Antiretroviral therapy response among HIV-2 infected patients: a systematic review

Efficacy and safety of three antiretroviral therapy regimens for treatment-naive African adults living with HIV-2 (FIT-2): a pilot, phase 2, non-comparative, open-label, randomised controlled trial

BACKGROUND

Due to the low number of individuals with HIV-2, no randomised trials of HIV-2 treatment have ever been done. We hypothesised that a non-comparative study describing the outcomes of several antiretroviral therapy (ART) regimens in parallel groups would improve understanding of how differences between HIV-1 and HIV-2 might lead to different therapeutic approaches.

METHODS

This pilot, phase 2, non-comparative, open-label, randomised controlled trial was done in Burkina Faso, Côte d'Ivoire, Senegal, and Togo. Adults with HIV-2 who were ART naive with CD4 counts of 200 cells per μL or greater were randomly assigned 1:1:1 to one of three treatment groups. A computer-generated sequentially numbered block randomisation list stratified by country was used for online allocation to the next available treatment group. In all groups, tenofovir disoproxil fumarate (henceforth tenofovir) was dosed at 245 mg once daily with either emtricitabine at 200 mg once daily or lamivudine at 300 mg once daily. The triple nucleoside reverse transcriptase inhibitor (NRTI) group received zidovudine at 250 mg twice daily. The ritonavir-boosted lopinavir group received lopinavir at 400 mg twice daily boosted with ritonavir at 100 mg twice daily. The raltegravir group received raltegravir at 400 mg twice daily. The primary outcome was the rate of treatment success at week 96, defined as an absence of serious morbidity event during follow-up, plasma HIV-2 RNA less than 50 copies per mL at week 96, and a substantial increase in CD4 cells between baseline and week 96. This trial is registered at ClinicalTrials.gov, NCT02150993, and is closed to new participants.

FINDINGS

Between Jan 26, 2016, and June 29, 2017, 210 participants were randomly assigned to treatment groups. Five participants died during the 96 weeks of follow-up (triple NRTI group, n=2; ritonavir-boosted lopinavir group, n=2; and raltegravir group, n=1), eight had a serious morbidity event (triple NRTI group, n=4; ritonavir-boosted lopinavir group, n=3; and raltegravir group, n=1), 17 had plasma HIV-2 RNA of 50 copies per mL or greater at least once (triple NRTI group, n=11; ritonavir-boosted lopinavir group, n=4; and raltegravir group, n=2), 32 (all in the triple NRTI group) switched to another ART regimen, and 18 permanently discontinued ART (triple NRTI group, n=5; ritonavir-boosted lopinavir group, n=7; and raltegravir group, n=6). The Data Safety Monitoring Board recommended premature termination of the triple NRTI regimen for safety reasons. The overall treatment success rate was 57% (95% CI 47-66) in the ritonavir-boosted lopinavir group and 59% (49-68) in the raltegravir group.

INTERPRETATION

The raltegravir and ritonavir-boosted lopinavir regimens were efficient and safe in adults with HIV-2. Both regimens could be compared in future phase 3 trials. The results of this pilot study suggest a trend towards better virological and immunological efficacy in the raltegravir-based regimen.

FUNDING

ANRS MIE.

Clinical Outcomes of Integrase Strand Transfer Inhibitors Containing Antiretroviral Therapy in HIV-2: A Narrative Review

The human immunodeficiency virus type 2 (HIV-2) is a particular subtype of HIV, which is endemic in West Africa and is characterized by a more indolent course than HIV-1. As people living with HIV-2 (PWH-2) are at risk for the development of acquired immunodeficiency syndrome and can transmit the virus, antiretroviral therapy is usually indicated. However, the optimal treatment of HIV-2 is unknown and historically the protease inhibitors (PIs) were a regular part of therapy. Nowadays, the use of integrase strand transfer inhibitors (INSTIs) in HIV-2 is increasing but the evidence supporting this approach is limited. In this narrative review, we outline the clinical data on the use of INSTI-containing antiretroviral therapy in HIV-2. We found that in the setting of treatment-naïve PWH-2, the use of INSTIs is successful, but also noted large heterogeneity in reported outcomes and that most cohorts are small with limited follow-up time. There is a lack of studies comparing the efficacy of INSTIs to other first-line options. For treatment-experienced PWH-2, the efficacy of INSTI is highly variable.

Human Immunodeficiency Virus Type 2: The Neglected Threat

West Africa has the highest prevalence of human immunodeficiency virus (HIV)-2 infection in the world, but a high number of cases has been recognized in Europe, India, and the United States. The virus is less transmissible than HIV-1, with sexual contacts being the most frequent route of acquisition. In the absence of specific antiretroviral therapy, most HIV-2 carriers will develop AIDS. Although, it requires more time than HIV-1 infection, CD4+ T cell decline occurs more slowly in HIV-2 than in HIV-1 patients. HIV-2 is resistant to non-nucleoside reverse transcriptase inhibitors (NNRTIs) and some protease inhibitors. Misdiagnosis of HIV-2 in patients mistakenly considered HIV-1-positive or in those with dual infections can cause treatment failures with undetectable HIV-1 RNA. In this era of global integration, clinicians must be aware of when to consider the diagnosis of HIV-2 infection and how to test for this virus. Although there is debate regarding when therapy should be initiated and which regimen should be chosen, recent trials have provided important information on treatment options for HIV-2 infection. In this review, we focus mainly on data available and on the insight they offer about molecular epidemiology, clinical presentation, antiretroviral therapy, and diagnostic tests of HIV-2 infection.

Effectiveness of dolutegravir-based antiretroviral treatment for HIV-2 infection: retrospective observational study from Western India

BACKGROUND

Data on the use of dolutegravir for treatment of HIV-2 infection are limited.

OBJECTIVES

To assess the effectiveness of dolutegravir in people living with HIV-2 (PLHIV-2).

METHODS

A retrospective chart review was performed in two clinics in Western India. PLHIV-2 initiated on dolutegravir-based regimens were included. Response to treatment in both treatment-naive (TN) and treatment-experienced (TE; substitution and not in the context of failure) was assessed by CD4 counts and HIV-2 viral load (VL) in a proportion of individuals. The primary objective was to assess immunological effectiveness (absence of a drop in absolute CD4 counts by more than 30% of baseline). Change in absolute CD4 counts was assessed by fitting a mixed-effects model.

RESULTS

Sixty-two PLHIV-2 treated with dolutegravir were included. The immunological effectiveness rates (95% CI) were 91.9% (82.4%-96.5%), 92% (81.1%-96.8%) and 91.6% (64.6%-98.5%) amongst all, TE and TN individuals, respectively. Median change in absolute CD4 counts at 6, 12 and 18 months were +29 cells/mm3, +101 cells/mm3 and +72 cells/mm3, respectively. The virological effectiveness rates (HIV-2 VL <100 copies/mL) (95% CI) for all, TE and TN individuals were 88.8% (74.6%-95%), 89.6% (73.6%-96.4%) and 85.7% (48.6%-97.4%), respectively. Three clinical events were documented: spinal tuberculosis, relapsed non-Hodgkin's lymphoma and herpes simplex virus retinitis. One individual reported self-limiting somnolence.

CONCLUSIONS

Dolutegravir was well tolerated and associated with immunological, virological and clinical effectiveness in both TN and TE PLHIV-2 in a large cohort from Western India. Dolutegravir-based ART is an excellent option for treatment of individuals with HIV-2 infection.

Human Immunodeficiency Virus-2 (HIV-2): A Summary of the Present Standard of Care and Treatment Options for Individuals Living with HIV-2 in Western Europe

Human immunodeficiency virus-2 (HIV-2) is endemic in some countries in West Africa. Due to the lower prevalence in industrialized countries, there is limited experience and knowledge on the management of individuals living with HIV-2 in Europe. Compared to HIV-1, there are differential characteristics of HIV-2 regarding diagnostic procedures, the clinical course, and, most importantly, antiretroviral therapy. We integrated the published literature on HIV-2 (studies and reports on epidemiology, diagnostics, the clinical course, and treatment), as well as expert experience in diagnosing and clinical care, to provide recommendations for a present standard of medical care of those living with HIV-2 in Western European countries, including an overview of strategies for diagnosis, monitoring, and treatment, with suggestions for effective drug combinations for first- and second-line treatments, post-exposure prophylaxis, and the prevention of mother-to-child transmission, as well as listings of mutations related to HIV-2 drug resistance and C-C motif chemokine receptor type 5 and C-X-C motif chemokine receptor type 4 coreceptor tropism.

Long-term Experience and Outcomes of Programmatic Antiretroviral Therapy for Human Immunodeficiency Virus Type 2 Infection in Senegal, West Africa

BACKGROUND

Programmatic treatment outcome data for people living with human immunodeficiency virus type 2 (HIV-2) in West Africa, where the virus is most prevalent, are scarce.

METHODS

Adults with HIV-2 initiating or receiving antiretroviral therapy (ART) through the Senegalese national AIDS program were invited to participate in this prospective, longitudinal observational cohort study. We analyzed HIV-2 viral loads, CD4 cell counts, antiretroviral drug resistance, loss to follow-up, and mortality. We also examined changes in treatment guidelines over time and assessed progress toward the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets for HIV-2.

RESULTS

We enrolled 291 participants at 2 sites for 926.0 person-years of follow-up over 13 years. Median follow-up time was 2.2 years per participant. There were 21 deaths reported (7.2%), and 117 individuals (40.2%) were lost to follow-up, including 43 (14.7%) who had an initial visit but never returned for follow-up. CD4 counts and HIV-2 viral suppression (< 50 copies/mL) at enrollment increased over calendar time. Over the study period, 76.7% of plasma viral loads for participants receiving ART were suppressed, and median CD4 gain was 84 cells/μL in participants' first 2 years on study. Since the UNAIDS 90-90-90 strategy was published, 88.1% of viral loads were suppressed. Fifteen percent of patients experienced virologic failure with no known resistance mutations, while 56% had evidence of multiclass drug resistance.

CONCLUSIONS

Participants in the Senegalese national AIDS program are initiating ART earlier in the course of disease, and more modern therapeutic regimens have improved outcomes among those receiving therapy. Despite these achievements, HIV-2 treatment remains suboptimal, and significant challenges to improving care remain.

The first case of HIV-2 in Scotland

HIV-1 infects an estimated 37 million people worldwide, while the rarer HIV-2 infects 1–2 million worldwide. HIV-2 is mainly restricted to West African countries. The majority of patients in Scotland are diagnosed with HIV-1, but in 2013 the West of Scotland Specialist Virology Centre (WoSSVC) diagnosed Scotland’s first HIV-2 positive case in a patient from Côte d’Ivoire. HIV-2 differs from HIV-1 in terms of structural viral proteins, viral transmissibility, prolonged period of latency, intrinsic resistance to certain antivirals and how to monitor the effectiveness of treatment. Over the course of 5 years the patient has required several changes in treatment due to both side effects and pill burden. This case highlights the complexity of HIV-2 patient management over time.

Clinical experience with integrase inhibitors in HIV-2-infected individuals in Spain

BACKGROUND

HIV-2 is a neglected virus despite estimates of 1-2 million people being infected worldwide. The virus is naturally resistant to some antiretrovirals used to treat HIV-1 and therapeutic options are limited for patients with HIV-2.

METHODS

In this retrospective observational study, we analysed all HIV-2-infected individuals treated with integrase strand transfer inhibitors (INSTIs) recorded in the Spanish HIV-2 cohort. Demographics, treatment modalities, laboratory values, quantitative HIV-2 RNA and CD4 counts as well as drug resistance were analysed.

RESULTS

From a total of 354 HIV-2-infected patients recruited by the Spanish HIV-2 cohort as of December 2017, INSTIs had been given to 44, in 18 as first-line therapy and in 26 after failing other antiretroviral regimens. After a median follow-up of 13 months of INSTI-based therapy, undetectable viraemia for HIV-2 was achieved in 89% of treatment-naive and in 65.4% of treatment-experienced patients. In parallel, CD4 gains were 82 and 126 cells/mm3, respectively. Treatment failure occurred in 15 patients, 2 being treatment-naive and 13 treatment-experienced. INSTI resistance changes were recognized in 12 patients: N155H (5), Q148H/R (3), Y143C/G (3) and R263K (1).

CONCLUSIONS

Combinations based on INSTIs are effective and safe treatment options for HIV-2-infected individuals. However, resistance mutations to INSTIs are selected frequently in failing patients, reducing the already limited treatment options.

Long-term immunological responses to treatment among HIV-2 patients in Côte d'Ivoire

BACKGROUND

Studies indicate that responses to HIV-2 treatment regimens are worse than responses to HIV-1 regimens during the first 12 months of treatment, but longer-term treatment responses are poorly described. We utilized data from Côte d'Ivoire's RETRO-CI laboratory to examine long-term responses to HIV-2 treatment.

METHODS

Adult (≥15 years) patients with baseline CD4 counts < 500 cells/μl that initiated treatment at one of two HIV treatment centers in Abidjan, Côte d'Ivoire between 1998 and 2004 were included in this retrospective cohort study. Patients were stratified by baseline CD4 counts and survival analyses were employed to examine the relationship between HIV type and time to achieving CD4 ≥ 500 cells/μl during follow up.

RESULTS

Among 3487 patients, median follow-up time was 4 years and 57% had documented ART regimens for > 75% of their recorded visits. Kaplan-Meier estimates for achievement of CD4 ≥ 500 cells/μl after 6 years of follow-up for patients in the lower CD4 strata (< 200 cells/μl) were 40% (HIV-1), 31% (HIV-dual), and 17% (HIV-2) (log-rank p < 0.001). Cox Regression indicated that HIV-1 was significantly associated with achievement of CD4 ≥ 500 cells/μl during follow-up, compared to HIV-2.

CONCLUSIONS

Sub-optimal responses to long-term HIV-2 treatment underscore the need for more research into improved and/or new treatment options for patients with HIV-2. In many West African countries, effective treatment of both HIV-1 and HIV-2 will be essential in the effort to reach epidemic control.

Human Immunodeficiency Virus Drug Resistance: 2018 Recommendations of the International Antiviral Society-USA Panel

Background

Contemporary antiretroviral therapies (ART) and management strategies have diminished both human immunodeficiency virus (HIV) treatment failure and the acquired resistance to drugs in resource-rich regions, but transmission of drug-resistant viruses has not similarly decreased. In low- and middle-income regions, ART roll-out has improved outcomes, but has resulted in increasing acquired and transmitted resistances. Our objective was to review resistance to ART drugs and methods to detect it, and to provide updated recommendations for testing and monitoring for drug resistance in HIV-infected individuals.

Methods

A volunteer panel of experts appointed by the International Antiviral (formerly AIDS) Society–USA reviewed relevant peer-reviewed data that were published or presented at scientific conferences. Recommendations were rated according to the strength of the recommendation and quality of the evidence, and reached by full panel consensus.

Results

Resistance testing remains a cornerstone of ART. It is recommended in newly-diagnosed individuals and in patients in whom ART has failed. Testing for transmitted integrase strand-transfer inhibitor resistance is currently not recommended, but this may change as more resistance emerges with widespread use. Sanger-based and next-generation sequencing approaches are each suited for genotypic testing. Testing for minority variants harboring drug resistance may only be considered if treatments depend on a first-generation nonnucleoside analogue reverse transcriptase inhibitor. Different HIV-1 subtypes do not need special considerations regarding resistance testing.

Conclusions

Testing for HIV drug resistance in drug-naive individuals and in patients in whom antiretroviral drugs are failing, and the appreciation of the role of testing, are crucial to the prevention and management of failure of ART.

Treatment outcome in dually HIV-1 and HIV-2 coinfected patients living in Spain

BACKGROUND

Whereas HIV-1 has spread globally, HIV-2 is mainly found in West Africa where dual HIV-1/HIV-2 coinfection is nowadays uncommon. Herein, we report the rate, main characteristics, and treatment outcomes of all dually infected patients living in Spain.

METHODS

We identified retrospectively all persons coinfected with HIV-1 recorded at the Spanish HIV-2 registry. Dual infection had been confirmed using PCR in plasma and/or cells, and/or using discriminatory serological tests.

RESULTS

From a total of 373 individuals with HIV-2 recorded at the Spanish registry, 34 (9.1%) were coinfected with HIV-1. Compared with HIV-2 monoinfected persons, dually infected patients were more often male (67.6%), presented with lower median CD4 cell counts (204 cells/μl), and had developed more frequently AIDS events (26.5%). Although 61.7% came from West Africa, 6 (17.6%) were native Spaniards. HIV-1 non-B subtypes were recognized in 75% of coinfected patients, being the most prevalent CRF02_AG. At baseline, 45% of dually infected patients had undetectable plasma HIV-2 RNA. After a median follow-up of 32 (13-48) months on antiretroviral therapy, dually infected patients achieved undetectable viremia in 85% for HIV-1, in 80% for HIV-2; and in 70% for both viruses. Median CD4 cell counts reached up to 418 cells/μl.

CONCLUSION

Roughly 9% of individuals with HIV-2 infection living in Spain are coinfected with HIV-1. Overall, 70% of dually infected patients achieved viral suppression for both viruses under antiretroviral therapy. Given the relatively large population of West Africans living in Spain and the continuous migration flow from HIV-2 endemic areas, HIV-1/HIV-2 coinfection should always be excluded at first diagnosis in all HIV-seroreactive persons.

First-line Raltegravir/Emtricitabine/Tenofovir Combination in Human Immunodeficiency Virus Type 2 (HIV-2) Infection: A Phase 2, Noncomparative Trial (ANRS 159 HIV-2)

Background

New options for first-line treatment of human immunodeficiency virus type 2 (HIV-2) infection are needed. We evaluated an integrase inhibitor (raltegravir)–containing regimen.

Methods

Antiretroviral therapy (ART)–naive adults with symptomatic infection by HIV-2 only, CD4 count <500 cells/μL or CD4 decrease >50 cells/μL/year over the past 3 years, or a confirmed plasma HIV-2 RNA (pVL) load ≥100 copies/mL were eligible for this noncomparative trial. The composite primary endpoint was survival at 48 weeks without any of the following: CD4 gain from baseline <100 cells/μL, confirmed pVL ≥40 copies/mL from week 24, raltegravir permanent discontinuation, or incident B or C event. HIV-2 ultrasensitive pVL (uspVL) and total DNA were assessed using in-house polymerase chain reaction (PCR) assays.

Results

Baseline median CD4 count of 30 enrolled individuals (67% women) was 436 cells/µL (interquartile range [IQR], 314–507 cells/µL); pVL was ≥40 copies/mL in 67% of them, uspVL was ≥5 copies/mL in 92%, and total DNA was >6 copies by PCR in 32%. At week 48, the composite endpoint of success was reached in 40% [95% confidence interval, 22.7%–59.4%]. Failure was mainly (50%) due to CD4 gain <100 cells/µL; uspVL was <5 copies/mL in 87% and total DNA >6 copies by PCR in 12% of participants. Median CD4 gain was 87 cells/µL (IQR, 38–213 cells/µL; n = 28). No serious adverse reactions were reported.

Conclusions

Raltegravir-containing ART is a safe option for first-line treatment of HIV-2 infection, yielding a comparable success rate to protease inhibitors.

Clinical Trials Registration

NCT 01605890.

A Trial of a Single-tablet Regimen of Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Disoproxil Fumarate for the Initial Treatment of Human Immunodeficiency Virus Type 2 Infection in a Resource-limited Setting: 48-Week Results From Senegal, West Africa

Background

There is an urgent need for safe and effective antiretroviral therapy (ART) for human immunodeficiency virus type 2 (HIV-2) infection. We undertook the first clinical trial of a single-tablet regimen containing elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (E/C/F/TDF) to assess its effectiveness in HIV-2-infected individuals in Senegal, West Africa.

Methods

HIV-2-infected, ART-naive adults with World Health Organization stage 3-4 disease or CD4 count <750 cells/μL were eligible for this 48-week, open-label trial. We analyzed HIV-2 viral loads (VL), CD4 counts, clinical and adverse events, mortality, and loss to follow-up.

Results

We enrolled 30 subjects who initiated E/C/F/TDF. Twenty-nine subjects completed 48 weeks of follow-up. The majority were female (80%). There were no deaths, no new AIDS-associated clinical events, and 1 loss to follow-up. The median baseline CD4 count was 408 (range, 34-747) cells/μL, which increased by a median 161 (range, 27-547) cells/μL at week 48. Twenty-five subjects had baseline HIV-2 VL of <50 copies/mL of plasma. In those with detectable HIV-2 VL, the median was 41 (range, 10-6135) copies/mL. Using a modified intent-to-treat analysis (US Food and Drug Administration Snapshot method), 28 of 30 (93.3%; 95% confidence interval, 77.9%-99.2%) had viral suppression at 48 weeks. The 1 subject with virologic failure had multidrug-resistant HIV-2 (reverse transcriptase mutation: K65R; integrase mutations: G140S and Q148R) detected at week 48. There were 8 grade 3-4 adverse events; none were deemed study related. Adherence and acceptability were good.

Conclusions

Our data suggest that E/C/F/TDF, a once-daily, single-tablet-regimen, is safe, effective, and well tolerated. Our findings support the use of integrase inhibitor-based regimens for HIV-2 treatment.

Clinical Trials Registration

NCT02180438.

90-90-90 for HIV-2? Ending the HIV-2 epidemic by enhancing care and clinical management of patients infected with HIV-2

Distinct from HIV-1 and often neglected in the global campaign to end the AIDS epidemic, HIV-2 presents unique and underappreciated challenges in diagnosis, clinical care, antiretroviral therapy (ART), and HIV programmatic management. Here, we review the epidemiology and natural history of HIV-2, diagnostics and algorithms for accurately diagnosing and differentiating HIV-2 from HIV-1, the unique features of HIV-2 ART and drug resistance, and the clinical care and management of patients infected with HIV-2 in both developed and resource-limited settings. Ultimately, further research is needed to address the gaps in our knowledge of HIV-2 infection, increased resources are needed to specifically target HIV-2 as part of the UNAIDS/WHO 90-90-90 campaign to end AIDS, and increased determination is needed to better advocate for inclusion of people living with HIV-2 in global HIV/AIDS initiatives.

CD4 cell count response to first-line combination ART in HIV-2+ patients compared with HIV-1+ patients: a multinational, multicohort European study

Background

CD4 cell recovery following first-line combination ART (cART) is poorer in HIV-2+ than in HIV-1+ patients. Only large comparisons may allow adjustments for demographic and pretreatment plasma viral load (pVL).

Methods

ART-naive HIV+ adults from two European multicohort collaborations, COHERE (HIV-1 alone) and ACHIeV2e (HIV-2 alone), were included, if they started first-line cART (without NNRTIs or fusion inhibitors) between 1997 and 2011. Patients without at least one CD4 cell count before start of cART, without a pretreatment pVL and with missing a priori-defined covariables were excluded. Evolution of CD4 cell count was studied using adjusted linear mixed models.

Results

We included 185 HIV-2+ and 30321 HIV-1+ patients with median age of 46 years (IQR 36-52) and 37 years (IQR 31-44), respectively. Median observed pretreatment CD4 cell counts/mm3 were 203 (95% CI 100-290) in HIV-2+ patients and 223 (95% CI 100-353) in HIV-1+ patients. Mean observed CD4 cell count changes from start of cART to 12 months were +105 (95% CI 77-134) in HIV-2+ patients and +202 (95% CI 199-205) in HIV-1+ patients, an observed difference of 97 cells/mm3 in 1 year. In adjusted analysis, the mean CD4 cell increase was overall 25 CD4 cells/mm3/year lower (95% CI 5-44; P = 0.0127) in HIV-2+ patients compared with HIV-1+ patients.

Conclusions

A poorer CD4 cell increase during first-line cART was observed in HIV-2+ patients, even after adjusting for pretreatment pVL and other potential confounders. Our results underline the need to identify more potent therapeutic regimens or strategies against HIV-2.

Antiretroviral treatment of HIV-2 infection

HIV-2 is a neglected virus despite estimates of 1–2 million people being infected worldwide. AIDS develops more slowly in HIV-2 than HIV-1. Outside endemic regions, HIV-2 is mostly found in immigrants from west Africa or their sex partners. There are four major caveats when treating HIV-2. First, some antiretrovirals are not or only partially active against HIV-2. Second, CD4 declines in HIV-2 occur slowly, but CD4 recovery is smaller with antiretroviral treatment. Third, both virological failure and rapid emergence of drug resistance occur more frequently in HIV-2 than HIV-1. Finally, misdiagnosis of HIV-2 in patients wrongly considered as infected with HIV-1 or in those dually infected may result in treatment failures with undetectable HIV-1 RNA. Integrase inhibitors, and especially dolutegravir, should be part of any preferred HIV-2 antiretroviral combination nowadays.

MK-8591 (4'-Ethynyl-2-Fluoro-2'-Deoxyadenosine) Exhibits Potent Activity against HIV-2 Isolates and Drug-Resistant HIV-2 Mutants in Culture

There is a pressing need to identify more effective antiretroviral drugs for HIV-2 treatment. Here, we show that the investigational compound MK-8591 (4'-ethynyl-2-fluoro-2'-deoxyadenosine [EFdA]) is highly active against group A and B isolates of HIV-2; 50% effective concentrations [EC₅₀] for HIV-2 were, on average, 4.8-fold lower than those observed for HIV-1. MK-8591 also retains potent activity against multinucleoside-resistant HIV-2 mutants (EC₅₀ ≤ 11 nM). These data suggest that MK-8591 may have antiviral activity in HIV-2-infected individuals.

The Immune Interaction between HIV-1 Infection and Mycobacterium tuberculosis

The modulation of tuberculosis (TB)-induced immunopathology caused by human immunodeficiency virus (HIV)-1 coinfection remains incompletely understood but underlies the change seen in the natural history, presentation, and prognosis of TB in such patients. The deleterious combination of these two pathogens has been dubbed a "deadly syndemic," with each favoring the replication of the other and thereby contributing to accelerated disease morbidity and mortality. HIV-1 is the best-recognized risk factor for the development of active TB and accounts for 13% of cases globally. The advent of combination antiretroviral therapy (ART) has considerably mitigated this risk. Rapid roll-out of ART globally and the recent recommendation by the World Health Organization (WHO) to initiate ART for everyone living with HIV at any CD4 cell count should lead to further reductions in HIV-1-associated TB incidence because susceptibility to TB is inversely proportional to CD4 count. However, it is important to note that even after successful ART, patients with HIV-1 are still at increased risk for TB. Indeed, in settings of high TB incidence, the occurrence of TB often remains the first presentation of, and thereby the entry into, HIV care. As advantageous as ART-induced immune recovery is, it may also give rise to immunopathology, especially in the lower-CD4-count strata in the form of the immune reconstitution inflammatory syndrome. TB-immune reconstitution inflammatory syndrome will continue to impact the HIV-TB syndemic.

HIV type 2 epidemic in Spain: challenges and missing opportunities

: HIV type 2 (HIV-2) is a neglected virus despite estimates of 1-2 million people infected worldwide. HIV-2 is less efficiently transmitted than HIV-1 by sex and from mother to child. Although AIDS may develop in HIV-2 carriers, it takes longer than in HIV-1-infected patients. In contrast with HIV-1 infection, there is no global pandemic caused by HIV-2, as the virus is largely confined to West Africa. In a less extent and due to socioeconomic ties and wars, HIV-2 is prevalent in Portugal and its former colonies in Brazil, India, Mozambique and Angola. Globally, HIV-2 infections are steadily declining over time. A total of 338 cases of HIV-2 infection had been reported at the Spanish HIV-2 registry until December 2016, of whom 63% were men. Overall 72% were sub-Saharan Africans, whereas 16% were native Spaniards. Dual HIV-1 and HIV-2 coinfection was found in 9% of patients. Heterosexual contact was the most likely route of HIV-2 acquisition in more than 90% of cases. Roughly one-third presented with CD4 cell counts less than 200 cells/μl and/or AIDS clinical events. Plasma HIV-2 RNA was undetectable at baseline in 40% of patients. To date, one-third of HIV-2 carriers have received antiretroviral therapy, using integrase inhibitors 32 individuals. New diagnoses of HIV-2 in Spain have remained stable since 2010 with an average of 15 cases yearly. Illegal immigration from Northwestern African borders accounts for over 75% of new HIV-2 diagnoses. Given the relatively large community of West Africans already living in Spain and the continuous flux of immigration from endemic regions, HIV-2 infection either alone or as coinfection with HIV-1 should be excluded once in all HIV-seroreactive persons, especially when showing atypical HIV serological profiles, immunovirological disconnect (CD4 cell count loss despite undetectable HIV-1 viremia) and/or high epidemiological risks (birth in or sex partners from endemic regions).

Insight into HIV-2 latency may disclose strategies for a cure for HIV-1 infection

HIV-1 and HIV-2 originate from two distinct zoonotic transmissions of simian immunodeficiency viruses from primate to human. Although both share similar modes of transmission and can result in the development of AIDS with similar clinical manifestations, HIV-2 infection is generally milder and less likely to progress to AIDS. HIV is currently incurable due to the presence of HIV provirus integrated into the host DNA of long-lived memory cells of the immune system without active replication. As such, the latent virus is immunologically inert and remains insensitive to the administered antiviral drugs targeting active viral replication steps. Recent evidence suggests that persistent HIV replication may occur in anatomical sanctuaries such as the lymphoid tissue due to low drug penetration. At present, different strategies are being evaluated either to completely eradicate the virus from the patient (sterilising cure) or to allow treatment interruption without viral rebound (functional cure). Because HIV-2 is naturally less pathogenic and displays a more latent phenotype than HIV-1, it may represent a valuable model that provides elementary information to cure HIV-1 infection. Insight into the viral and cellular determinants of HIV-2 replication may therefore pave the way for alternative strategies to eradicate HIV-1 or promote viral remission.

A humanized mouse model for HIV-2 infection and efficacy testing of a single-pill triple-drug combination anti-retroviral therapy

While HIV-2 is a causative agent for AIDS in addition to the better studied HIV-1, there is currently no suitable animal model for experimental studies for HIV-2 infection and evaluating promising drugs in vivo. Here we evaluated humanized mice for their susceptibility to HIV-2 infection and tested a single-pill three drug formulation of anti-retrovirals (NRTIs abacavir and lamivudine, integrase inhibitor dolutegravir) (trade name, Triumeq^R). Our results showed that hu-mice are susceptible to HIV-2 infection showing persistent viremia and CD4 T cell loss, key hallmarks of AIDS pathogenesis. Oral drug treatment led to full viral suppression and protection from CD4 T cell depletion. Cessation of therapy resulted in viral rebound and CD4 T cell loss. These proof-of-concept studies establish the utility of hu-mice for evaluating HIV-2 pathogenesis in more detail in the future, testing novel therapies and providing pre-clinical efficacy data of a three drug combination to treat HIV-2 infections.

Mortality and survival patterns of people living with HIV-2

PURPOSE OF REVIEW

People living with HIV-2 infected usually initiate antiretroviral therapy (ART) at an advanced period in the course of their infection after a long asymptomatic period characterized by high CD4 cell count and thus at a relatively advanced age. In the new international context of early and universal ART initiation, the aim was to review survival patterns among HIV-2 infected patients, either on ART or not.

RECENT FINDINGS

Very few reports were published on mortality in people living with HIV-2 during the last 5 years. People living with HIV-2 experience high mortality rates although lower than people living with HIV-1 before ART initiation. They seem to survive longer regardless of the conditions of ART use. Mortality is associated with late presentation, male sex, CD4 cell count less than 500 cell/μl, high plasma viral load, hemoglobin rate less than 8 g/dl and body mass index less than 18 kg/m.

SUMMARY

People living with HIV-2 initiate ART later than HIV-1 and HIV duals, resulting in higher disease progression and mortality rate. The clinical management of HIV-2 infected patients should now include early diagnosis and treatment initiation as per international guidelines. Further research needs to explore the 'what to start' question and document specific causes of death in people living with HIV-2 and enrolled in care in Africa.

Overview of HIV molecular epidemiology among people who inject drugs in Europe and Asia

HIV strains continuously evolve, tend to recombine, and new circulating variants are being discovered. Novel strains complicate efforts to develop a vaccine against HIV and may exhibit higher transmission efficiency and virulence, and elevated resistance to antiretroviral agents. The United Nations Joint Programme on HIV/AIDS (UNAIDS) set an ambitious goal to end HIV as a public health threat by 2030 through comprehensive strategies that include epidemiological input as the first step of the process. In this context, molecular epidemiology becomes invaluable as it captures trends in HIV evolution rates that shape epidemiological pictures across several geographical areas. This review briefly summarizes the molecular epidemiology of HIV among people who inject drugs (PWID) in Europe and Asia. Following high transmission rates of subtype G and CRF14_BG among PWID in Portugal and Spain, two European countries, Greece and Romania, experienced recent HIV outbreaks in PWID that consisted of multiple transmission clusters including subtypes B, A, F1, and recombinants CRF14_BG and CRF35_AD. The latter was first identified in Afghanistan. Russia, Ukraine, and other Former Soviet Union (FSU) states are still facing the devastating effects of epidemics in PWID produced by A_FSU (also known as IDU-A), B_FSU (known as IDU-B), and CRF03_AB. In Asia, CRF01_AE and subtype B (Western B and Thai B) travelled from PWID in Thailand to neighboring countries. Recombination hotspots in South China, Northern Myanmar, and Malaysia have been generating several intersubtype and inter-CRF recombinants (e.g. CRF07_BC, CRF08_BC, CRF33_01B etc.), increasing the complexity of HIV molecular patterns.

Inhibition Profiling of Retroviral Protease Inhibitors Using an HIV-2 Modular System

Retroviral protease inhibitors (PIs) are fundamental pillars in the treatment of HIV infection and acquired immunodeficiency syndrome (AIDS). Currently used PIs are designed against HIV-1, and their effect on HIV-2 is understudied. Using a modular HIV-2 protease cassette system, inhibition profiling assays were carried out for protease inhibitors both in enzymatic and cell culture assays. Moreover, the treatment-associated resistance mutations (I54M, L90M) were introduced into the modular system, and comparative inhibition assays were performed to determine their effect on the susceptibility of the protease. Our results indicate that darunavir, saquinavir, indinavir and lopinavir were very effective HIV-2 protease inhibitors, while tipranavir, nelfinavir and amprenavir showed a decreased efficacy. I54M, L90M double mutation resulted in a significant reduction in the susceptibility to most of the inhibitors with the exception of tipranavir. To our knowledge, this modular system constitutes a novel approach in the field of HIV-2 protease characterization and susceptibility testing.

Differential regulatory activities of viral protein X for anti-viral efficacy of nucleos(t)ide reverse transcriptase inhibitors in monocyte-derived macrophages and activated CD4(+) T cells

Vpx encoded by HIV-2 and SIVsm enhances retroviral reverse transcription in macrophages in vitro by mediating the degradation of the host SAMHD1 protein that hydrolyzes dNTPs and by elevating cellular dNTP levels. Here we employed RT-SHIV constructs (SIV encoding HIV-1 RT) to investigate the contribution of Vpx to the potency of NRTIs, which compete against dNTPs, in monocyte-derived macrophages (MDMs) and activated CD4(+) T cells. Relative to HIV-1, both SIV and RT-SHIV exhibited reduced sensitivities to AZT, 3TC and TDF in MDMs but not in activated CD4(+) T cells. However, when SIV and RT-SHIV constructs not coding for Vpx were utilized, we observed greater sensitivities to all NRTIs tested using activated CD4(+) T cells relative to the Vpx-coding counterparts. This latter phenomenon was observed for AZT only when using MDMs. Our data suggest that Vpx in RT-SHIVs may underestimate the antiviral efficacy of NRTIs in a cell type dependent manner.

The Nucleoside Analog BMS-986001 Shows Greater In Vitro Activity against HIV-2 than against HIV-1

Treatment options for individuals infected with human immunodeficiency virus type 2 (HIV-2) are restricted by the intrinsic resistance of the virus to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and the reduced susceptibility of HIV-2 to several protease inhibitors (PIs) used in antiretroviral therapy (ART). In an effort to identify new antiretrovirals for HIV-2 treatment, we evaluated the in vitro activity of the investigational nucleoside analog BMS-986001 (2',3'-didehydro-3'-deoxy-4'-ethynylthymidine; also known as censavudine, festinavir, OBP-601, 4'-ethynyl stavudine, or 4'-ethynyl-d4T). In single-cycle assays, BMS-986001 inhibited HIV-2 isolates from treatment-naive individuals, with 50% effective concentrations (EC50s) ranging from 30 to 81 nM. In contrast, EC50s for group M and O isolates of HIV-1 ranged from 450 to 890 nM. Across all isolates tested, the average EC50 for HIV-2 was 9.5-fold lower than that for HIV-1 (64 ± 18 nM versus 610 ± 200 nM, respectively; mean ± standard deviation). BMS-986001 also exhibited full activity against HIV-2 variants whose genomes encoded the single amino acid changes K65R and Q151M in reverse transcriptase, whereas the M184V mutant was 15-fold more resistant to the drug than the parental HIV-2ROD9 strain. Taken together, our findings show that BMS-986001 is an effective inhibitor of HIV-2 replication. To our knowledge, BMS-986001 is the first nucleoside analog that, when tested against a diverse collection of HIV-1 and HIV-2 isolates, exhibits more potent activity against HIV-2 than against HIV-1 in culture.

Plasma HIV-2 RNA According to CD4 Count Strata among HIV-2-Infected Adults in the IeDEA West Africa Collaboration

Background

Plasma HIV-1 RNA monitoring is one of the standard tests for the management of HIV-1 infection. While HIV-1 RNA can be quantified using several commercial tests, no test has been commercialized for HIV-2 RNA quantification. We studied the relationship between plasma HIV-2 viral load (VL) and CD4 count in West African patients who were either receiving antiretroviral therapy (ART) or treatment-naïve.

Method

A cross sectional survey was conducted among HIV-2-infected individuals followed in three countries in West Africa from March to December 2012. All HIV-2 infected-patients who attended one of the participating clinics were proposed a plasma HIV-2 viral load measurement. HIV-2 RNA was quantified using the new ultrasensitive in-house real-time PCR assay with a detection threshold of 10 copies/ mL (cps/mL).

Results

A total of 351 HIV-2-infected individuals participated in this study, of whom 131 (37.3%) were treatment naïve and 220 (62.7%) had initiated ART. Among treatment-naïve patients, 60 (46.5%) had undetectable plasma HIV-2 viral load (<10 cps/mL), it was detectable between 10-100 cps/mL in 35.8%, between 100-1000 cps/mL in 11.7% and >1000 cps/mL in 6.0% of the patients. Most of the treatment-naïve patients (70.2%) had CD4-T cell count ≥500 cells/mm³ and 43 (46.7%) of these patients had a detectable VL (≥10 cps/mL). Among the 220 patients receiving ART, the median CD4-T cell count rose from 231 to 393 cells/mm³ (IQR [259-561]) after a median follow-up duration of 38 months and 145 (66.0%) patients had CD4-T cell count ≤ 500 cells/mm³ with a median viral load of 10 cps/mL (IQR [10-33]). Seventy five (34.0%) patients had CD4-T cell count ≥ 500 cells/mm³, among them 14 (18.7%) had a VL between 10-100 cps/mL and 2 (2.6%) had VL >100 cps/mL.

Conclusion

This study suggests that the combination of CD4-T cell count and ultrasensitive HIV-2 viral load quantification with a threshold of 10 cps/mL, could improve ART initiation among treatment naïve HIV-2-infected patients and the monitoring of ART response among patients receiving treatment.

Infection with human retroviruses other than HIV-1: HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4

HIV-1 is the most prevalent retrovirus, with over 30 million people infected worldwide. Nevertheless, infection caused by other human retroviruses like HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4 is gaining importance. Initially confined to specific geographical areas, HIV-2, HTLV-1 and HTLV-2 are becoming a major concern in non-endemic countries due to international migration flows. Clinical manifestations of retroviruses range from asymptomatic carriers to life-threatening conditions, such as AIDS in HIV-2 infection or adult T-cell lymphoma/leukemia or tropical spastic paraparesis in HTLV-1 infection. HIV-2 is naturally resistant to some antiretrovirals frequently used to treat HIV-1 infection, but it does have effective antiretroviral therapy options. Unfortunately, HTLV still has limited therapeutic options. In this article, we will review the epidemiological, clinical, diagnostic, pathogenic and therapeutic aspects of infections caused by these human retroviruses.

[GESIDA/National AIDS Plan: Consensus document on antiretroviral therapy in adults infected by the human immunodeficiency virus (Updated January 2015)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines and recommendations for HIV-1 infected adult patients.

METHODS

To formulate these recommendations, a panel composed of members of the AIDS Study Group and the AIDS National Plan (GeSIDA/Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, and cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations, and the evidence that supports them, are based on modified criteria of the Infectious Diseases Society of America.

RESULTS

In this update, cART is recommended for all patients infected by type 1 human immunodeficiency virus (HIV-1). The strength and level of the recommendation depends on the CD4+T-lymphocyte count, the presence of opportunistic diseases or comorbid conditions, age, and prevention of transmission of HIV. The objective of cART is to achieve an undetectable plasma viral load. Initial cART should always comprise a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors, and a third drug from a different family. Three out of the ten recommended regimes are regarded as preferential (all of them with an integrase inhibitor as the third drug), and the other seven (based on a non-nucleoside reverse transcriptase inhibitor, a ritonavir-boosted protease inhibitor, or an integrase inhibitor) as alternatives. This update presents the causes and criteria for switching cART in patients with undetectable plasma viral load, and in cases of virological failure where rescue cART should comprise 3 (or at least 2) drugs that are fully active against the virus. An update is also provided for the specific criteria for cART in special situations (acute infection, HIV-2 infection, and pregnancy) and with comorbid conditions (tuberculosis or other opportunistic infections, kidney disease, liver disease, and cancer).

CONCLUSIONS

These new guidelines update previous recommendations related to cART (when to begin and what drugs should be used), how to monitor and what to do in case of viral failure or drug adverse reactions. cART specific criteria in comorbid patients and special situations are equally updated.