HIV-1 DNA decay dynamics in early treated individuals: practical considerations for clinical trial design.

BACKGROUND: Initiation of combination antiretroviral therapy (cART) soon after HIV-1 infection limits the establishment of viral reservoirs. Thus, early treated individuals are preferred candidates to evaluate novel viral remission strategies. However, their cART-dependent HIV-1 DNA decay dynamics are still poorly defined. This can hamper the design and interpretation of results from clinical trials intended to further reduce viral reservoirs. OBJECTIVES: To clarify the duration of cART needed for the HIV-1 reservoir to be stabilized in early treated individuals. METHODS: We characterized the longitudinal decline of total HIV-1 DNA levels by droplet digital PCR in 21 individuals initiating cART within 6 months after estimated HIV-1 acquisition. Measurements were taken at cART initiation, after 6 months and annually until Year 4. Correlations between virological and clinical parameters were statistically analysed. Statistical modelling was performed applying a mixed-effects model. RESULTS: Total HIV-1 DNA experienced a median overall decrease of 1.43 log10 units (IQR = 1.17-1.69) throughout the 4 years of follow-up. Baseline levels for total HIV-1 DNA, viral load, absolute CD4+ T cell count and CD4+/CD8+ ratio correlate with final HIV-1 DNA measurements (R2 = 0.68, P < 0.001; R2 = 0.54, P = 0.012; R2 = -0.47, P = 0.031; and R2 = -0.59, P = 0.0046, respectively). Statistical modelling shows that after 2 years on cART the viral reservoir had reached a set point. CONCLUSIONS: A waiting period of 2 years on cART should be considered when designing interventions aiming to impact latent HIV-1 reservoir levels and viral rebound kinetics after cART discontinuation, in order to facilitate interpretation of results and enhance the chance of viral control.

Corrigendum to 'Therapeutic vaccination refocuses T-cell responses towards conserved regions of HIV-1 in early treated individuals (BCN 01 study)' EClinicalMedicine 11 (2019) 65-80.

[This corrects the article DOI: 10.1016/j.eclinm.2019.05.009.].

Therapeutic Vaccination Refocuses T-cell Responses Towards Conserved Regions of HIV-1 in Early Treated Individuals (BCN 01 study).

BACKGROUND: Strong and broad antiviral T-cell responses targeting vulnerable sites of HIV-1 will likely be a critical component for any effective cure strategy. METHODS: BCN01 trial was a phase I, open-label, non-randomized, multicenter study in HIV-1-positive individuals diagnosed and treated during early HIV-1 infection to evaluate two vaccination regimen arms, which differed in the time (8 versus 24 week) between the ChAdV63.HIVconsv prime and MVA.HIVconsv boost vaccinations. The primary outcome was safety. Secondary endpoints included frequencies of vaccine-induced IFN-γ+ CD8+ T cells, in vitro virus-inhibitory capacity, plasma HIV-1 RNA and total CD4+ T-cells associated HIV-1 DNA. (NCT01712425). FINDINGS: No differences in safety, peak magnitude or durability of vaccine-induced responses were observed between long and short interval vaccination arms. Grade 1/2 local and systemic post-vaccination events occurred in 22/24 individuals and resolved within 3 days. Weak responses to conserved HIV-1 regions were detected in 50% of the individuals before cART initiation, representing median of less than 10% of their total HIV-1-specific T cells. All participants significantly elevated these subdominant T-cell responses, which after MVA.HIVconsv peaked at median (range) of 938 (73-6,805) IFN-γ SFU/106 PBMC, representing on average 58% of their total anti-HIV-1 T cells. The decay in the size of the HIV-1 reservoir was consistent with the first year of early cART initiation in both arms. INTERPRETATION: Heterologous prime-boost vaccination with ChAdV63-MVA/HIVconsv was well-tolerated and refocused pre-cART T-cell responses towards more protective epitopes, in which immune escape is frequently associated with reduced HIV-1 replicative fitness and which are common to most global HIV-1 variants. FUNDING: HIVACAT Catalan research program for an HIV vaccine and Fundació Gloria Soler. Vaccine manufacture was jointly funded by the Medical Research Council (MRC) UK and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreements (G0701669. RESEARCH IN CONTEXT: Evidence Before this Study: T cells play an important role in the control of HIV infection and may be particularly useful for HIV-1 cure by killing cells with reactivated HIV-1. Evidence is emerging that not all T-cell responses are protective and mainly only those targeting conserved regions of HIV-1 proteins are effective, but typically immunologically subdominant, while those recognizing hypervariable, easy-to-escape immunodominant 'decoys' do not control viremia and do not protect from a loss of CD4 T cells. We pioneered a vaccine strategy focusing T-cell responses on the most conserved regions of the HIV-1 proteome using an immunogen designated HIVconsv. T cells elicited by the HIVconsv vaccines in HIV-uninfected UK and Kenyan adults inhibited in vitro replication of HIV-1 isolates from 4 major global clades A, B, C and D.Added Value of this Study: The present study demonstrated the concept that epitopes subdominant in natural infection, when taken out of the context of the whole HIV-1 proteome and presented to the immune system by a potent simian adenovirus prime-poxvirus MVA boost regimen, can induce strong responses in patients on antiretroviral treatment and efficiently refocus HIV-1-specific T-cells to the protective epitopes delivered by the vaccine.Implications of all the Available Evidence: Nearly all HIV-1 vaccine strategies currently emphasize induction of broadly neutralizing Abs. The HIVconsv vaccine is one of a very few approaches focussing exclusively on elicitation of T cells and, therefore, can complement antibody induction for better prevention and cure. Given the cross-clade reach on the HIVconsv immunogen design, if efficient, the HIVconsv vaccines could be deployed globally. Effective vaccines will likely be a necessary component in combination with other available preventive measures for halting the HIV-1/AIDS epidemic.

Mechanisms of Abrupt Loss of Virus Control in a Cohort of Previous HIV Controllers.

Elite and viremic HIV controllers are able to control their HIV infection and maintain undetectable or low-level viremia in the absence of antiretroviral treatment. Despite extensive studies, the immune factors responsible for such exclusive control remain poorly defined. We identified a cohort of 14 HIV controllers that suffered an abrupt loss of HIV control (LoC) to investigate possible mechanisms and virological and immunological events related to the sudden loss of control. The in-depth analysis of these subjects involved the study of cell tropism of circulating virus, evidence for HIV superinfection, cellular immune responses to HIV, as well as an examination of viral adaptation to host immunity by Gag sequencing. Our data demonstrate that a poor capacity of T cells to mediate in vitro viral suppression, even in the context of protective HLA alleles, predicts a loss of viral control. In addition, the data suggest that inefficient viral control may be explained by an increase of CD8 T-cell activation and exhaustion before LoC. Furthermore, we detected a switch from C5- to X4-tropic viruses in 4 individuals after loss of control, suggesting that tropism shift might also contribute to disease progression in HIV controllers. The significantly reduced inhibition of in vitro viral replication and increased expression of activation and exhaustion markers preceding the abrupt loss of viral control may help identify untreated HIV controllers that are at risk of losing control and may offer a useful tool for monitoring individuals during treatment interruption phases in therapeutic vaccine trials.IMPORTANCE A few individuals can control HIV infection without the need for antiretroviral treatment and are referred to as HIV controllers. We have studied HIV controllers who suddenly lose this ability and present with high in vivo viral replication and decays in their CD4+ T-cell counts to identify potential immune and virological factors that were responsible for initial virus control. We identify in vitro-determined reductions in the ability of CD8 T cells to suppress viral control and the presence of PD-1-expressing CD8+ T cells with a naive immune phenotype as potential predictors of in vivo loss of virus control. The findings could be important for the clinical management of HIV controller individuals, and it may offer an important tool to anticipate viral rebound in individuals in clinical studies that include combination antiretroviral therapy (cART) treatment interruptions and which, if not treated quickly, could pose a significant risk to the trial participants.

Virological and immunological outcome of treatment interruption in HIV-1-infected subjects vaccinated with MVA-B.

The most relevant endpoint in therapeutic HIV vaccination is the assessment of time to viral rebound or duration of sustained control of low-level viremia upon cART treatment cessation. Structured treatment interruptions (STI) are however not without risk to the patient and reliable predictors of viral rebound/control after therapeutic HIV-1 vaccination are urgently needed to ensure patient safety and guide therapeutic vaccine development. Here, we integrated immunological and virological parameters together with viral rebound dynamics after STI in a phase I therapeutic vaccine trial of a polyvalent MVA-B vaccine candidate to define predictors of viral control. Clinical parameters, proviral DNA, host HLA genetics and measures of humoral and cellular immunity were evaluated. A sieve effect analysis was conducted comparing pre-treatment viral sequences to breakthrough viruses after STI. Our results show that a reduced proviral HIV-1 DNA at study entry was independently associated with two virological parameters, delayed HIV-1 RNA rebound (p = 0.029) and lower peak viremia after treatment cessation (p = 0.019). Reduced peak viremia was also positively correlated with a decreased number of HLA class I allele associated polymorphisms in Gag sequences in the rebounding virus population (p = 0.012). Our findings suggest that proviral DNA levels and the number of HLA-associated Gag polymorphisms may have an impact on the clinical outcome of STI. Incorporation of these parameters in future therapeutic vaccine trials may guide refined immunogen design and help conduct safer STI approaches.

Alternative effector-function profiling identifies broad HIV-specific T-cell responses in highly HIV-exposed individuals who remain uninfected.

The characterization of host immune responses to human immunodeficiency virus (HIV) in HIV controllers and individuals with high exposure but seronegativity to HIV (HESN) is needed to guide the development of effective preventive and therapeutic vaccine candidates. However, several technical hurdles severely limit the definition of an effective virus-specific T-cell response. By using a toggle-peptide approach, which takes HIV sequence diversity into account, and a novel, boosted cytokine staining/flow cytometry strategy, we here describe new patterns of T-cell responses to HIV that would be missed by standard assays. Importantly, this approach also allows detection of broad and strong virus-specific T-cell responses in HESN individuals that are characterized by a T-helper type 1 cytokine-like effector profile and produce cytokines that have been associated with potential control of HIV infection, including interleukin 10, interleukin 13, and interleukin 22. These results establish a novel approach to improve the current understanding of HIV-specific T-cell immunity and identify cellular immune responses and individual cytokines as potential markers of relative HIV resistance. As such, the findings also help develop similar strategies for more-comprehensive assessments of host immune responses to other human infections and immune-mediated disorders.

Long-term effectiveness of infrared coagulation for the treatment of anal intraepithelial neoplasia grades 2 and 3 in HIV-infected men and women.

AIMS: To assess the effectiveness and safety of infrared coagulation (IRC) for the ablation of anal intraepithelial neoplasia (AIN) and to provide data on the prevalence of AIN in HIV-infected patients. PATIENTS AND METHODS: We performed a single-center, retrospective cohort study based on data collected from a prospectively compiled database of outpatients attended in the Clinical-Proctology-HIV-Unit (first visit). The effectiveness (normal anal cytology after 12 months of IRC) and safety of IRC were estimated. RESULTS: Between January 2005 and December 2011, a total of 69 (5%) patients with biopsy-proven AIN-2 or AIN-3 from among 1518 patients (1310 men; 208 women) were treated with IRC. The prevalence of cytological abnormalities was 49.5% [751/1518; (atypical squamous cells of unknown significance, 14%; low-grade squamous intraepithelial lesions, 27.5%; high-grade squamous intraepithelial lesions, 8%)]. High-resolution anoscopy revealed intra-anal condylomata in 31% of patients (236/751), nonvisualized lesions in 30% (227/751), and visualized lesions (from which biopsy specimens were taken) in 38% (288/751). The histological diagnosis was: AIN-1, 52% (151/288); AIN-2, 15% (44/288); AIN-3, 9% (25/288); normal, 19% (56/288); and nonevaluable, 4% (12/288). IRC was applied in-office in 66 patients (three refused to undergo treatment). At 12 months, all patients (n = 56) had a normal anal cytology result. Seven (13%) patients had biopsy-proven recurrence [mean (range) time-to-recurrence, 30 (18-43) months]. High-risk-human papilloma virus (HPV) infection was detected in all anal lesions (HPV-16 was the most common genotype). Agreement between cytological and histological results was poor. CONCLUSION: A high prevalence of AIN was found in both HIV-infected men and HIV-infected women. Although randomized clinical trials are lacking, IRC ablation of AIN-2 and AIN-3 lesions without concomitant condylomata could help prevent anal squamous cell carcinoma.

Natural history of human papillomavirus infections involving anal, penile, and oral sites among HIV-positive men.

AIM: The aim of this study was to characterize the natural history of human papillomavirus (HPV) infection at anal canal, penile, and oral sites in HIV-positive men based on their sexual behavior. METHODS: This is a single-center, prospective cohort study. The prevalence, clearance, and incidence of HPV infection at anal, penile, and oral sites were studied in HIV-positive men who have sex with men (MSM) and heterosexual individuals using multiplex polymerase chain reaction. Risk factors associated with HPV infection were analyzed. RESULTS: In total, 733 patients (538 MSM, 195 heterosexual) were included in the study between 2005 and 2009. The prevalence, clearance, and incidence of HPV infection were 73%, 30%, and 36% at anal site; 26%, 56%, and 17% at penile site; and 16%, 44%, and 11% at oral site, respectively. At anal site, MSM had a higher HPV prevalence (84% vs. 42%; odds ratio,7.3; 95% confidence interval [CI], 5.2-10.6) mainly for multiple (≥3) HPV types, higher incidence rate (324 vs. 92 new HPV-infected person per 1000 person-years [hazard ratio, 8.1; 95% CI, 3.8-17.3]), and a lower clearance rate (125 vs. 184 cleared HPV-infected person per 1000 person-years [hazard ratio, 0.5; 95% CI, 0.3-0.9]) than did heterosexuals. Similar prevalence, clearance, and incidence rates of penile and oral HPV infection were found between groups. The most common high-risk HPV type for the 3 body sites studied was the HPV-16. Finally, a similar proportion of heterosexuals (7%) and MSM (6%) presented concurrent HPV infections (anal-penile-oral sites). History of anal warts was associated with higher HPV prevalence in the 3 body parts. CONCLUSIONS: Although MSM presented the highest risk of anal HPV infection, heterosexual men also showed a remarkable prevalence of anal HPV infection and a comparable risk to MSM for penile and oral HPV infection. Taking into account all these results, the careful inspection of the anal canal, penile, and oral sites should at least be routine in each clinic visit of HIV-infected men independently of their sexual behavior.