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

Salvage Therapy Including Foscarnet and Ibalizumab for Multidrug-Resistant Human Immunodeficiency Virus Type 2 Infection

We evaluated Ibalizumab (IBA)-containing standardized optimized salvage regimen (with or without a 4-week foscarnet induction) in individuals harboring multidrug-resistant human immunodeficiency virus type 2 (HIV-2). Nine were included; 2 achieved virological suppression after foscarnet induction with a sustained suppression at Week 24 after IBA initiation, and an additional individual at Week 24 after Ibalizumab initiation.

Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds

Currently, it is estimated that 1-2 million people worldwide are infected with HIV-2, accounting for 3-5% of the global burden of HIV. The course of HIV-2 infection is longer compared to HIV-1 infection, but without effective antiretroviral therapy (ART), a substantial proportion of infected patients will progress to AIDS and die. Antiretroviral drugs in clinical use were designed for HIV-1 and, unfortunately, some do not work as well, or do not work at all, for HIV-2. This is the case for non-nucleoside reverse transcriptase inhibitors (NNRTIs), the fusion inhibitor enfuvirtide (T-20), most protease inhibitors (PIs), the attachment inhibitor fostemsavir and most broadly neutralizing antibodies. Integrase inhibitors work well against HIV-2 and are included in first-line therapeutic regimens for HIV-2-infected patients. However, rapid emergence of drug resistance and cross-resistance within each drug class dramatically reduces second-line treatment options. New drugs are needed to treat infection with drug-resistant isolates. Here, we review the therapeutic armamentarium available to treat HIV-2-infected patients, as well as promising drugs in development. We also review HIV-2 drug resistance mutations and resistance pathways that develop in HIV-2-infected patients under treatment.

The HIV care continuum of Guinea-Bissau; Progress towards the UNAIDS 90-90-90 targets for HIV-1 and HIV-2

OBJECTIVE

In the 2020 UNAIDS HIV treatment goals, 90% of people living with HIV (PLHIV) should be diagnosed, 90% of these should receive antiretroviral treatment (ART) and 90% of these should be virally suppressed. We aimed to evaluate whether Guinea-Bissau fulfills the 2020 treatment goals for both for HIV-1 and HIV-2.

DESIGN

By combining data from a general population survey, treatment records from HIV clinics across Guinea-Bissau and a biobank from patients attending the largest HIV clinics in Bissau, we estimated each column of the 90-90-90 cascade.

METHOD

2601 participated in the survey and were used to estimate the proportion of PLHIV who knew their HIV status and the proportion of PLHIV on ART. Answers given in the survey was verified with treatment records from HIV clinics. We measured viral load from biobank materials from HIV patients and estimated the proportion of virally suppressed PLHIV.

RESULT

19.1% of PLHIV indicated to be aware of their HIV status. Of these, 48.5% received ART, and 76.4% of these were virally suppressed. For HIV-1 and HIV-1/2 the results were 21.2%, 40.9% and 75.1%. For HIV-2 the results were 15.9%, 63.6% and 80.7%. 26.9% of all HIV-1 infected in the survey were virologically suppressed, indicating that a much higher number of HIV-1 infected were aware of their status and on treatment.

CONCLUSION

Guinea-Bissau lags severely behind both the global and regional progress. Improvement in both testing and treating HIV is necessary to improve the quality of care.

High Instantaneous Inhibitory Potential of Bictegravir and the New Spiro-β-Lactam BSS-730A for HIV-2 Isolates from RAL-Naïve and RAL-Failing Patients

Integrase inhibitors (INIs) are an important class of drugs for treating HIV-2 infection, given the limited number of drugs active against this virus. While the clinical efficacy of raltegravir and dolutegravir is well established, the clinical efficacy of bictegravir for treating HIV-2 infected patients has not been determined. Little information is available regarding the activity of bictegravir against HIV-2 isolates from patients failing raltegravir-based therapy. In this study, we examined the phenotypic and matched genotypic susceptibility of HIV-2 primary isolates from raltegravir-naïve and raltegravir-failing patients to raltegravir, dolutegravir, and bictegravir, and to the new spiro-β-lactam BSS-730A. The instantaneous inhibitory potential (IIP) was calculated to help predict the clinical activity of bictegravir and BSS-730A. Isolates from raltegravir-naïve patients were highly sensitive to all INIs and BSS-730A. Combined integrase mutations E92A and Q148K conferred high-level resistance to raltegravir, and E92Q and T97A conferred resistance to raltegravir and dolutegravir. The antiviral activity of bictegravir and BSS-730A was not affected by these mutations. BSS-730A displayed strong antiviral synergism with raltegravir. Mean IIP values at Cmax were similar for all INIs and were not significantly affected by resistance mutations. IIP values were significantly higher for BSS-730A than for INIs. The high IIP values of bictegravir and BSS-730A for raltegravir-naïve and raltegravir-resistant HIV-2 isolates highlight their potential value for treating HIV-2 infection. Overall, the results are consistent with the high clinical efficacy of raltegravir and dolutegravir for HIV-2 infection and suggest a promising clinical profile for bictegravir and BSS-730A.

Long-term HIV treatment outcomes and associated factors in sub-Saharan Africa: multi-country longitudinal cohort analysis

OBJECTIVE

In a multicountry prospective cohort of persons with HIV from six countries between 2007 and 2015, we evaluated long-term outcomes of first-line non-nucleoside reverse-transcriptase inhibitor-based antiretroviral therapy (ART), and risk factors for loss-to-follow-up, mortality, virological failure, and incomplete CD4+ T-cell recovery.

METHODS

We calculated cumulative incidence of lost-to-follow-up, death, virological failure (VL ≥ 1000 cps/ml) and incomplete CD4+ T-cell recovery (<500 cells/μl) at successive years, using Kaplan-Meier and Cox regression.

RESULTS

Of 2735 participants, 58.0% were female, median age was 37 (interquartile range [IQR] 32-43) years, and median pre-ART CD4+ T-cell count was 135 (IQR 63-205)/μl. Total follow-up time was 7208 person-years (median 24.3 months, IQR 18.7-58.3). Deaths by any cause and loss to follow-up occurred mostly during the first year of ART (84%, 201/240 and 56%, 199/353, respectively). During their first 6 years of ART, 71% (95% confidence interval [CI] 69.0-73.7) were retained on first-line, and among those 90-93% sustained viral suppression (<1000 cps/ml); CD4+ T-cell recovery was incomplete in 60% (220/363) of participants. The risk factors associated with poor outcomes during long-term ART were: for loss-to-follow-up, recent VL ≥1000 cps/ml, recent CD4+ T-cell count ≤50 cells/μl, age <30 years, being underweight; for mortality, recent CD4+ T-cell count ≤50 cells/μl; and, for virological failure, age <40 years, recent CD4+ T-cell count ≤200 cells/μl, poor adherence, male sex, and low-level viremia.

CONCLUSION

To achieve long-term ART success towards the UNAIDS targets, early ART initiation is crucial, coupled with careful monitoring and retention support, particularly in the first year of ART. Male and youth-centred care delivery models are needed to improve outcomes for those vulnerable groups.

Novel assays to investigate the mechanisms of latent infection with HIV-2

Although there have been great advancements in the field of HIV treatment and prevention, there is no cure. There are two types of HIV: HIV-1 and HIV-2. In addition to genetic differences between the two types of HIV, HIV-2 infection causes a slower disease progression, and the rate of new HIV-2 infections has dramatically decreased since 2003. Like HIV-1, HIV-2 is capable of establishing latent infection in CD4+ T cells, thereby allowing the virus to evade viral cytopathic effects and detection by the immune system. The mechanisms underlying HIV latency are not fully understood, rendering this a significant barrier to development of a cure. Using RT-ddPCR, we previously demonstrated that latent infection with HIV-1 may be due to blocks to HIV transcriptional elongation, distal transcription/polyadenylation, and multiple splicing. In this study, we describe the development of seven highly-specific RT-ddPCR assays for HIV-2 that can be applied to the study of HIV-2 infections and latency. We designed and validated seven assays targeting different HIV-2 RNA regions along the genome that can be used to measure the degree of progression through different blocks to HIV-2 transcription and splicing. Given that HIV-2 is vastly understudied relative to HIV-1 and that it can be considered a model of a less virulent infection, application of these assays to studies of HIV-2 latency may inform new therapies for HIV-2, HIV-1, and other retroviruses.

Ibalizumab shows in vitro activity against group A and group B HIV-2 clinical isolates

OBJECTIVE

Treatment of multi-drug resistant HIV-2 is an emerging issue, due to the rapid selection of mutations at time of virological failure and the low number of antiretrovirals active on HIV-2. The aim of this study was to determine the susceptibility of HIV-2 primary isolates to ibalizumab, a long-acting monoclonal antibody that binds to CD4, that is approved for the treatment of MDR HIV-1.

METHODS

In vitro phenotypic susceptibility of 16 HIV-2 primary isolates was measured using a modified version of the ANRS peripheral blood mononuclear cells (PBMC) assay. Susceptibility to ibalizumab was assessed through 50% inhibitory concentrations and maximum percent inhibitions (MPI), and gp105 was sequenced to look for determinants of reduced susceptibility.

RESULTS

Ibalizumab inhibited viral replication of all 16 isolates, with a median IC50 value of 0.027 μg/mL (range = 0.001-0.506 μg/mL), and a median MPI of 93%. Although two isolates presented higher IC50 (above 0.1 μg/mL), they did not exhibit a loss of potential N-linked glycosylation sites in V5 loop, as reported in HIV-1 strains with reduced susceptibility. However, both presented shorter V1 and V2 loops than the HIV-2 reference strain.

CONCLUSIONS

Ibalizumab inhibits HIV-2 replication, with IC50 and MPI in the range of those reported for HIV-1. These in vitro data support the use of ibalizumab in patients with MDR HIV-2, in combination with an optimized background regimen.

Resource and infrastructure challenges on the RESIST-2 Trial: an implementation study of drug resistance genotype-based algorithmic ART switches in HIV-2-infected adults in Senegal

BACKGROUND

Second-line treatment of HIV-2 in resource-limited settings (RLS) is complicated by a lack of controlled trial data, limited availability of HIV-2-active antiretroviral drugs, and inadequate access to drug resistance testing. We conducted an implementation trial of a dried blood spot- (DBS) based, drug resistance genotype-informed antiretroviral therapy (ART) switching algorithm for HIV-2-infected patients in Senegal.

METHODS

HIV-2-infected adults initiating or receiving ART through the Senegalese national AIDS program were invited to participate in this single-arm trial. DBS from participants with virologic failure (defined as viral load (VL) > 250 copies/mL after > 6 months on the current ART regimen) were shipped to Seattle for genotypic drug resistance testing. Participants with evidence of drug resistance in protease or reverse transcriptase were switched to new regimens according to a pre-specified algorithm. Participant clinical and immuno-virologic outcomes were assessed, as were implementation challenges.

RESULTS

We enrolled 152 participants. Ten were initiating ART. The remainder were ART-experienced, with 91.0% virologically suppressed (< 50 copies/mL). Problems with viral load testing capability resulted in obtaining VL results for only 227 of 613 (37.0%) participant-visits. Six of 115 participants (5.2%) with VL available after > 6 months on current ART regimen experienced virologic failure, with per-protocol genotypic testing attempted. One additional test was performed for a participant with a VL of 222 copies/mL. Genotypes from three participants showed no evidence of major drug resistance mutations, two showed nucleoside reverse transcriptase inhibitor (NRTI) resistance, one showed both NRTI and protease inhibitor resistance, and one test failed. No integrase inhibitor resistance was observed. Five of six successfully-tested participants switched to the correct regimen or received additional adherence counseling according to the algorithm; the sixth was lost to follow-up. Follow-up VL testing was available for two participants; both of these were virally suppressed (< 10 copies/mL). The trial was terminated early due to the COVID-19 pandemic (which prevented further VL and genotypic testing), planned rollout of dolutegravir-based 1st-line ART, and funding.

CONCLUSIONS

The RESIST-2 trial demonstrated that a DBS-based genotypic test can be used to help inform second-line ART decisions as part of a programmatic algorithm in RLS, albeit with significant implementation challenges.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03394196 . Registered on January 9, 2018.

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.

Distribution characteristics of drug resistance mutations of HIV CRF01_AE, CRF07_BC and CRF08_BC from patients under ART in Ganzhou, China

BACKGROUND

Drug resistance mutation (DRM)-associated virological failure has become a critical issue for ART and the elimination of HIV.

OBJECTIVES

To investigate the distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC, the predominant subtypes in China.

METHODS

Patients receiving ART up to 31 August 2020 in Ganzhou in China were recruited. Full-length sequences of the HIV pol gene were amplified from patients with virological failure. DRMs and antiretroviral susceptibility were explored using the Stanford University HIV Drug Resistance Database HIVdb Program.

RESULTS

Overall, 279 of 2204 patients under ART were found to have virological failure. Nine HIV subtypes were identified among 211 sequences that were amplified successfully and CRF08_BC (37.0%), CRF01_AE (26.1%) and CRF07_BC (25.6%) were the most prevalent, with mutation frequencies of 44.9% (35/78), 52.7% (29/55) and 35.2% (19/54), respectively. The most common DRMs of these three subtypes were K103N and M184V, while the mutation frequencies of M41L, D67N, K70R, K101E, V106M, Y181C, K219E, H221Y and N348I were obviously different among subtypes. The resistance levels and frequencies for antiretroviral drugs for these three subtypes were similar and resistances to nevirapine, efavirenz, lamivudine and emtricitabine were the most frequently observed. Compared with CRF01_AE and CRF07_BC, CRF08_BC had higher proportions of DRMs for NRTIs and lower frequencies of resistance to NRTIs and NNRTIs.

CONCLUSIONS

The distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC were inconsistent and should be considered when selecting antiretroviral strategies, developing new drugs and controlling HIV strains containing DRMs.

HIV-2 Drug Resistance Genotyping from Dried Blood Spots

The treatment of HIV-2 in resource-limited settings (RLS) is complicated by the limited availability of HIV-2-active antiretroviral drugs and inadequate access to HIV-2 viral load and drug resistance testing. Dried blood spots (DBS)-based drug resistance testing, widely studied for HIV-1, has not been reported for HIV-2 and could present an opportunity to improve care for HIV-2-infected individuals. We selected 150 DBS specimens from ongoing studies of antiretroviral therapy (ART) for HIV-2 infection in Senegal and subjected them to genotypic drug resistance testing. Total nucleic acid was extracted from DBS, reverse transcribed, PCR amplified, and analyzed by population-based Sanger sequencing, and major drug resistance-associated mutations (RAM) were identified. Parallel samples from plasma and peripheral blood mononuclear cells (PBMC) were also genotyped. We obtained 58 protease/reverse transcriptase genotypes. Plasma viral load was significantly correlated with genotyping success (P < 0.001); DBS samples with corresponding plasma viral load >250 copies/ml had a success rate of 86.8%. In paired DBS-plasma genotypes, 83.8% of RAM found in plasma were also found in DBS, and replicate DBS genotyping revealed that a single test detected 86.7% of known RAM. These findings demonstrate that DBS-based genotypic drug resistance testing for HIV-2 is feasible and can be deployed in RLS with limited infrastructure.