initiating the study's IMAP. Questionnaire responses were linked to existing demographic data. Quantitative responses were analyzed overall and stratified by IMAP status. Open-ended responses were analyzed using conventional content analysis. Thirty-two participants completed the baseline sociobehavioral questionnaire. Half (n = 16) completed it before (i.e., pre-IMAP initiation group) and half (n = 16) after IMAP initiation (i.e., post-IMAP initiation group). Eight pre-IMAP initiation respondents (50%) and 11 post-IMAP respondents (69%) responded "yes" when asked if they perceived any direct benefits from participating in A5345. Perceived societal-level benefits included furthering HIV cure-related research and helping the HIV community. Perceived personal-level benefits included the opportunity to learn about the body's response to IMAP and financial compensation. The majority of respondents-13 from each group (81% of each)-reported risks from participation, for example, viral load becoming detectable. A5345 participants perceived both societal- and personal-level benefits of study participation. While the majority of survey respondents perceived participatory risks, nearly one in five did not. Key messages pertaining to study-related risks and benefits may need to be clarified or reiterated periodically throughout follow-up in HIV cure-related studies with IMAPs. Clinical Trail Registration Number: NCT03001128.

Transient viral replication during analytical treatment interruptions in SIV infected macaques can alter the rebound-competent viral reservoir

Analytical treatment interruptions (ATIs) of antiretroviral therapy (ART) play a central role in evaluating the efficacy of HIV-1 treatment strategies targeting virus that persists despite ART. However, it remains unclear if ATIs alter the rebound-competent viral reservoir (RCVR), the virus population that persists during ART and from which viral recrudescence originates after ART discontinuation. To assess the impact of ATIs on the RCVR, we used a barcode sequence tagged SIV to track individual viral lineages through a series of ATIs in Rhesus macaques. We demonstrate that transient replication of individual rebounding lineages during an ATI can lead to their enrichment in the RCVR, increasing their probability of reactivating again after treatment discontinuation. These data establish that the RCVR can be altered by uncontrolled replication during ATI.

Operationalizing Human Immunodeficiency Virus Cure-related Trials with Analytic Treatment Interruptions During the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Pandemic: A Collaborative Approach

Efforts to recognize and minimize the risk to study participants will be necessary to safely and ethically resume scientific research in the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. These efforts are uniquely challenging in the context of human immunodeficiency virus (HIV) cure clinical trials, which often involve complex experimental therapy regimens and perhaps analytic treatment interruption, in which participants pause antiretroviral therapy. In this viewpoint, we discuss our approach to reopening an HIV cure trial in this context, with a focus on key considerations regarding study design, informed consent and participant education, and study implementation. These recommendations might be informative to other groups seeking to resume HIV cure research in settings similar to ours.

Unwillingness of patients in Ghana to interrupt antiretroviral therapy for HIV cure research

Objectives

Though antiretroviral therapy (ART) has reduced HIV infection into a manageable chronic disease, it does not provide for a cure. HIV cure trials may carry risks for patients who are generally doing well on ART, making it imperative that their input is sought as various types of cure methods and trials are designed. Few studies have sought the views of African patients on HIV cure studies. The objective of this study was to determine the views and preferences of people living with HIV (PLWH) in Ghana on cure research.

Methods

We used a questionnaire to interview 251 PLWH in Ghana about their willingness to engage in HIV cure research. We investigated their motivations, the types of cure they would prefer and which risks were acceptable to them.

Results

Most participants were enthusiastic about participating in cure research and driven by both altruistic and personal motives. Patients preferred a cure where they would continue follow-up with their doctor (88%) compared to being assured that they have been completely cured and did not need further follow-up (11%). The vast majority of the respondents were risk averse. Most patients (67%) would decline to interrupt ART as part of a protocol for HIV cure research. In bivariate analysis, participants above the age of 40 years were more likely to agree to treatment interruption during cure studies (OR 2.77; 95% CI 1.21-.6.34. p ​= ​0.0159).

Conclusions

Our results show that preferred cure modalities and risk tolerance for patients in Africa may be different from those of other parts of the world. Extensive social science and behavioural studies are needed on the continent to help inform future cure trials.

Novel Approaches Towards a Functional Cure of HIV/AIDS

Therapeutic approaches towards a functional cure or eradication of HIV have gained renewed momentum upon encouraging data emerging from studies in SIV monkey models and recent results from human clinical studies. However, a multitude of questions remain to be addressed, including how to deal with the latent viral reservoir, how to boost the host immune response to the virus and what the hurdles are to reach relevant viral compartments in the body. Advances have been made especially with regard to identifying agents that can reactivate the latent virus in vivo and boost the cellular and humoral immunity, but it remains largely unclear whether any of these strategies can awaken a sufficiently large fraction of the viral reservoir and whether the boosted immunity can prevent rapid viral replication once antiretroviral treatments are stopped.

A collaborative, multidisciplinary approach to HIV transmission risk mitigation during analytic treatment interruption

Analytic treatment interruptions (ATIs) are currently the standard for assessing the impact of experimental interventions aimed at inducing sustained antiretroviral therapy (ART)-free remission in trials related to HIV cure. ATIs are associated with substantial risk to both study participants and their sexual partner(s). Two documented HIV transmissions occurring in the context of ATIs have been recently reported, but recommendations for mitigating the risk of such events during ATIs are limited. We outline a practical approach to risk mitigation during ATI studies and describe strategies we are utilising in an upcoming clinical trial that may be applicable to other centres.

Predictors of SIV recrudescence following antiretroviral treatment interruption

There is currently a need for proxy measures of the HIV rebound competent reservoir (RCR) that can predict viral rebound after combined antiretroviral treatment (cART) interruption. In this study, macaques infected with a barcoded SIVmac239 virus received cART beginning between 4- and 27 days post-infection, leading to the establishment of different levels of viral dissemination and persistence. Later treatment initiation led to higher SIV DNA levels maintained during treatment, which was significantly associated with an increased frequency of SIV reactivation and production of progeny capable of causing rebound viremia following treatment interruption. However, a 100-fold increase in SIV DNA in PBMCs was associated with only a 2-fold increase in the frequency of reactivation. These data suggest that the RCR can be established soon after infection, and that a large fraction of persistent viral DNA that accumulates after this time makes relatively little contribution to viral rebound.