Antiretroviral therapy in acute and recent HIV infection: a prospective multicenter stratified trial of intentionally interrupted treatment

Understanding early HIV-1 rebound dynamics following antiretroviral therapy interruption: The importance of effector cell expansion

Most people living with HIV-1 experience rapid viral rebound once antiretroviral therapy is interrupted; however, a small fraction remain in viral remission for an extended duration. Understanding the factors that determine whether viral rebound is likely after treatment interruption can enable the development of optimal treatment regimens and therapeutic interventions to potentially achieve a functional cure for HIV-1. We built upon the theoretical framework proposed by Conway and Perelson to construct dynamic models of virus-immune interactions to study factors that influence viral rebound dynamics. We evaluated these models using viral load data from 24 individuals following antiretroviral therapy interruption. The best-performing model accurately captures the heterogeneity of viral dynamics and highlights the importance of the effector cell expansion rate. Our results show that post-treatment controllers and non-controllers can be distinguished based on the effector cell expansion rate in our models. Furthermore, these results demonstrate the potential of using dynamic models incorporating an effector cell response to understand early viral rebound dynamics post-antiretroviral therapy interruption.

Understanding early HIV-1 rebound dynamics following antiretroviral therapy interruption: The importance of effector cell expansion

Most people living with HIV-1 experience rapid viral rebound once antiretroviral therapy is interrupted; however, a small fraction remain in viral remission for an extended duration. Understanding the factors that determine whether viral rebound is likely after treatment interruption can enable the development of optimal treatment regimens and therapeutic interventions to potentially achieve a functional cure for HIV-1. We built upon the theoretical framework proposed by Conway and Perelson to construct dynamic models of virus-immune interactions to study factors that influence viral rebound dynamics. We evaluated these models using viral load data from 24 individuals following antiretroviral therapy interruption. The best-performing model accurately captures the heterogeneity of viral dynamics and highlights the importance of the effector cell expansion rate. Our results show that post-treatment controllers and non-controllers can be distinguished based on the effector cell expansion rate in our models. Furthermore, these results demonstrate the potential of using dynamic models incorporating an effector cell response to understand early viral rebound dynamics post-antiretroviral therapy interruption.

Demographics of Youth With Newly Diagnosed Acute/Recent HIV Infection in Adolescent Trials Network 147: Early Treatment of Acute HIV Infection

PURPOSE

Gay, bisexual, and other cisgender men who have sex with men, and racial minority youth are at elevated risk of acquiring HIV infection. The Adolescent Trials Network 147 recruited youth with acute/recent HIV-infection for early antiretroviral treatment. The cohort make-up is described here.

METHODS

Treatment-naïve, recently identified HIV + youth, aged 12-24 years, from Los Angeles and New Orleans were recruited from community centers, clinics, social media, and a high-risk seronegative cohort (n = 1,727, the Adolescent Trials Network 149) using point-of-care assays. Acute HIV infection was determined by Fiebig staging. HIV RNA viral load (VL) and CD4 cell counts, along with demographic and behavioral data were assessed at enrollment.

RESULTS

Between July 2017 and July 2021, 103 newly diagnosed youth were enrolled, initiating antiretroviral treatment within a week. Mean age was 20.8 years (standard deviation: 2.4); 90.3% identified as cis male, 83.5% were single or in casual relationships, 71.8% were gay, bisexual, and other cisgender men who have sex with men; 60.2% were Black. One-fourth (24.3%) reported homelessness ever; 10.7% within last 4 months. At enrollment, median plasma VL was 37,313 HIV RNA copies/ml (interquartile range: 5,849-126,162) and median CD4 count 445.5 cells/mm3 (interquartile range: 357-613). 40% of youth reported acute retroviral symptoms before or at enrollment. Acutely infected, seroconverting youth had the highest VL. Sexually transmitted coinfections were present at enrollment in 56% of the cohort, with syphilis being most frequent (39%).

DISCUSSION

Early identification and treatment of HIV can increase positive HIV outcomes. A high sexually transmitted infection burden was present in recently HIV-infected youth. Acute retroviral symptoms were not reported by most participants, demonstrating that broad universal HIV screening is needed for identification of recent infection in youth.

Smoothed simulated pseudo-maximum likelihood estimation for nonlinear mixed effects models with censored responses

Nonlinear mixed effects models have been widely applied to analyses of data that arise from biological, agricultural, and environmental sciences. Estimation of and inference on parameters in nonlinear mixed effects models are often based on the specification of a likelihood function. Maximizing this likelihood function can be complicated by the specification of the random effects distribution, especially in the presence of multiple random effects. The implementation of nonlinear mixed effects models can be further complicated by left-censored responses, representing measurements from bioassays where the exact quantification below a certain threshold is not possible. Motivated by the need to characterize the nonlinear human immunodeficiency virus RNA viral load trajectories after the interruption of antiretroviral therapy, we propose a smoothed simulated pseudo-maximum likelihood estimation approach to fit nonlinear mixed effects models in the presence of left-censored observations. We establish the consistency and asymptotic normality of the resulting estimators. We develop testing procedures for the correlation among random effects and for testing the distributional assumptions on random effects against a specific alternative. In contrast to the existing variants of expectation-maximization approaches, the proposed methods offer flexibility in the specification of the random effects distribution and convenience in making inference about higher-order correlation parameters. We evaluate the finite-sample performance of the proposed methods through extensive simulation studies and illustrate them on a combined dataset from six AIDS Clinical Trials Group treatment interruption studies.

Autologous neutralizing antibodies increase with early antiretroviral therapy and shape HIV rebound after treatment interruption

Early initiation of antiretroviral therapy (ART) alters viral rebound kinetics after analytic treatment interruption (ATI) and may play a role in promoting HIV-1 remission. Autologous neutralizing antibodies (aNAbs) represent a key adaptive immune response in people living with HIV-1. We aimed to investigate the role of aNAbs in shaping post-ATI HIV-1 rebound variants. We performed single-genome amplification of HIV-1 env from pre-ART and post-ATI plasma samples of 12 individuals who initiated ART early after infection. aNAb activity was quantified using pseudoviruses derived from the most common plasma variant, and the serum dilution that inhibited 50% of viral infections was determined. aNAb responses matured while participants were on suppressive ART, because on-ART plasma and purified immunoglobulin G (IgG) demonstrated improved neutralizing activity against pre-ART HIV-1 strains when compared with pre-ART plasma or purified IgG. Post-ATI aNAb responses exerted selective pressure on the rebounding viruses, because the post-ATI HIV-1 strains were more resistant to post-ATI plasma neutralization compared with the pre-ART virus. Several pre-ATI features distinguished post-treatment controllers from noncontrollers, including an infecting HIV-1 sequence that was more similar to consensus HIV-1 subtype B, more restricted proviral diversity, and a stronger aNAb response. Post-treatment control was also associated with the evolution of distinct N-glycosylation profiles in the HIV-1 envelope. In summary, aNAb responses appeared to mature after early initiation of ART and applied selective pressure on rebounding viruses. The combination of aNAb activity with select HIV-1 sequence and reservoir features identified individuals with a greater chance of post-treatment control.

HIV post-treatment controllers have distinct immunological and virological features

HIV post-treatment controllers (PTCs) are rare individuals who maintain low levels of viremia after stopping antiretroviral therapy (ART). Understanding the mechanisms of HIV post-treatment control will inform development of strategies aiming at achieving HIV functional cure. In this study, we evaluated 22 PTCs from 8 AIDS Clinical Trials Group (ACTG) analytical treatment interruption (ATI) studies who maintained viral loads ≤400 copies/mL for ≥24 wk. There were no significant differences in demographics or frequency of protective and susceptible human leukocyte antigen (HLA) alleles between PTCs and post-treatment noncontrollers (NCs, n = 37). Unlike NCs, PTCs demonstrated a stable HIV reservoir measured by cell-associated RNA (CA-RNA) and intact proviral DNA assay (IPDA) during analytical treatment interruption (ATI). Immunologically, PTCs demonstrated significantly lower CD4+ and CD8+ T cell activation, lower CD4+ T cell exhaustion, and more robust Gag-specific CD4+ T cell responses and natural killer (NK) cell responses. Sparse partial least squares discriminant analysis (sPLS-DA) identified a set of features enriched in PTCs, including a higher CD4+ T cell% and CD4+/CD8+ ratio, more functional NK cells, and a lower CD4+ T cell exhaustion level. These results provide insights into the key viral reservoir features and immunological profiles for HIV PTCs and have implications for future studies evaluating interventions to achieve an HIV functional cure.

Transcriptomic Signatures of Human Immunodeficiency Virus Post-Treatment Control

Posttreatment controllers (PTCs) are rare HIV-infected individuals who can limit viral rebound after antiretroviral therapy interruption (ATI), but the mechanisms of this remain unclear. To investigate these mechanisms, we quantified various HIV RNA transcripts (via reverse transcription droplet digital PCR [RT-ddPCR]) and cellular transcriptomes (via RNA-seq) in blood cells from PTCs and noncontrollers (NCs) before and two time points after ATI. HIV transcription initiation did not significantly increase after ATI in PTCs or in NCs, whereas completed HIV transcripts increased at early ATI in both groups and multiply-spliced HIV transcripts increased only in NCs. Compared to NCs, PTCs showed lower levels of HIV DNA, more cell-associated HIV transcripts per total RNA at all times, no increase in multiply-spliced HIV RNA at early or late ATI, and a reduction in the ratio of completed/elongated HIV RNA after early ATI. NCs expressed higher levels of the IL-7 pathway before ATI and expressed higher levels of multiple cytokine, inflammation, HIV transcription, and cell death pathways after ATI. Compared to the baseline, the NCs upregulated interferon and cytokine (especially TNF) pathways during early and late ATI, whereas PTCs upregulated interferon and p53 pathways only at early ATI and downregulated gene translation during early and late ATI. In NCs, viral rebound after ATI is associated with increases in HIV transcriptional completion and splicing, rather than initiation. Differences in HIV and cellular transcription may contribute to posttreatment control, including an early limitation of spliced HIV RNA, a delayed reduction in completed HIV transcripts, and the differential expression of the IL-7, p53, and TNF pathways. IMPORTANCE The findings presented here provide new insights into how HIV and cellular gene expression change after stopping ART in both noncontrollers and posttreatment controllers. Posttreatment control is associated with an early ability to limit increases in multiply-spliced HIV RNA, a delayed (and presumably immune-mediated) ability to reverse an initial rise in processive/completed HIV transcripts, and multiple differences in cellular gene expression pathways. These differences may represent correlates or mechanisms of posttreatment control and may provide insight into the development and/or monitoring of therapeutic strategies that are aimed at a functional HIV cure.

Acute HIV-1 infection viremia associate with rebound upon treatment interruption

BACKGROUND

Analytic treatment interruption (ATI) studies evaluate strategies to potentially induce remission in people living with HIV-1 but are often limited in sample size. We combined data from four studies that tested three interventions (vorinostat/hydroxychloroquine/maraviroc before ATI, Ad26/MVA vaccination before ATI, and VRC01 antibody infusion during ATI).

METHODS

The statistical validity of combining data from these participants was evaluated. Eleven variables, including HIV-1 viral load at diagnosis, Fiebig stage, and CD4+ T cell count were evaluated using pairwise correlations, statistical tests, and Cox survival models.

FINDINGS

Participants had homogeneous demographic and clinical characteristics. Because an antiviral effect was seen in participants who received VRC01 infusion post-ATI, these participants were excluded from the analysis, permitting a pooled analysis of 53 participants. Time to viral rebound was significantly associated with variables measured at the beginning of infection: pre-antiretroviral therapy (ART) viral load (HR = 1.34, p = 0.022), time to viral suppression post-ART initiation (HR = 1.07, p < 0.001), and area under the viral load curve (HR = 1.34, p = 0.026).

CONCLUSIONS

We show that higher viral loads in acute HIV-1 infection were associated with faster viral rebound, demonstrating that the initial stage of HIV-1 infection before ART initiation has a strong impact on viral rebound post-ATI years later.

FUNDING

This work was supported by a cooperative agreement between the Henry M. Jackson Foundation for the Advancement of Military Medicine and the US Department of the Army (W81XWH-18-2-0040). This research was funded, in part, by the US National Institute of Allergy and Infectious Diseases (AAI20052001) and the I4C Martin Delaney Collaboratory (5UM1AI126603-05).

Imaging and biopsy of HIV-infected individuals undergoing analytic treatment interruption

Background

HIV persistence during antiretroviral therapy (ART) is the principal obstacle to cure. Lymphoid tissue is a compartment for HIV, but mechanisms of persistence during ART and viral rebound when ART is interrupted are inadequately understood. Metabolic activity in lymphoid tissue of patients on long-term ART is relatively low, and increases when ART is stopped. Increases in metabolic activity can be detected by ¹⁸F-fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and may represent sites of HIV replication or immune activation in response to HIV replication.

Methods

FDG-PET imaging will be used to identify areas of high and low metabolic uptake in lymphoid tissue of individuals undergoing long-term ART. Baseline tissue samples will be collected. Participants will then be randomized 1:1 to continue or interrupt ART via analytic treatment interruption (ATI). Image-guided biopsy will be repeated 10 days after ATI initiation. After ART restart criteria are met, image-guided biopsy will be repeated once viral suppression is re-achieved. Participants who continued ART will have a second FDG-PET and biopsies 12–16 weeks after the first. Genetic characteristics of HIV populations in areas of high and low FDG uptake will be assesed. Optional assessments of non-lymphoid anatomic compartments may be performed to evaluate HIV populations in distinct anatomic compartments.

Anticipated results

We anticipate that PET standardized uptake values (SUV) will correlate with HIV viral RNA in biopsies of those regions and that lymph nodes with high SUV will have more viral RNA than those with low SUV within a patient. Individuals who undergo ATI are expected to have diverse viral populations upon viral rebound in lymphoid tissue. HIV populations in tissues may initially be phylogenetically diverse after ATI, with emergence of dominant viral species (clone) over time in plasma. Dominant viral species may represent the same HIV population seen before ATI.

Discussion

This study will allow us to explore utility of PET for identification of HIV infected cells and determine whether high FDG uptake respresents areas of HIV replication, immune activation or both. We will also characterize HIV infected cell populations in different anatomic locations. The protocol will represent a platform to investigate persistence and agents that may target HIV populations.

Study protocol registration

Identifier: NCT05419024.

Frequency of post treatment control varies by antiretroviral therapy restart and viral load criteria

Clinical trials including an analytical treatment interruption (ATI) are vital for evaluating the efficacy of novel strategies for HIV remissions. We briefly describe an interactive tool for predicting viral rebound timing in ATI trials and the impact of posttreatment controller (PTC) definitions on PTC frequency estimates. A 4-week viral load threshold of 1000 cps/ml provides both high specificity and sensitivity for PTC detection. PTC frequency varies greatly based on the definition of a PTC.

Impact of Analytical Treatment Interruption on Burden and Diversification of HIV Peripheral Reservoir: A Pilot Study

BACKGROUND

If analytical antiretroviral-treatment (ART) interruption (ATI) might significantly impact quantitative or qualitative peripheral-total HIV-DNA is still debated.

METHODS

Six chronically HIV-1 infected patients enrolled in APACHE-study were analysed for peripheral-total HIV-DNA and residual viremia, major-resistance-mutations (MRMs) and C2-V3-C3 evolution at pre-ATI (T1), during ATI (T2) and at achievement of virological success after ART-resumption (post-ATI, T3). These data were obtained at three comparable time-points in five chronically HIV-1 infected patients on suppressive ART for ≥1 year, enrolled in MODAt-study.

RESULTS

At T1, APACHE and MODAt individuals had similar peripheral-total HIV-DNA and residual viremia (p = 0.792 and 0.662, respectively), and no significant changes for these parameters were observed between T1 and T3 in both groups. At T1, 4/6 APACHE and 2/5 MODAt carried HIV-DNA MRMs. MRMs disappeared at T3 in 3/4 APACHE. All disappearing MRMs were characterized by T1 intra-patient prevalence <80%, and mainly occurred in APOBEC3-related sites. All MRMs persisted over-time in the 2 MODAt. C2-V3-C3 genetic-distance significantly changed from T1 to T3 in APACHE individuals (+0.36[0.11-0.41], p = 0.04), while no significant changes were found in MODAt. Accordingly, maximum likelihood trees (bootstrap > 70%) and genealogical sorting indices (GSI > 0.50 with p-value < 0.05) showed that T1 C2-V3-C3 DNA sequences were distinct from T2 and T3 viruses in 4/6 APACHE. Virus populations at all three time-points were highly interspersed in MODAt.

CONCLUSIONS

This pilot study indicates that short ATI does not alter peripheral-total HIV-DNA burden and residual viremia, but in some cases could cause a genetic diversification of peripheral viral reservoir in term of both MRMs rearrangement and viral evolution.

Non-invasive plasma glycomic and metabolic biomarkers of post-treatment control of HIV

Non-invasive biomarkers that predict HIV remission after antiretroviral therapy (ART) interruption are urgently needed. Such biomarkers can improve the safety of analytic treatment interruption (ATI) and provide mechanistic insights into the host pathways involved in post-ART HIV control. Here we report plasma glycomic and metabolic signatures of time-to-viral-rebound and probability-of-viral-remission using samples from two independent cohorts. These samples include a large number of post-treatment controllers, a rare population demonstrating sustained virologic suppression after ART-cessation. These signatures remain significant after adjusting for key demographic and clinical confounders. We also report mechanistic links between some of these biomarkers and HIV latency reactivation and/or myeloid inflammation in vitro. Finally, machine learning algorithms, based on selected sets of these biomarkers, predict time-to-viral-rebound with 74% capacity and probability-of-viral-remission with 97.5% capacity. In summary, we report non-invasive plasma biomarkers, with potential functional significance, that predict both the duration and probability of HIV remission after treatment interruption.

Time to Viral Rebound After Interruption of Modern Antiretroviral Therapies

BACKGROUND

Development of HIV remission strategies requires precise information on time to HIV rebound after treatment interruption, but there is uncertainty regarding whether modern ART regimens and timing of ART initiation may impact this outcome.

METHODS

ACTG A5345 enrolled individuals who initiated ART during chronic or early HIV infection and on suppressive ART for ≥2 years. Participants underwent carefully monitored antiretroviral interruption. ART was restarted upon two successive viral loads ≥1,000 copies/mL. We compared participants of A5345 with participants of 6 historic ACTG treatment interruption studies.

RESULTS

Thirty-three chronic-treated and 12 early-treated participants interrupted ART with evaluable time to viral rebound. Median time to viral rebound ≥1000 HIV RNA copies/mL was 22 days. Acute retroviral rebound syndrome was diagnosed in 9% of chronic-treated and none of early-treated individuals. All participants of the historic studies were on older protease inhibitor-based regimens while 97% of A5345 participants were on integrase inhibitor-based ART. There were no differences in the timing of viral rebound comparing A5345 versus historic studies. In a combined analysis, a higher percentage of early-treated participants remained off ART at post-treatment interruption week 12 (chronic vs early: 2% vs 9%, P=0.0496). One chronic-treated and one early-treated A5345 participant remained off ART for >24 weeks. All participants re-suppressed after ART re-initiation.

CONCLUSIONS

Early ART initiation, using either older or newer ART regimens, was associated with a significant delay in the time to HIV rebound after ART interruption, lowering the barrier for HIV remission.

Unified model of short- and long-term HIV viral rebound for clinical trial planning

Antiretroviral therapy (ART) effectively controls HIV infection, suppressing HIV viral loads. Typically suspension of therapy is rapidly followed by rebound of viral loads to high, pre-therapy levels. Indeed, a recent study showed that approximately 90% of treatment interruption study participants show viral rebound within at most a few months of therapy suspension, but the remaining 10%, showed viral rebound some months, or years, after ART suspension. Some may even never rebound. We investigate and compare branching process models aimed at gaining insight into these viral dynamics. Specifically, we provide a theory that explains both short- and long-term viral rebounds, and post-treatment control, via a multitype branching process with time-inhomogeneous rates, validated with data from Li et al. (Li et al. 2016 AIDS30, 343-353. (doi:10.1097/QAD.0000000000000953)). We discuss the associated biological interpretation and implications of our best-fit model. To test the effectiveness of an experimental intervention in delaying or preventing rebound, the standard practice is to suspend therapy and monitor the study participants for rebound. We close with a discussion of an important application of our modelling in the design of such clinical trials.

CCR5-edited CD4+ T cells augment HIV-specific immunity to enable post-rebound control of HIV replication

BackgroundWe conducted a phase I clinical trial that infused CCR5 gene-edited CD4+ T cells to determine how these T cells can better enable HIV cure strategies.MethodsThe aim of trial was to develop RNA-based approaches to deliver zinc finger nuclease (ZFN), evaluate the effect of CCR5 gene-edited CD4+ T cells on the HIV-specific T cell response, test the ability of infused CCR5 gene-edited T cells to delay viral rebound during analytical treatment interruption, and determine whether individuals heterozygous for CCR5 Δ32 preferentially benefit. We enrolled 14 individuals living with HIV whose viral load was well controlled by antiretroviral therapy (ART). We measured the time to viral rebound after ART withdrawal, the persistence of CCR5-edited CD4+ T cells, and whether infusion of 10 billion CCR5-edited CD4+ T cells augmented the HIV-specific immune response.ResultsInfusion of the CD4+ T cells was well tolerated, with no serious adverse events. We observed a modest delay in the time to viral rebound relative to historical controls; however, 3 of the 14 individuals, 2 of whom were heterozygous for CCR5 Δ32, showed post-viral rebound control of viremia, before ultimately losing control of viral replication. Interestingly, only these individuals had substantial restoration of HIV-specific CD8+ T cell responses. We observed immune escape for 1 of these reinvigorated responses at viral recrudescence, illustrating a direct link between viral control and enhanced CD8+ T cell responses.ConclusionThese findings demonstrate how CCR5 gene-edited CD4+ T cell infusion could aid HIV cure strategies by augmenting preexisting HIV-specific immune responses.REGISTRATIONClinicalTrials.gov NCT02388594.FundingNIH funding (R01AI104400, UM1AI126620, U19AI149680, T32AI007632) was provided by the National Institute of Allergy and Infectious Diseases (NIAID), the National Institute on Drug Abuse (NIDA), the National Institute of Mental Health (NIMH), and the National Institute of Neurological Disorders and Stroke (NINDS). Sangamo Therapeutics also provided funding for these studies.

Circulating CD30+CD4+ T Cells Increase Before Human Immunodeficiency Virus Rebound After Analytical Antiretroviral Treatment Interruption

BACKGROUND

Identification of nonviral markers of human immunodeficiency virus (HIV) infection that increase before viral rebound during analytical treatment interruption (ATI) may affect HIV persistence research. We previously showed that HIV ribonucleic acid (RNA) is enriched in CD30+CD4+ T cells in many individuals. Here, we studied CD30+CD4+ T-cell dynamics before ATI, during ATI (before detectable plasma RNA), and after HIV rebound.

METHODS

Peripheral blood mononuclear cells from 23 participants collected longitudinally from 5 Adult AIDS Clinical Trials Group studies incorporating ATI were included in this study. Flow cytometric characterization of expression of CD30 and markers of T-cell activation and exhaustion were performed along with HIV-1 RNA and deoxyribonucleic acid quantification and measurement of soluble plasma CD30 and CD30 ligand.

RESULTS

The percentage of CD4+ T cells expressing CD30 significantly increased from pre-ATI to postinterruption time points before detectible viremia (1.65 mean relative increase, P = .005). Seventy-seven percent of participants experienced an increase in CD30+ cells before viral rebound. In contrast, there were no significant differences between pre-ATI and postinterruption pre-rebound time points in percentages of lymphocytes expressing CD69, CD38/HLA-DR, or PD-1 until after HIV recrudescence.

CONCLUSIONS

CD30 may be a surrogate marker of early replication or viral transcriptional activity before detection by routine peripheral blood sampling.

No HIV-1 molecular evolution on long-term antiretroviral therapy initiated during primary HIV-1 infection

OBJECTIVE

Most studies about HIV-1 molecular evolution have shown the lack of viral evolution on effective antiretroviral therapy (ART), although controversial results have been documented. We therefore aimed to look for evidence of HIV-1 evolution in patients who initiated ART at the time of primary HIV-1 infection (PHI).

DESIGN

We included retrospectively 20 patients diagnosed at PHI, treated at the time of acute infection and with subsequent effective long-term suppressive ART (HIV viral load <20 copies/ml during at least 5 years without any blips).

METHODS

Longitudinal blood samples were deep sequenced using Illumina Miseq. Drug-resistance-associated mutations were retained at 2% cutoff and interpreted using the latest Agence Nationale de Recherches sur le Sida et les Hépatites Virales resistance algorithm. Viral evolution was established when temporal structure on maximum-likelihood phylogenetic tree and significant change over time of HIV-1 genetic diversity measured as the average pairwise distance was observed.

RESULTS

Emergences or disappearances of drug-resistance-associated mutations were detected in the blood cells during follow-up despite sustained virological control. In all patients, tree topologies showed an absence of segregation between sequences and blood viral populations from all time-points were intermingled. Comparison of the average pairwise distance showed the absence of significant viral diversity at the time of primary infection and afterwards during 5 years of full virological control under ART.

CONCLUSION

Despite a slight variation of minority resistance-associated mutation variants, there was no clear evidence of viral evolution during a prolonged period of time in this population of highly controlled adult patients treated at time of PHI.

Comparison of empirical and dynamic models for HIV viral load rebound after treatment interruption

OBJECTIVE

To compare empirical and mechanistic modeling approaches for describing HIV-1 RNA viral load trajectories after antiretroviral treatment interruption and for identifying factors that predict features of viral rebound process.

METHODS

We apply and compare two modeling approaches in analysis of data from 346 participants in six AIDS Clinical Trial Group studies. From each separate analysis, we identify predictors for viral set points and delay in rebound. Our empirical model postulates a parametric functional form whose parameters represent different features of the viral rebound process, such as rate of rise and viral load set point. The viral dynamics model augments standard HIV dynamics models-a class of mathematical models based on differential equations describing biological mechanisms-by including reactivation of latently infected cells and adaptive immune response. We use Monolix, which makes use of a Stochastic Approximation of the Expectation-Maximization algorithm, to fit non-linear mixed effects models incorporating observations that were below the assay limit of quantification.

RESULTS

Among the 346 participants, the median age at treatment interruption was 42. Ninety-three percent of participants were male and sixty-five percent, white non-Hispanic. Both models provided a reasonable fit to the data and can accommodate atypical viral load trajectories. The median set points obtained from two approaches were similar: 4.44 log10 copies/mL from the empirical model and 4.59 log10 copies/mL from the viral dynamics model. Both models revealed that higher nadir CD4 cell counts and ART initiation during acute/recent phase were associated with lower viral set points and identified receiving a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based pre-ATI regimen as a predictor for a delay in rebound.

CONCLUSION

Although based on different sets of assumptions, both models lead to similar conclusions regarding features of viral rebound process.

A flexible nonlinear mixed effects model for HIV viral load rebound after treatment interruption

Characterization of HIV viral rebound after the discontinuation of antiretroviral therapy is central to HIV cure research. We propose a parametric nonlinear mixed effects model for the viral rebound trajectory, which often has a rapid rise to a peak value followed by a decrease to a viral load set point. We choose a flexible functional form that captures the shapes of viral rebound trajectories and can also provide biological insights regarding the rebound process. Each parameter can incorporate a random effect to allow for variation in parameters across individuals. Key features of viral rebound trajectories such as viral set points are represented by the parameters in the model, which facilitates assessment of intervention effects and identification of important pretreatment interruption predictors for these features. We employ a stochastic expectation-maximization (StEM) algorithm to incorporate HIV-1 RNA values that are below the lower limit of assay quantification. We evaluate the performance of our model in simulation studies and apply the proposed model to longitudinal HIV-1 viral load data from five AIDS Clinical Trials Group treatment interruption studies.

Time to viral rebound and safety after antiretroviral treatment interruption in postpartum women compared with men

OBJECTIVE(S)

The short-term safety of treatment interruptions, a necessary part of cure studies, is not well established, particularly in women. We explored viral rebound kinetics and safety in a group of postpartum women discontinuing ART and compared results to men in historical interruption trials.

DESIGN

Prospective evaluation of time to virologic rebound.

METHODS

One thousand and seventy-six asymptomatic, virally suppressed, postpartum women living with HIV enrolled in the PROMISE trial with baseline CD4 cell counts at least 350 cells/μl underwent antiretroviral treatment (ART) discontinuation. Proportion with virologic suppression at weeks 4 and 12 were compared with participants in ACTG treatment interruption trials (91% male population).

RESULTS

In PROMISE, using interval censored methods, the estimated median time to HIV viral rebound was 2 weeks. An estimated 6% of women would remain virally suppressed at 30 weeks. Of those who had viral rebound by 30 weeks (N = 993), less than 4% experienced grade 3 or higher laboratory events, and 1% experienced WHO stage 2 or higher clinical events. Overall, less than 1% of participants progressed from WHO Stage 1 to Stage 2 or higher after discontinuation of ART, and 3.9% experienced a decline in CD4 cell count to less than 350 cells/μl or local treatment guidelines. A significantly higher proportion of women in PROMISE (25.4%) were virologically suppressed (<400 copies/ml) at 12 weeks compared with ACTG NWCS 371 participants (6.4%).

CONCLUSION

Temporary treatment interruptions in healthy, HIV-infected women with high CD4 cell counts can be well tolerated. Potential sex differences need to be considered in cure studies examining time to virologic rebound.

Virological Outcome Measures During Analytical Treatment Interruptions in Chronic HIV-1-Infected Patients

Background

Analytical treatment interruptions (ATIs) are essential in research on HIV cure. However, the heterogeneity of virological outcome measures used in different trials hinders the interpretation of the efficacy of different strategies.

Methods

We conducted a retrospective analysis of viral load (VL) evolution in 334 ATI episodes in chronic HIV-1-infected patients collected from 11 prospective studies. Quantitative (baseline VL, set point, delta set point, VL, and delta VL at given weeks after ATI, peak VL, delta peak VL, and area under the rebound curve) and temporal parameters (time to rebound [TtR], set point, peak, and certain absolute and relative VL thresholds) were described. Pairwise correlations between parameters were analyzed, and potential confounding factors (sex, age, time of known HIV infection, time on ART, and immunological interventions) were evaluated.

Results

The set point was lower than baseline VL (median delta set point, –0.26; P < .001). This difference was >1 log10 copies/mL in 13.9% of the cases. The median TtR was 2 weeks; no patients had an undetectable VL at week 12. The median time to set point was 8 weeks: by week 12, 97.4% of the patients had reached the set point. TtR and baseline VL were correlated with most temporal and quantitative parameters. The variables independently associated with TtR were baseline VL and the use of immunological interventions.

Conclusions

TtR could be an optimal surrogate marker of response in HIV cure strategies. Our results underline the importance of taking into account baseline VL and other confounding factors in the design and interpretation of these studies.

Learning From the Exceptions: HIV Remission in Post-treatment Controllers

Among the top priorities of the HIV field is the search for therapeutic interventions that can lead to sustained antiretroviral therapy (ART)-free HIV remission. Although the majority of HIV-infected persons will experience rapid viral rebound after ART interruption, there are rare individuals, termed post-treatment controllers (PTCs), who demonstrate sustained virologic suppression for months or years after treatment cessation. These individuals are considered an ideal example of durable HIV control, with direct implications for HIV cure research. However, understanding of the mechanisms behind the capacity of PTCs to control HIV remains incomplete. This is in part due to the scarcity of PTCs identified through any one research center or clinical trial, and in part because of the limited scope of studies that have been performed in these remarkable individuals. In this review, we summarize the results of both clinical and basic research studies of PTCs to date, explore key differences between PTCs and HIV spontaneous controllers, examine potential mechanisms of post-treatment control, and discuss unanswered questions and future research directions in this field.

Predictions of time to HIV viral rebound following ART suspension that incorporate personal biomarkers

Antiretroviral therapy (ART) effectively controls HIV infection, suppressing HIV viral loads. Suspension of therapy is followed by rebound of viral loads to high, pre-therapy levels. However, there is significant heterogeneity in speed of rebound, with some rebounds occurring within days, weeks, or sometimes years. We present a stochastic mathematical model to gain insight into these post-treatment dynamics, specifically characterizing the dynamics of short term viral rebounds (≤ 60 days). Li et al. (2016) report that the size of the expressed HIV reservoir, i.e., cell-associated HIV RNA levels, and drug regimen correlate with the time between ART suspension and viral rebound to detectable levels. We incorporate this information and viral rebound times to parametrize our model. We then investigate insights offered by our model into the underlying dynamics of the latent reservoir. In particular, we refine previous estimates of viral recrudescence after ART interruption by accounting for heterogeneity in infection rebound dynamics, and determine a recrudescence rate of once every 2-4 days. Our parametrized model can be used to aid in design of clinical trials to study viral dynamics following analytic treatment interruption. We show how to derive informative personalized testing frequencies from our model and offer a proof-of-concept example. Our results represent first steps towards a model that can make predictions on a person living with HIV (PLWH)'s rebound time distribution based on biomarkers, and help identify PLWH with long viral rebound delays.

Characterization of Intact Proviruses in Blood and Lymph Node from HIV-Infected Individuals Undergoing Analytical Treatment Interruption

The role of lymphoid tissue as a potential source of HIV-1 rebound following interruption of antiretroviral therapy (ART) is uncertain. To address this issue, we compared the latent viruses obtained from CD4+ T cells in peripheral blood and lymph nodes to viruses emerging during treatment interruption. Latent viruses were characterized by sequencing near-full-length (NFL) proviral DNA and env from viral outgrowth assays (VOAs). Five HIV-1-infected individuals on ART were studied, four of whom participated in a clinical trial of a TLR9 agonist that included an analytical treatment interruption. We found that 98% of intact or replication-competent clonal sequences overlapped between blood and lymph node. In contrast, there was no overlap between 205 latent reservoir and 125 rebound sequences in the four individuals who underwent treatment interruption. However, rebound viruses could be accounted for by recombination. The data suggest that CD4+ T cells carrying latent viruses circulate between blood and lymphoid tissues in individuals on ART and support the idea that recombination may play a role in the emergence of rebound viremia.IMPORTANCE HIV-1 persists as a latent infection in CD4+ T cells that can be found in lymphoid tissues in infected individuals during ART. However, the importance of this tissue reservoir and its contribution to viral rebound upon ART interruption are not clear. In this study, we sought to compare latent HIV-1 from blood and lymph node CD4+ T cells from five HIV-1-infected individuals. Further, we analyzed the contribution of lymph node viruses to viral rebound. We observed that the frequencies of intact proviruses were the same in blood and lymph node. Moreover, expanded clones of T cells bearing identical proviruses were found in blood and lymph node. These latent reservoir sequences did not appear to be the direct origin of rebound virus. Instead, latent proviruses were found to contribute to the rebound compartment by recombination.

Clinical trials of antiretroviral treatment interruption in HIV-infected individuals

: Despite the benefits of antiretroviral therapy (ART) for people living with HIV, there has been a long-standing research interest in interrupting ART as a strategy to minimize adverse effects of ART as well as to test interventions aiming to achieve a degree of virological control without ART. We performed a systematic review of HIV clinical studies involving treatment interruption from 2000 to 2017 to describe the differences between treatment interruption in studies that contained and didn't contain an intervention. We assessed differences in monitoring strategies, threshold to restart ART, duration and adverse outcomes of treatment interruption, and factors aimed at minimizing transmission. We found that treatment interruption has been incorporated into 159 clinical studies since 2000 and is increasingly being included in trials to assess the efficacy of interventions to achieve sustained virological remission off ART. Great heterogeneity was noted in immunological, virological and clinical monitoring strategies, as well as in thresholds to recommence ART. Treatment interruption in recent intervention studies were more closely monitored, had more conservative thresholds to restart ART and had a shorter treatment interruption duration, compared with older treatment interruption studies that didn't include an intervention.

The Control of HIV After Antiretroviral Medication Pause (CHAMP) Study: Posttreatment Controllers Identified From 14 Clinical Studies

Background

HIV posttreatment controllers are rare individuals who start antiretroviral therapy (ART), but maintain HIV suppression after treatment interruption. The frequency of posttreatment control and posttreatment interruption viral dynamics have not been well characterized.

Methods

Posttreatment controllers were identified from 14 studies and defined as individuals who underwent treatment interruption with viral loads ≤400 copies/mL at two-thirds or more of time points for ≥24 weeks. Viral load and CD4+ cell dynamics were compared between posttreatment controllers and noncontrollers.

Results

Of the 67 posttreatment controllers identified, 38 initiated ART during early HIV infection. Posttreatment controllers were more frequently identified in those treated during early versus chronic infection (13% vs 4%, P < .001). In posttreatment controllers with weekly viral load monitoring, 45% had a peak posttreatment interruption viral load of ≥1000 copies/mL and 33% had a peak viral load ≥10000 copies/mL. Of posttreatment controllers, 55% maintained HIV control for 2 years, with approximately 20% maintaining control for ≥5 years.

Conclusions

Posttreatment control was more commonly identified amongst early treated individuals, frequently characterized by early transient viral rebound and heterogeneous durability of HIV remission. These results may provide mechanistic insights and have implications for the design of trials aimed at achieving HIV remission.

HIV-1 proviral landscapes distinguish posttreatment controllers from noncontrollers

HIV posttreatment controllers (PTCs) represent a natural model of sustained HIV remission, but they are rare and little is known about their viral reservoir. We obtained 1,450 proviral sequences after near-full-length amplification for 10 PTCs and 16 posttreatment noncontrollers (NCs). Before treatment interruption, the median intact and total reservoir size in PTCs was 7-fold lower than in NCs, but the proportion of intact, defective, and total clonally expanded proviral genomes was not significantly different between the 2 groups. Quantification of total but not intact proviral genome copies predicted sustained HIV remission as 81% of NCs, but none of the PTCs had a total proviral genome greater than 4 copies per million peripheral blood mononuclear cells (PBMCs). The results highlight the restricted intact and defective HIV reservoir in PTCs and suggest that total proviral genome burden could act as the first biomarker for identifying PTCs. Total and defective but not intact proviral copy numbers correlated with levels of cell-associated HIV RNA, activated NK cell percentages, and both HIV-specific CD4+ and CD8+ responses. These results support the concept that defective HIV genomes can lead to viral antigen production and interact with both the innate and adaptive immune systems.

Effect of Short-Term Antiretroviral Therapy Interruption on Levels of Integrated HIV DNA

Analytic treatment interruption (ATI) studies are required to evaluate strategies aimed at achieving ART-free HIV remission, but the impact of ATI on the viral reservoir remains unclear. We validated a DNA size selection-based assay for measuring levels of integrated HIV DNA and applied it to assess the effects of short-term ATI on the HIV reservoir. Samples from participants from four AIDS Clinical Trials Group ATI studies were assayed for integrated HIV DNA levels. Cryopreserved peripheral blood mononuclear cells (PBMCs) were obtained for 12 participants with available samples pre-ATI and approximately 6 months after ART resumption. Four participants also had samples available during the ATI. The median duration of ATI was 12 weeks. Validation of the HIV integrated DNA size-exclusion (HIDE) assay was performed using samples spiked with unintegrated HIV DNA, HIV-infected cell lines, and participant PBMCs. The HIDE assay eliminated 99% of unintegrated HIV DNA species and strongly correlated with the established Alu-gag assay. For the majority of individuals, integrated DNA levels increased during ATI and subsequently declined upon ART resumption. There was no significant difference in the levels of integrated HIV DNA between the pre- and post-ATI time points, with a median ratio of post- to pre-ATI HIV DNA levels of 0.95. Using a new integrated HIV DNA assay, we found minimal change in the levels of integrated HIV DNA in participants who underwent an ATI, followed by 6 months of ART. This suggests that short-term ATI can be conducted without a significant impact on the levels of integrated proviral DNA in the peripheral blood.IMPORTANCE Interventions aimed at achieving sustained antiretroviral therapy (ART)-free HIV remission require treatment interruption trials to assess their efficacy. However, these trials are accompanied by safety concerns related to the expansion of the viral reservoir. We validated an assay that uses an automated DNA size-selection platform for quantifying levels of integrated HIV DNA and is less sample- and labor-intensive than current assays. Using stored samples from AIDS Clinical Trials Group studies, we found that short-term ART discontinuation had minimal impact on integrated HIV DNA levels after ART resumption, providing reassurance about the reservoir effects of short-term treatment interruption trials.

Elevated Level of CD4+ T Cell Immune Activation in Acutely HIV-1-Infected Stage Associates With Increased IL-2 Production and Cycling Expression, and Subsequent CD4+ T Cell Preservation

Persistent immune activation is a striking consequence of HIV-1 infection and a driving force of CD4⁺ T cell depletion and AIDS events during chronic infection. High level of T cell immune activation associates with antiretroviral therapy (ART)-treated clinical outcomes in chronically HIV-1-infected patients. However, the role of T cell activation during acute infection stage in subsequent CD4⁺ T cell decline in the absence of ART treatment is unknown. In this study, we enrolled 26 acutely HIV-1-infected patients in the absence of ART treatment from a prospective acute HIV-1 infection cohort in Beijing (PRIMO). A comprehensive analysis of CD4⁺ and CD8⁺ T cell immune activation during acute infection stage and the clinical outcomes was studied. We found that patients with higher level of CD4⁺ T cell activation (%CD38⁺HLA-DR⁺CD4⁺ T cells) exhibited more effective function (%IL-2 production and %ki67 expression) in CD4⁺ T cells compared to those from patients without increased T cell activation at the acute phase. Direct correlations were observed between CD4⁺ T cell activation and the percentages of IL-2-producing or ki67-expressing CD4⁺ T cells in patients at the acute phase of infection. Importantly, the increased levels of CD4⁺ T cell immune activation, IL-2 production, and cycling expression during acute infection were associated with less decline of CD4⁺ T cell after 2 years of infection. However, immune exhaustion molecules in acute infection, including CD160, T cell immunoglobulin and ITIM domain, programmed cell death protein 1, and T cell immunoglobulin and mucin 3, were not associated with the CD4⁺ T cell depletion. These significant associations of CD4⁺ T cell activation were not demonstrable for CD8⁺ T cell activation at the acute phase. Taken together, our observations provide new insight into the possible role of T cell activation in preventing CD4⁺ T cell depletion during acute HIV-1 infection.

"We Need to Deploy Them Very Thoughtfully and Carefully": Perceptions of Analytical Treatment Interruptions in HIV Cure Research in the United States-A Qualitative Inquiry

Strategies to control HIV in the absence of antiretroviral therapy are needed to cure HIV. However, such strategies will require analytical treatment interruptions (ATIs) to determine their efficacy. We investigated how U.S. stakeholders involved in HIV cure research perceive ATIs. We conducted 36 in-depth interviews with three groups of stakeholders: 12 people living with HIV, 11 clinician-researchers, and 13 policy-makers/bioethicists. Qualitative data revealed several themes. First, there was little consensus on when ATIs would be ethically warranted. Second, the most frequent perceived hypothetical motivators for participating in research on ATIs were advancing science and contributing to society. Third, risks related to viral rebound were the most prevalent concerns related to ATIs. Stakeholders suggested ways to minimize the risks of ATIs in HIV cure research. Increased cooperation between scientists and local communities may be useful for minimizing risk. Further ethics research is necessary.

Brief Report: Relationship Among Viral Load Outcomes in HIV Treatment Interruption Trials

Viral load (VL) rebound timing and set point were analyzed in 235 participants undergoing analytic treatment interruption (ATI) in 6 AIDS Clinical Trials Group studies. There was no significant association between rebound timing and ATI VL set point for those who rebounded ≤12 weeks. VL set points were lower in participants with rebound >12 weeks (P < 0.001) and participants treated during early infection (P < 0.001). Pre-antiretroviral therapy VL correlated with set point, though 68% of participants had a set point lower than pre-antiretroviral therapy VL. These results illustrate complex relationships between post-ATI virologic outcomes and the potential presence of biological factors mediating rebound timing and set point.

Post-treatment control or treated controllers? Viral remission in treated and untreated primary HIV infection

Supplemental Digital Content is available in the text

Objective(s):

An HIV cure will impose aviraemia that is sustained following the withdrawal of antiretroviral therapy (ART). Understanding the efficacy of novel interventions aimed at curing HIV requires characterization of both natural viral control and the effect of ART on viral control after treatment interruption.

Design:

Analysis of transient viral control in recent seroconverters in the Short Pulse AntiRetroviral Therapy at Acute Seroconversion trial.

Methods:

We compared untreated and treated HIV seroconverters (n = 292) and identified periods of control (plasma HIV RNA < 400 copies/ml for ≥16 weeks off therapy) in 7.9% of ART-naive participants, and in 12.0% overall. HIV DNA was measured by qPCR, and HIV-specific CD8⁺ responses were measured by enzyme-linked immunosorbent spot assay (ELISpot). T-cell activation and exhaustion were measured by flow cytometry.

Results:

At baseline, future controllers had lower HIV DNA, lower plasma HIV RNA, higher CD4⁺ : CD8⁺ ratios (all P < 0.001) and higher CD4⁺ cell counts (P < 0.05) than noncontrollers. Among controllers, the only difference between the untreated and those who received ART was higher baseline HIV RNA in the latter (P = 0.003), supporting an added ART effect.

Conclusion:

Consideration of spontaneous remission in untreated individuals will be critical to avoid overestimating the effect size of new interventions used in HIV cure studies.

HIV-1 antibody 3BNC117 suppresses viral rebound in humans during treatment interruption

Interruption of combination antiretroviral therapy in HIV-1-infected individuals leads to rapid viral rebound. Here we report the results of a phase IIa open label clinical trial evaluating 3BNC117,a broad and potent neutralizing antibody against the CD4 binding site of the HIV-1 Env protein, during analytical treatment interruption in 13 HIV-1-infected individuals. Participants with 3BNC117-sensitive virus outgrowth cultures were enrolled. Results show that two or four 30 mg kg(-1) 3BNC117 infusions,separated by 3 or 2 weeks, respectively, are generally well tolerated.Infusions are associated with a delay in viral rebound of 5-9 weeks after two infusions, and up to 19 weeks after four infusions, or an average of 6.7 and 9.9 weeks, respectively, compared with 2.6 weeks for historical controls (P < 0.00001). Rebound viruses arise predominantly from a single provirus. In most individuals,emerging viruses show increased resistance, indicating escape.However, 30% of participants remained suppressed until antibody concentrations waned below 20 μg ml(-1), and the viruses emerging in all but one of these individuals showed no apparent resistance to 3BCN117, suggesting failure to escape over a period of 9-19 weeks.We conclude that the administration of 3BNC117 exerts strong selective pressure on HIV-1 emerging from latent reservoirs during analytical treatment interruption in humans.

Synergies, tensions and challenges in HIV prevention, treatment and cure research: exploratory conversations with HIV experts in South Africa

Background

The ethical concerns associated with HIV prevention and treatment research have been widely explored in South Africa over the past 3 decades. However, HIV cure research is relatively new to the region and significant ethical and social challenges are anticipated. There has been no published empirical enquiry in Africa into key informant perspectives on HIV cure research. Consequently, this study was conducted to gain preliminary data from South African HIV clinicians, researchers and activists.

Methods

In-depth interviews were conducted on a purposive sample of fourteen key informants in South Africa. Audiotaped interviews were transcribed verbatim with concurrent thematic analysis. The perspectives of HIV clinicians, researchers and activists were captured. Analyst triangulation occurred as the data were analysed by three authors independently.

Results

The rapid evolution of HIV cure research agendas was prominent with participants expressing some concern that the global North was driving the cure agenda. Participants described a symbiotic relationship between cure, treatment and prevention research necessitating collaboration. Assessing and managing knowledge and expectations around HIV cure research emerged as a central theme related to challenges to constructing ‘cure’ - how patients understand the idea of cure is important in explaining the complexity of cure research especially in the South African context where understanding of science is often challenging. Managing expectations and avoiding curative misconception will have implications for consent processes. Unique strategies in cure research could include treatment interruption, which has the potential to create therapeutic and ethical conflict and will be perceived as a significant risk. Ethical challenges in cure research will impact on informed consent and community engagement.

Conclusions

It was encouraging to note the desire for synergy amongst researchers and clinicians working in the fields of prevention, treatment and cure. Translation of complex HIV cure science into lay language is critical. Moving forward, RECs must be adequately constituted with scientific expertise and community representation when reviewing cure protocols. It is hoped that knowledge and resource sharing in the context of collaboration between research scientists working in cure and those working in treatment and prevention will accelerate progress towards cure.

The size of the expressed HIV reservoir predicts timing of viral rebound after treatment interruption

OBJECTIVES

Therapies to achieve sustained antiretroviral therapy-free HIV remission will require validation in analytic treatment interruption (ATI) trials. Identifying biomarkers that predict time to viral rebound could accelerate the development of such therapeutics.

DESIGN

A pooled analysis of participants from six AIDS Clinical Trials Group ATI studies to identify predictors of viral rebound.

METHODS

Cell-associated DNA (CA-DNA) and CA-RNA were quantified in pre-ATI peripheral blood mononuclear cell samples, and residual plasma viremia was measured using the single-copy assay.

RESULTS

Participants who initiated antiretroviral therapy (ART) during acute/early HIV infection and those on a non-nucleoside reverse transcriptase inhibitor-containing regimen had significantly delayed viral rebound. Participants who initiated ART during acute/early infection had lower levels of pre-ATI CA-RNA (acute/early vs. chronic-treated: median <92 vs. 156 HIV-1 RNA copies/10 CD4 cells, P < 0.01). Higher pre-ATI CA-RNA levels were significantly associated with shorter time to viral rebound (≤4 vs. 5-8 vs. >8 weeks: median 182 vs. 107 vs. <92 HIV-1 RNA copies/10 CD4 cells, Kruskal-Wallis P < 0.01). The proportion of participants with detectable plasma residual viremia prior to ATI was significantly higher among those with shorter time to viral rebound.

CONCLUSION

Higher levels of HIV expression while on ART are associated with shorter time to HIV rebound after treatment interruption. Quantification of the active HIV reservoir may provide a biomarker of efficacy for therapies that aim to achieve ART-free HIV remission.

Advancing the HIV cure agenda: the next 5 years

PURPOSE OF REVIEW

To explore how ethical considerations, improved diagnostics and data from clinical trials might see the lowering of some of the barriers blocking a cure for HIV infection over the next 5 years.

RECENT FINDINGS

Despite the recent well publicized but eventually disappointing case reports, there remains only one successful HIV cure, the 'Berlin patient'. We will review the data suggesting that more potent agents might achieve in-vivo viral activation and explore the tantalizing phenomenon of 'posttreatment control' following treatment in primary HIV infection. We will also explore how new assays and novel interventions might move the field forward.

SUMMARY

There is a need for new agents that can be safely tested to impact the viral reservoir, a more meaningful understanding of how to assay patient samples, and research into mechanisms behind how the reservoir is established and impacted by therapy. With HIV+ve individuals responding so well to antiretroviral therapy, new trials must be tested hand-in-hand with guidance from patient representatives, especially with respect to determining the acceptable risk. The road to a cure is going to be difficult, but it is vital that inevitable disappointments do not detract from the final goal, which remains worth striving for.

Barriers to antiretroviral therapy adherence and plasma HIV RNA suppression among AIDS clinical trials group study participants

We conducted a secondary data analysis of 11 AIDS Clinical Trials Group (ACTG) studies to examine longitudinal associations between 14 self-reported antiretroviral therapy (ART) adherence barriers (at 12 weeks) and plasma HIV RNA (at 24 weeks) and to discern the relative importance of these barriers in explaining virologic detectability. Studies enrolled from 1997 to 2003 and concluded between 2002 and 2012. We included 1496 (54.2% of the original sample) with complete data. The most commonly selected barriers were "away from home" (21.9%), "simply forgot" (19.6%), "change in daily routine" (19.5%), and "fell asleep/slept through dosing time" (18.9%). In bivariate analyses, "too many pills to take" (OR=0.43, p<0.001), "wanted to avoid side effects" (OR=0.54, p=0.001), "felt drug was toxic/harmful" (OR=0.44, p<0.001), "felt sick or ill" (OR=0.49, p<0.001), "felt depressed/overwhelmed" (OR=0.58, p=0.004), and "problem taking pills at specified time" (OR=0.71, p=0.04) were associated with a lower odds of an undetectable HIV RNA. "Too many pills to take," "wanted to avoid side effects," "felt drug was toxic/harmful," "felt sick/ill,", and "felt depressed/overwhelmed" had the highest relative importance in explaining virologic detectability. "Simply forgot" was not associated with HIV RNA (OR=0.99, p=0.95) and was ninth in its relative importance. Adherence interventions should prioritize barriers with highest importance in explaining virologic outcomes rather than focusing on more commonly reported barriers.

HIV reservoir dynamics in the face of highly active antiretroviral therapy

Upon discontinuation of highly active antiretroviral therapy (HAART), human immunodeficiency virus (HIV)-infected individuals experience a brisk rebound in blood plasma viremia due to the exodus of HIV from various body reservoirs. Assessment of HIV dynamics during HAART and following treatment discontinuation is essential to better understand HIV persistence. Here we will first provide a brief overview of the molecular mechanisms involved in HIV reservoir formation and persistence. After a summary of HAART-mediated HIV decay within peripheral blood, we discuss findings from clinical studies examining the effects of HAART initiation and interruption on HIV reservoir dynamics in major anatomical compartments, including lymph nodes and spleen, gut associated lymphoid tissue, reproductive organs, the central nervous system, and the lungs. Features contributing to these reservoirs as distinct compartments, including anatomical features, the presence of drug transporters, and the effect of co-infection, are also discussed.

Short communication: Longitudinal changes in peripheral blood NK cells during the first year of HIV-1 Infection in CD4Low and CD4High patient groups

Natural killer (NK) cells may modulate the pathogenesis of primary HIV-1 infection. However, the relationship between the number and function of NK cells during an acute HIV-1 infection and HIV-1 disease progression remains to be elucidated. In this study, we enrolled two distinct patient groups. One group progressed to where their CD4 cell counts fell below 200 cells/μl within 2 years (CD4Low group), while the CD4 cell counts of the other group remained above 500 cells/μl for over 2 years (CD4High group). We compared the number and function of NK cells during the first year of HIV-1 infection between the two distinct groups. We found that the number of total NK cells and the number of cells in the CD56(dim)CD16(pos) subset rapidly decreased in both groups during early HIV-1 infection. The absolute number of total NK cells and CD56(dim)CD16(pos) NK cells was significantly higher in the CD4High group when compared to the CD4Low group during the first month of infection. No significant difference between the numbers of CD56(bright)CD16(neg) NK cells of the two groups was observed. However, more CD56(neg)CD16(pos) NK cells were found in the CD4Low group than in the CD4High group. We also found that NK cell function increased within the first 3 months of HIV-1 infection in the CD4High group and then exhibited a decreasing trend. However, in the CD4Low group, NK cell function did not increase significantly within the first 3 months of HIV-1 infection but then gradually increased. We concluded, therefore, that robust NK functioning cells that are present during an acute HIV-1 infection might be beneficial in controlling HIV-1 disease progression.

Update on antiretroviral treatment during primary HIV infection

Primary HIV-1 infection covers a period of around 12 weeks in which the virus disseminates from the initial site of infection into different tissues and organs. In this phase, viremia is very high and transmission of HIV is an important issue. Most guidelines recommend antiretroviral treatment in patients who are symptomatic, although the indication for treatment remains inconclusive in asymptomatic patients. In this article the authors review the main virological and immunological events during this early phase of infection, and discuss the arguments for and against antiretroviral treatment. Recommendations of different guidelines, the issue of the HIV transmission and transmission of resistance to antiretroviral drugs, as well as recently available information opening perspectives for functional cure in patients treated in very early steps of HIV infection are also discussed.

HIV cure research: advances and prospects

Thirty years after the identification of HIV, a cure for HIV infection is still to be achieved. Advances of combined antiretroviral therapy (cART) in recent years have transformed HIV infection into a chronic disease when treatment is available. However, in spite of the favorable outcomes provided by the newer therapies, cART is not curative and patients are at risk of developing HIV-associated disorders. Moreover, universal access to antiretroviral treatment is restricted by financial obstacles. This review discusses the most recent strategies that have been developed in the search for an HIV cure and to improve life quality of people living with HIV.

Immunological and virological benefits resulted from short-course treatment during primary HIV infection: a meta-analysis

OBJECTIVES

To assess the potential immunological and virological effects that result from short-course antiretroviral treatment during primary HIV infection (PHI). And to investigate whether treatment initiation time, treatment duration and follow-up time after treatment interruption would affect these post-treatment immunovirological outcomes.

METHODS

We systematically searched PubMed, Cochrane Library (to September 2013) and retrieved conference abstracts for studies regarding effects of early treatment during PHI on CD4 count and viral load (VL). Using the method of calculating weighted mean differences with Stata11.0, we conducted meta-analyses on the effect of early treatment on CD4 count and VL. Then we performed subgroup analyses by follow-up time after treatment interruption, treatment initiation time and treatment duration. Baseline immunovirological characteristics were also analyzed to account for potential bias.

RESULTS

Compared to the untreated arm, treatment during PHI not only increased CD4 count by 85.92 cells/μl but also lowered viral load by 0.30 log copies/ml within one year after treatment interruption. However, the benefits declined gradually, reaching no significance 12-24 months after treatment interruption. Baseline immunovirological characteristics and sensitivity analyses of randomized controlled trials indicated that the benefits mentioned above were underestimated. Extending treatment duration beyond 12 months did not increase efficacy.

CONCLUSIONS

Short-course treatment during PHI was associated with immunological and virological benefits which last for at least one year after treatment interruption. The conclusions from our study would help the decision-making in the clinical management of PHI.

A cure for AIDS: a matter of timing?

Despite the huge clinical success of antiretroviral therapy, several factors such as side effects, requirement of life-long adherence, high cost, incomplete access to therapies and development of drug resistance make the quest for an ultimate cure of HIV/AIDS a worldwide priority of biomedical research. In this respect, several sterilizing or functional cures have been reported in the last years in both non-human primates and humans. This review provides a summary of the main results achieved so far, outlining their strengths as well as their limitations. A synthetic interpretation of these results could be pivotal in order to develop an effective and widely available cure.

Antiretroviral therapy initiated during acute HIV infection fails to prevent persistent T-cell activation

Initiation of antiretroviral therapy during acute HIV-1 infection may prevent persistent immune activation. We analyzed longitudinal CD38+HLA-DR+ CD8+ T-cell percentages in 31 acutely infected individuals who started early (median 43 days since infection) and successful antiretroviral therapy, and maintained viral suppression through 96 weeks. Pretherapy a median of 72.6% CD8+ T cells were CD38+HLA-DR+, and although this decreased to 15.6% by 96 weeks, it remained substantially higher than seronegative controls (median 8.9%, P = 0.008). Shorter time to suppression predicted lower activation at 96 weeks. These results support the hypothesis that very early events in HIV-1 pathogenesis may result in prolonged immune dysfunction.

The detection and management of early HIV infection: a clinical and public health emergency

This review considers the detection and management of early HIV infection (EHI), defined here as the first 6 months of infection. This phase is clinically important because a reservoir of infected cells formed in the individual renders HIV incurable, and the magnitude of viremia at the end of this period predicts the natural history of disease. Epidemiologically, it is critical because the very high viral load that typically accompanies early infection also makes infected individuals maximally contagious to their sexual partners. Future efforts to prevent HIV transmission with expanded testing and treatment may be compromised by elevated transmission risk earlier in the course of HIV infection, although the extent of this impact is yet unknown. Treatment as prevention efforts will nevertheless need to develop strategies to address testing, linkage to care, and treatment of EHI. Cost-effective and efficient identification of more persons with early HIV will depend on advancements in diagnostic technology and strengthened symptom-based screening strategies. Treatment for persons with EHI must balance individual health benefits and reduction of the risk of onward viral transmission. An increasing body of evidence supports the use of immediate antiretroviral therapy to treat EHI to maintain CD4 count and functionality, limit the size of the HIV reservoir, and reduce the risk of onward viral transmission. Although we can anticipate considerable challenges in identifying and linking to care persons in the earliest phases of HIV infection, there are many reasons to pursue this strategy.

Acute HIV-1 infection in the Southeastern United States: a cohort study

In 1998 a collaboration between Duke University and the University of North Carolina, Chapel Hill (UNC) was founded to enhance identification of persons with acute HIV-1 infection (AHI). The Duke-UNC AHI Research Consortium Cohort consists of patients ≥18 years old with a positive nucleic acid amplification test (NAAT) and either a negative enzyme immunoassay (EIA) test or a positive EIA with a negative/indeterminate Western blot. Patients were referred to the cohort from acute care settings and state-funded HIV testing sites that use NAAT testing on pooled HIV-1 antibody-negative samples. Between 1998 and 2010, 155 patients with AHI were enrolled: 81 (52%) African-Americans, 63 (41%) white, non-Hispanics, 137 (88%) males, 108 (70%) men who have sex with men (MSM), and 18 (12%) females. The median age was 27 years (IQR 22-38). Most (n=138/155) reported symptoms with a median duration of 17.5 days. The median nadir CD4 count was 408 cells/mm(3) (IQR 289-563); the median observed peak HIV-1 level was 726,859 copies/ml (IQR 167,585-3,565,728). The emergency department was the most frequent site of initial presentation (n=55/152; 3 missing data). AHI diagnosis was made at time of first contact in 62/137 (45%; 18 missing data) patients. This prospectively enrolled cohort is the largest group of patients with AHI reported from the Southeastern United States. The demographics reflect the epidemic of this geographic area with a high proportion of African-Americans, including young black MSM. Highlighting the challenges of diagnosing AHI, less than half of the patients were diagnosed at the first healthcare visit. Women made up a small proportion despite increasing numbers in our clinics.

Continuous versus intermittent treatment strategies during primary HIV-1 infection: the randomized ANRS INTERPRIM Trial

OBJECTIVES

The ANRS-112 INTERPRIM trial assessed whether fixed-cycles of antiretroviral treatment interruption (ART-STI) combined or not with pegylated interferon alpha-2b (peg-IFN) could lower viral load and achieve a healthier immune system in patients diagnosed during primary HIV-1-infection (PHI).

DESIGN AND METHODS

Patients were randomized to receive either continuous ART (cART) during 72 weeks, or cART during 36 weeks followed by three ART-STIs, or the same ART-STIs associated with peg-IFN during the first 14 weeks and each interruption (ART-STI-IFN). Treatment was stopped at week 72. Final evaluation was based on plasma HIV-RNA level 6 months after the last treatment interruption.

RESULTS

Eighty-seven percent of patients achieved undetectable HIV-RNA at week 32, with no deleterious impact of sequential treatment interruptions (STIs). Viral rebounds during interruptions were lower in the ART-STI-IFN than in the ART-STI group and during the second and third interruptions compared with the first one. However, HIV-RNA levels, CD4 T-cell counts and CD4 T/CD8 T ratios were similar between groups after the 6-month interruption, with a persistent effect on CD4 T cells and total cell-associated HIV-DNA levels. Predictive factors of virological outcome were HIV-RNA and HIV-DNA levels at PHI and HIV-DNA levels at treatment interruption. HIV-specific responses did not differ between strategies and were not associated with outcome. Forty-eight percent of patients experienced treatment resumption during long-term follow-up without difference between groups.

CONCLUSION

When initiated during PHI, STIs associated or not with IFN did not result in a different outcome as compared to cART. All regimens showed a high response rate and a sustained immunological benefit after cessation.

Antiretroviral therapy in Indian setting: when & what to start with, when & what to switch to?

With the rapid scale up of antiretroviral therapy, there is a dramatic decline in HIV related morbidity and mortality in both developed and developing countries. Several new safe antiretroviral, and newer class of drugs and monitoring assays are developed recently. As a result the treatment guideline for the management of HIV disease continue to change. This review focuses on evolving science on Indian policy - antiretroviral therapy initiation, which drugs to start with, when to change the initial regimen and what to change.