The RIO trial: rationale, design, and the role of community involvement in a randomised placebo-controlled trial of antiretroviral therapy plus dual long-acting HIV-specific broadly neutralising antibodies (bNAbs) in participants diagnosed with recent HIV infection-study protocol for a two-stage randomised phase II trial

Early Viral Dynamics Predict Human Immunodeficiency Virus Posttreatment Control After Analytic Treatment Interruption

BACKGROUND

A key research priority for developing a human immunodeficiency virus (HIV) cure strategy is to define the viral dynamics and biomarkers associated with sustained posttreatment control. The ability to predict the likelihood of sustained posttreatment control or noncontrol could minimize the time off antiretroviral therapy (ART) for those destined to be controllers and anticipate longer periods off ART for those destined to be controllers.

METHODS

Mathematical modeling and machine learning were used to characterize virologic predictors of long-term virologic control, using viral kinetics data from several studies in which participants interrupted ART. Predictors of post-ART outcomes were characterized using data accumulated from the time of treatment interruption, replicating real-time data collection in a clinical study, and classifying outcomes as either posttreatment control (plasma viremia, ≤400 copies/mL at 2 of 3 time points for ≥24 weeks) or noncontrol.

RESULTS

Potential predictors of virologic control were the time to rebound, the rate of initial rebound, and the peak plasma viremia. We found that people destined to be noncontrollers could be identified within 3 weeks of rebound (prediction scores: accuracy, 80%; sensitivity, 82%; specificity, 71%).

CONCLUSIONS

Given the widespread use of analytic treatment interruption in cure-related trials, these predictors may be useful to increase the safety of analytic treatment interruption through early identification of people who are unlikely to become posttreatment controllers.

Time to HIV viral rebound and frequency of post-treatment control after analytical interruption of antiretroviral therapy: an individual data-based meta-analysis of 24 prospective studies

The only current strategy to test efficacy of novel interventions for sustained HIV control without antiretroviral therapy (ART) among people with HIV (PWH) is through an analytical treatment interruption (ATI). Inclusion of 'placebo' controls in ATIs poses ethical, logistical, and economic challenges. To understand viral dynamics and rates of post-treatment control (PTC) after ATI among PWH receiving either placebo or no intervention, we undertook an individual-participant data meta-analysis. In total, 24 eligible prospective studies with 382 individuals with ≥5 plasma HIV RNA viral loads (pVLs) within the first 84 days post-ATI were included. Early-ART was defined as ART initiation within 6 months of HIV acquisition; others were classified as late-ART or unknown. Median age was 42 years, 91% male, 75% white, 45% received early-ART. Median time to pVL >50, >400, and >10,000 copies/mL was 16 days (interquartile range [IQR]:13-25), 21 (IQR:15-28), and 32 (IQR:20-35), respectively. PTC defined as pVL <50 copies/mL at day 84 occurred in 4% (n = 14) of participants (6% early-ART and 1% late-ART). Sustained PTC of pVL <50 copies/ml after 84 days is rare in PWH, especially in those starting ART late. Our findings inform future interventional HIV cure/remission trials on study size and design.

Advances in the mathematical modeling of posttreatment control of HIV-1

PURPOSE OF REVIEW

Several new intervention strategies have shown significant improvements over antiretroviral therapy (ART) in eliciting lasting posttreatment control (PTC) of HIV-1. Advances in mathematical modelling have offered mechanistic insights into PTC and the workings of these interventions. We review these advances.

RECENT FINDINGS

Broadly neutralizing antibody (bNAb)-based therapies have shown large increases over ART in the frequency and the duration of PTC elicited. Early viral dynamics models of PTC with ART have been advanced to elucidate the underlying mechanisms, including the role of CD8+ T cells. These models characterize PTC as an alternative set-point, with low viral load, and predict routes to achieving it. Large-scale omic datasets have offered new insights into viral and host factors associated with PTC. Correspondingly, new classes of models, including those using learning techniques, have helped exploit these datasets and deduce causal links underlying the associations. Models have also offered insights into therapies that either target the proviral reservoir, modulate immune responses, or both, assessing their translatability.

SUMMARY

Advances in mathematical modeling have helped better characterize PTC, elucidated and quantified mechanisms with which interventions elicit it, and informed translational efforts.

Definition of Virological Endpoints Improving the Design of HIV Cure Strategies Using Analytical Antiretroviral Treatment Interruption

BACKGROUND

Analytical treatment interruption (ATI) is the gold standard in HIV research for assessing the capability of new therapeutic strategies to control viremia without antiretroviral treatment (ART). The viral setpoint is commonly used as endpoint to evaluate their efficacy. However, in line with recommendations from a consensus meeting, to minimize the risk of increased viremia without ART, trials often implement short ATI phases and stringent virological ART restart criteria. This approach can limit the accurate observation of the setpoint.

METHODS

We analyzed viral dynamics in 235 people with HIV from 3 trials, examining virological criteria during ATI phases. Time-related (eg time to rebound, peak, and setpoint) and viral load magnitude-related criteria (peak, setpoint, and time-averaged AUC [nAUC]) were described. Spearman correlations were analyzed to identify (1) surrogate endpoints for setpoint and (2) optimal virological ART restart criteria mitigating the risks of ART interruption and the evaluation of viral control.

RESULTS

Comparison of virological criteria between trials showed strong dependencies on ATI design. Similar correlations were found across trials, with nAUC the most strongly correlated with the setpoint, with correlations >0.70. A threshold >100 000 copies/mL for 2 consecutive measures is requested as a virological ART restart criterion.

CONCLUSIONS

Our results are in line with recommendations and emphasize the benefits of an ATI phase >12 weeks, with regular monitoring, and a virological ART restart criterion of 10 000 copies/mL to limit the risk for patients while capturing enough information to keep nAUC as an optimal proxy to the setpoint.

Enhancing broadly neutralising antibody suppression of HIV by immune modulation and vaccination

Although HIV infection can be managed with antiretroviral drugs, there is no cure and therapy has to be taken for life. Recent successes in animal models with HIV-specific broadly neutralising antibodies (bNAbs) have led to long-term virological remission and even possible cures in some cases. This has resulted in substantial investment in human studies to explore bNAbs as a curative intervention for HIV infection. Emerging data are encouraging, but suggest that combinations of bNAbs with other immunomodulatory agents may be needed to induce and sustain long-term viral control. As a result, a number of clinical trials are currently underway exploring these combinations. If successful, the impact for the millions of people living with HIV could be substantial. Here, we review the background to the use of bNAbs in the search for an HIV cure and how different adjunctive agents might be used together to enhance their efficacy.

Impact of antiretroviral therapy during primary HIV infection on T-cell immunity after treatment interruption

This study aims to understand the impact of early antiretroviral therapy (ART) on HIV-specific T-cell responses measured after treatment interruption, which may inform strategies to deliver ART-free immune-mediated viral suppression. HIV-specific T-cell immunity was analysed using gamma interferon enzyme-linked immunospot assays in two studies. SPARTAC included individuals with primary HIV infection randomised to 48 weeks of ART (n = 24) or no immediate therapy (n = 37). The PITCH (n = 7) cohort started antiretroviral therapy in primary infection for at least one year, followed by TI. In SPARTAC, participants treated in PHI for 48 weeks followed by TI for 12 weeks, and those who remained untreated for 60 weeks made similar HIV Gag-directed responses (both magnitude and breadth) at week 60. However, the treated group made a greater proportion of novel HIV Gag-directed responses by Week 60, suggestive of a greater reserve to produce new potentially protective responses. In the more intensively followed PITCH study, 6/7 participants showed dominant Gag and/or Pol-specific responses post-TI compared with pre-TI. Although early ART in PHI was not associated with major differences in HIV-specific immunity following TI compared with untreated participants, the potential to make more new Gag-directed responses warrants further investigation as this may inform strategies to achieve ART-free control.

International AIDS society conference 2023 summary

AIM

This article summarizes key research presented at the International AIDS Society (IAS) Conference in Brisbane, held in July 2023.

CO-MORBIDITIES

The REPRIEVE Trial as a conference highlight, demonstrating significantly fewer major cardiovascular events amongst people with HIV who were randomized to pitavastatin compared to placebo. Key data on weight, hypertension and incident diabetes are also summarized.

ANTIRETROVIRAL THERAPY

Novel data on doravirine and islatravir are described as are trials demonstrating efficacy dolutegravir/lamivudine first-line in people without baseline resistance testing and in suppressed switch amongst people with historic lamivudine resistance.

HIV CURE

The sixth case of HIV cure secondary to stem cell transplantation is summarized, as are new insights into the central nervous system as an HIV reservoir.

Recent Advances Using Genetic Therapies Against Infectious Diseases and for Vaccination

The development of prophylatic or therapeutic medicines for infectious diseases is one of the priorities for health organizations worldwide. Innovative solutions are required to achieve effective, safe, and accessible treatments for most if not all infectious diseases, particularly those that are chronic in nature or that emerge unexpectedly over time. Genetic technologies offer versatile possibilities to design therapies against pathogens. Recent developments such as mRNA vaccines, CRISPR gene editing, and immunotherapies provide unprecedented hope to achieve significant results in the field of infectious diseases. This review will focus on advances in this domain, showcasing the cross-fertilization with other fields (e.g., oncology), and addressing some of the logistical and economic concerns important to consider when making these advances accessible to diverse populations around the world.

Vaccinal effect of HIV-1 antibody therapy: dream or reality?

PURPOSE OF REVIEW

This review summarizes recent studies reporting the induction of vaccinal effects by human immunodeficiency virus (HIV-1) antibody therapy. It also puts into perspective preclinical studies that have identified mechanisms involved in the immunomodulatory properties of antiviral antibodies. Finally, it discusses potential therapeutic interventions to enhance host adaptive immune responses in people living with HIV (PLWH) treated with broadly neutralizing antibodies (bNAbs).

RECENT FINDINGS

Recent studies in promising clinical trials have shown that, in addition to controlling viremia, anti-HIV-1 bNAbs are able to enhance the host's humoral and cellular immune response. Such vaccinal effects, in particular the induction of HIV-1-specific CD8 + T-cell responses, have been observed upon treatment with two potent bNAbs (3BNC117 and 10-1074) alone or in combination with latency-reversing agents (LRA). While these studies reinforce the idea that bNAbs can induce protective immunity, the induction of vaccinal effects is not systematic and might depend on both the virological status of the patient as well as the therapeutic strategy chosen.

SUMMARY

HIV-1 bNAbs can enhance adaptive host immune responses in PLWH. The challenge now is to exploit these immunomodulatory properties to design optimized therapeutic interventions to promote and enhance the induction of protective immunity against HIV-1 infection during bNAbs therapy.