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

Antiretroviral therapy is not curative. Given the challenges in providing lifelong therapy to a global population of more than 35 million people living with HIV, there is intense interest in developing a cure for HIV infection. The International AIDS Society convened a group of international experts to develop a scientific strategy for research towards an HIV cure. This Perspective summarizes the group's strategy.

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The primary analysis of the FLAMINGO study at 48 weeks showed that patients taking dolutegravir once daily had a significantly higher virological response rate than did those taking ritonavir-boosted darunavir once daily, with similar tolerability. We present secondary efficacy and safety results analysed at 96 weeks.

HIV-1 replication depends on the state of cell activation and division. It is established that SAMHD1 restricts HIV-1 infection of resting CD4T cells. The modulation of SAMHD1 expression during T-cell activation and proliferation, however, remains unclear, as well as a role for SAMHD1 during HIV-1 pathogenesis.

Dolutegravir has been shown to be non-inferior to an integrase inhibitor and superior to a non-nucleoside reverse transcriptase inhibitor (NNRTI). In FLAMINGO, we compared dolutegravir with darunavir plus ritonavir in individuals naive for antiretroviral therapy.

To compare the safety and efficacy of the two single-tablet regimens (STRs), rilpivirineemtricitabinetenofovir disoproxil fumarate (RPVFTCTDF) and efavirenzemtricitabinetenofovir DF (EFVFTCTDF), in HIV-1-infected, treatment-naive adults.

Background In Africa, success of antiretroviral treatment (ART) seems to lag behind in children compared with adults, and high therapeutic failure rates have been reported. We aimed to identify prevalence and determinants of virological failure in HIV-infected children treated under programmatic conditions.Methods All patients <18 years on ART presenting to the HIV clinic at the Bamenda Regional Hospital, a secondary referral hospital in rural Cameroon, from September 2010 to August 2011, were enrolled in this cross-sectional study. Clinical data, self-reported adherence, CD4+T-cell counts and viral load were recorded. Therapeutic drug monitoring was performed on stored plasma samples. Determinants of virological failure were identified using descriptive statistics and logistic regression.Results A total of 230 children with a mean age of 8.9 years (sd 3.7) were included. At the time of analysis, the mean duration of HAART was 3.5 years (sd 1.7) and 12% had a CD4+T-cell count <200 cells/µl. In total, 53% of children experienced virological failure (>200 copies/ml). Among children on nevirapine (NVP), plasma levels were subtherapeutic in 14.2% and supratherapeutic in 42.2%. Determinants of virological failure included male sex, lower CD4+T-cell counts, subtherapeutic drug levels, longer time on ART and a deceased mother. Poor adherence was associated with subtherapeutic NVP plasma levels and advanced disease stages (WHO stage 3/4).Conclusions This study demonstrates high virological failure rates and a high variability of NVP plasma levels among HIV-infected children in a routine ART programme in rural Cameroon. Strategies to improve adherence to ART in HIV-infected children are urgently needed.

Antiretroviral therapy for HIV infection needs lifelong access and strict adherence to regimens that are both expensive and associated with toxic effects. A curative intervention will be needed to fully stop the epidemic. The failure to eradicate HIV infection during long-term antiretroviral therapy shows the intrinsic stability of the viral genome in latently infected CD4T cells and other cells, and possibly a sustained low-level viral replication. Heterogeneity in latently infected cell populations and homoeostatic proliferation of infected cells might affect the dynamics of virus production and persistence. Despite potent antiretroviral therapy, chronic immune activation, inflammation, and immune dysfunction persist, and are likely to have important effects on the size and distribution of the viral reservoir. The inability of the immune system to recognise cells harbouring latent virus and to eliminate cells actively producing virus is the biggest challenge to finding a cure. We look at new approaches to unravelling the complex virus–host interactions that lead to persistent infection and latency, and discuss the rationale for combination of novel treatment strategies with available antiretroviral treatment options to cure HIV.

BackgroundRecently, more clinical trials are being conducted in Africa and Asia, therefore, background morbidity in the respective populations is of interest. Between 2000 and 2007, the International AIDS Vaccine Initiative sponsored 19 Phase 1 or 2A preventive HIV vaccine trials in the US, Europe, Sub-Saharan Africa and India, enrolling 900 healthy HIV-1 uninfected volunteers.ObjectiveTo assess background morbidity as reflected by unsolicited adverse events (AEs), unrelated to study vaccine, reported in clinical trials from four continents.MethodsAll but three clinical trials were double-blind, randomized and placebo-controlled. Study procedures and data collection methods were standardized. The frequency and severity of AEs reported during the first year of the trials were analyzed. To avoid confounding by vaccine-related events, solicited reactogenicity and other AEs occurring within 28 d after any vaccination were excluded.ResultsIn total, 2134 AEs were reported by 76% of all participants; 73% of all events were mild. The rate of AEs did not differ between placebo and vaccine recipients. Overall, the percentage of participants with any AE was higher in Africa (83%) compared with Europe (71%), US (74%) and India (65%), while the percentage of participants with AEs of moderate or greater severity was similar in all regions except India. In all regions, the most frequently reported AEs were infectious diseases, followed by gastrointestinal disorders.ConclusionsDespite some regional differences, in these healthy participants selected for low risk of HIV infection, background morbidity posed no obstacle to clinical trial conduct and interpretation. Data from controlled clinical trials of preventive interventions can offer valuable insights into the health of the eligible population.

AIDS-related lymphomas (ARLs) significantly contribute to mortality in HIV-infected patients. Optimal chemotherapy treatment and the use of rituximab remain controversial. The aim of the present cohort study was to analyze the outcome of HIV-infected patients diagnosed with ARL, with regard to the use of rituximab, clinical characteristics and histopathological markers.

Although HIV-associated multicentric Castleman disease (HIV-MCD) is not classified as an AIDS-defining illness, mortality is high and progression to lymphoma occurs frequently. At present, there is no widely accepted recommendation for the treatment of HIV-MCD. In this retrospective (1998-2010), multicentric analysis of 52 histologically proven cases, outcome was analyzed with respect to the use of different MCD therapies and potential prognostic factors. After a mean follow-up of 2.26 years, 19 of 52 patients died. Median estimated overall survival (OS) was 6.2 years. Potential risk factors, such as older age, previous AIDS, or lower CD4 T cells had no impact on OS. Treatment was heterogeneous, consisting of cytostatic and/or antiviral agents, rituximab, or combinations of these modalities. There were marked differences in the outcome when patients were grouped according to MCD treatment. Patients receiving rituximab-based regimens had higher complete remission rates than patients receiving chemotherapy only. The mean estimated OS in patients receiving rituximab alone or in combination with cytostatic agents was not reached, compared with 5.1 years (P= .03). Clinical outcome and overall survival of HIV-MCD have markedly improved with rituximab-based therapies, considering rituximab-based therapies (with or without cytostatic agents) to be among the preferred first-line options in patients with HIV-MCD.

Although HIV-associated multicentric Castleman disease (HIV-MCD) is not classified as an AIDS-defining illness, mortality is high and progression to lymphoma occurs frequently. At present, there is no widely accepted recommendation for the treatment of HIV-MCD. In this retrospective (1998-2010), multicentric analysis of 52 histologically proven cases, outcome was analyzed with respect to the use of different MCD therapies and potential prognostic factors. After a mean follow-up of 2.26 years, 19 of 52 patients died. Median estimated overall survival (OS) was 6.2 years. Potential risk factors, such as older age, previous AIDS, or lower CD4 T cells had no impact on OS. Treatment was heterogeneous, consisting of cytostatic and/or antiviral agents, rituximab, or combinations of these modalities. There were marked differences in the outcome when patients were grouped according to MCD treatment. Patients receiving rituximab-based regimens had higher complete remission rates than patients receiving chemotherapy only. The mean estimated OS in patients receiving rituximab alone or in combination with cytostatic agents was not reached, compared with 5.1 years (P = .03). Clinical outcome and overall survival of HIV-MCD have markedly improved with rituximab-based therapies, considering rituximab-based therapies (with or without cytostatic agents) to be among the preferred first-line options in patients with HIV-MCD.

Carrier-mediated transport across cell membranes is an important determinant of activity, resistance, and toxicity of chemotherapeutic agents including antiretroviral (ARV) drugs (ARDs). The organic cation transporters (OCTs) 1 and 2 have been implicated in the translocation of different cationic drugs but so far were insufficiently tested for interactions with ARDs. Here, we assessed among cationic drugs commonly used in human immunodeficiency virus (HIV) therapy inhibitors and substrates of OCTs, and analyzed the tissue distribution of OCTs and their expression in lymph nodes (LNs), the primary intracellular target of HIV and ARDs. Inhibitors were identified by measuring the attenuated uptake of the radiolabeled model substrate 1-methyl-4-phenylpyridinium into OCT-transfected human embryonic kidney-293 cells in the presence of ARDs. Substrates were identified by measuring OCT-specific intracellular accumulation using liquid chromatography/tandem mass spectrometry. Inhibitory drugs were (in order of increasing potency): nelfinavir < ritonavir < saquinavir < indinavir < trimethoprim < pentamidine, with consistently lower IC50values determined for OCT1. Substrates with highest transport efficacy (Vmax/Km) were lamivudine (OCT1, 8 µl/mg protein/min; OCT2, 4.4 µl/mg protein/min) and zalcitabine (OCT1, 4.1 µl/mg protein/min; OCT2, 2.6 µl/mg protein/min). Using quantitative real-time polymerase chain reaction, a marked expression level of OCT1 was detected in human samples of liver, ovary, prostate, and testis, and of OCT2 in kidney, colon, heart, skeletal muscle, and testis. Expression of OCTs in LNs was low in HIV-negative control individuals but dramatically increased in HIV-infected persons. These data suggest that drug interactions about the OCTs may be relevant for the ARV therapy, in particular by influencing drug accession to infected tissues and hepatic or renal elimination.

Background The aim of the study was to investigate the incidence of abacavir-related hypersensitivity reaction (HSR) and associated deaths in EuroSIDA HIV-1-infected patients.Methods Poisson regression models were developed to compare incidence of abacavir discontinuation according to the line of therapy within which abacavir was received, geographical regions, calendar time and drug formulation (abacavir/lamivudine combination tablet versus abacavir as a single drug or abacavir/zidovudine/ lamivudine combination).Results Of 3,278 patients that started abacavir, 2,101 (64.1%) discontinued. Of these, 167 (5.1%) discontinued abacavir within 3 months due to HSR with an incidence of 22.1 (95% confidence interval [CI] 18.7–25.4) per 100 person-years of follow-up. After adjustment for gender, prior AIDS, hepatitis C serostatus, baseline CD4+T-cell count, region and calendar time, HSR incidence was significantly higher in those starting abacavir in a first-line regimen compared with second-line (incidence rate ratio [IRR] 2.04 [95% CI 1.24–3.38]; P=0.005). There was no significant difference between regions. HSR incidence from 2005 onwards was significantly lower compared with 1999–2000 (IRR 0.54 [95% CI 0.32–0.92]; P=0.024). There was a lower observed incidence in patients starting abacavir/lamivudine compared with other formulations (IRR 0.33 [95% CI 0.13 –0.88]; P=0.027), however, available data were limited.Conclusions Incidence of abacavir-related HSR is higher in patients starting abacavir in first-line therapy, which could indicate increased over-diagnosis. HSR incidence has decreased in recent years, which might reflect the wider availability of genetic screening and improved awareness of symptoms. There were no reported deaths due to abacavir HSR.

Antiviral drug therapy can effectively suppress HIV replication, but emerging viral resistance and drug toxicity limit long-term therapeutic efficacy. In addition, regeneration of the T helper cell repertoire is often incomplete. The current major challenges in the treatment of HIV infection are therefore the reconstitution of cellular immunity, and especially of the HIV-specific immune response, and the suppression of virus replication in patients with HAART failure. Several gene therapeutic strategies for immune reconstitution of AIDS patients have been described. Preclinical and clinical studies have examined the safety and efficacy of two basic approaches: firstly, the transfer of autologous T cells armed with recombinant receptors that target HIV antigens to specifically increase antiviral immunity and, secondly, the transfer of genetically modified T cells or hematopoietic progenitor cells that express an antiviral gene. However, for both approaches, engraftment levels of gene-modified cells have not been sufficient to reconstitute cellular immunity and to effectively reduce the overall viral load in patients. Strategies to improve the technologies and procedures involved in gene therapeutic immune reconstitution of AIDS patients are discussed.

Highly active antiretroviral therapy rapidly reduces virus replication in the lymphoid tissue. Production of viral RNA, however, may still be detected in the lymphoid tissue despite negative plasma viremia. Continuing virus production and latent infection in resting cells seem to be important factors for viral rebound following treatment interruption. In parallel with viral suppression, immune activation is decreased and CD4 T cell counts in the lymphoid tissue increase. It is still not known if there is a potential for complete viral suppression and immune reconstitution. Analyses of the lymphoid tissue during therapy may be helpful in addressing these issues.

ABSTRACTThe prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n= 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1.6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.

Objective To investigate the antiviral activity of abacavir added to stable background therapy. Design: Retrospective analysis.Materials and Methods In 27 subjects with detectable plasma viraemia during stable treatment abacavir was added as the only agent. Patients were pre-treated for 180 weeks (mean) with regimens containing zidovudine (102 weeks) and lamivudine (88 weeks). Results were analysed in two groups: group 1, >400 HIV RNA copies/ml; group 2, 25–399 copies/ml. In 7/13 group 1 patients genotypic resistance analysis was performed prior to abacavir.Results Median follow-up was 28 weeks, median HIV RNA load at baseline 2.48 log10copies/ml (3.52 and 1.66 log10copies/ml in groups 1 and 2, respectively). Plasma viraemia was reduced to less than 400 HIV RNA copies/ml in 2/13 subjects in group 1 and 11/11 in group 2 (week 24). Only one patient in group 1 responded transiently to less than 25 HIV RNA copies/ml. In contrast, 10/14 and 11/11 in group 2 reached values below this threshold at weeks 12 and 24, respectively. Overall, 7/13 group 1 patients were found with =2 zidovudine resistance-associated mutations. The lamivudine resistance-associated mutation M184V was present in four of seven cases. All of these patients showed only a moderate and transient reduction of plasma viraemia (medium peak reduction of 0.73 log10after 20 weeks).Conclusions The addition of abacavir during low-level treatment failure may restore or achieve suppression to levels below the cut-off of the ultrasensitive PCR.

The role of the thymus in HIV-1 pathogenesis remains unclear. We developed an assay to quantify the number of recent thymic emigrants in blood based on the detection of a major excisional DNA byproduct (termed α1 circle) of T cell receptor rearrangement. By studying 532 normal individuals, we found that α1 circle numbers in blood remain high for the first 10–15 yr of life, a sharp drop is seen in the late teen years, and a gradual decline occurs thereafter. Compared with age-matched uninfected control individuals, α1 circle numbers in HIV-1–infected adults were significantly reduced; however, there were many individuals with normal α1 circle numbers. In 74 individuals receiving highly active antiretroviral therapy, we found no appreciable effect on α1 circle numbers in those whose baseline values were already within the normal range, but significant increases were observed in those with a preexisting impairment. The increases in α1 circle numbers were, however, numerically insufficient to account for the rise in levels of naive T lymphocytes. Overall, it is difficult to invoke thymic regenerative failure as a generalized mechanism for CD4 lymphocyte depletion in HIV-1 infection, as α1 circle numbers are normal in a substantial subset of HIV-1–infected individuals.

Objective To study decay rates of productively and latently infected cells in peripheral blood and lymph nodes during triple antiretroviral therapy and the possible impact of interleukin-2 (IL-2) on viral kinetics. Methods: In this non-randomized study, nine antiretro-viral-naive HIV-positive patients received either saquinavir hard gel capsules 2400 mg three times daily (group I; four patients) or saquinavir soft gel capsules 1200 mg three times daily and IL-2 (group II), in both cases together with two nucleoside analogues. Plasma viraemia and lymphocyte subsets were analysed. Axillary lymph nodes were excised before and after 12 weeks of therapy. Lymph node sections were examined by in situhybridization for HIV RNA, and productively infected cells were counted. Infection rates of FACS-sorted CD3, CD4 lymph node and peripheral blood mononuclear cells were determined by nested DNA PCR.Results Baseline plasma HIV RNA levels ranged from <25 to >1x106copies/ml and remained undetectable throughout the study in one patient in group I. Plasma viraemia became undetectable after 3 months in four patients (three in group I). Productively infected cells were markedly reduced in the follow-up lymph node specimens. HIV DNA-positive CD4 T cells were reduced in lymphoid tissue and peripheral blood in all six evaluable patients. There were no significant differences between the groups in the clearance rates of plasma virus and of HIV DNA-positive cells.Conclusions Combined antiretroviral therapy rapidly suppressed active HIV replication in plasma and lymphoid tissue. Latently infected cells were cleared at a slower rate. Viral clearance did not appear to be markedly affected by additional IL-2 therapy.

The efficacy of triple drug therapy for HIV-1 infection encourages its early use to prevent damage to the immune system. We monitored the effects of such therapy on 12 patients with 14–75-mo histories of minimal disease, i.e., CD4+ counts constantly >500/μl and little or no lymph node enlargement. In this way, we could first determine the extent of viral replication and immunoarchitectural changes in unenlarged nodes early in disease, and second follow the response to triple therapy in plasma and lymphoid tissue in tandem. As is known for lymph nodes with more advanced disease, the germinal centers showed productively infected T cells, i.e., CD4+CD1a−CD68− cells labeling intensely for HIV-1 RNA after in situ hybridization. The unenlarged nodes also showed extensive HIV-1 RNA retention on a well-preserved, follicular dendritic cell (FDC) network, and the follicles were abnormal. There were numerous CD8+ cells, many expressing TIA-1 granule antigen. Also, in contrast to normal follicles, CD4+ T cell proliferation was active, with marked increases in the number of cycling, Ki-67+CD4+CD45R0+ cells. After 28 d and 3 mo of therapy, productively infected T cells decreased dramatically and often were not apparent. The labeling of the FDC network for viral RNA also decreased, but not for gag protein. We conclude that HIV-1 replicates and accumulates in lymphoid organs before damage of the immune system, that at this stage of disease de novo production of T cells occurs in the lymphoid tissue, and that the infection is sensitive to triple drug therapy in both plasma and lymph nodes.

The results from the HPTN 052 trial have increased the focus on use of antiretroviral therapy (ART) for prevention of HIV transmission; however, condom use also effectively prevents HIV transmission. Studies in heterosexual serodiscordant couples with viral suppression have so far only reported follow-up data for 330 couple-years when condoms were not being used. Data are even more limited for anal sex in men who have sex with men. Additional data on the effectiveness of ART as prevention when practicing condom-less sex is urgently needed.

Heterogenous immune reconstitution and de novo priming of HIV-specific T cells characterize allo-HSCT recovery in HIV-infected individuals.

Glycoprotein B (gB) is involved in cell to cell transmission of human Cytomegalovirus (HCMV) and may be a critical factor in tissue tropism and viral pathogenesis. We analyzed the distribution of the four known gB genotypes of HCMY in 99 HIV-positive patients. 29 patients had HCMV retinitis, and 70 patients had asymptomatic HCMV infection. DNA was isolated from blood, urine, and aqueous humor, and gB genotypes were determined by PCR and restriction analysis. Infections with gB type 1 were less frequent in patients with retinitis than in patients with asymptomatic HCMV infection (17% versus 37%; p = 0.05). Furthermore, the gB type was correlated with dissemination of infection. In patients with HCMV detected in only one compartment (blood or urine) the gB type 1 was found more frequently than in patients with HCMV detected in at least two compartments (p = 0.01). The data show that gB genotypes differ in their association with clinical disease, and indicate that the gB genotype may contribute to the course of HCMV infection.

No relevant conflicts of interest to declare.

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