Prevalence of people living with multidrug-resistant HIV and limited treatment options in Spain.

OBJECTIVES: Our aim was to determine the prevalence and characteristics of people with HIV on antiretroviral therapy (ART) with multidrug resistance (MDR; confirmed resistance to three or more [or resistance to two or more plus contraindication to one or more] core ART classes) and limited treatment options (LTOs) in Spain. METHODS: This was an observational, retrospective, multicentre, cross-sectional chart review study undertaken in five reference Spanish centres. Participants were people with HIV on ART with MDR and LTOs (detectable viral load [HIV-RNA >200 copies/mL], treatment-limiting drug-drug interaction [DDI], or intolerance precluding the use of one or more ART classes). Prevalence, demographic/clinical characteristics, and treatment options were assessed. Logistic regression analyses were used to identify MDR-associated variables. RESULTS: Of 14 955 screened people with HIV, 69 (0.46%) presented with MDR and 23 (0.15%) had LTOs. The population analysed was 73.9% male with a median age of 54.0 years; the median time since HIV diagnosis was 26.5 years, and median CD4+ cell count was 511.0 cells/µL. The only factor significantly associated with MDR (univariate analysis) was CD4+ cell count. Injection drug use was the most common transmission route. Comorbidities (mainly endocrine and cardiovascular disorders; 34.8% affecting HIV management) and concomitant treatments were frequent. No recent opportunistic infections were reported. Patients had been exposed to the following ART: nucleoside analogue reverse transcriptase inhibitors (100%), protease inhibitors (95.6%), non-nucleoside analogue reverse transcriptase inhibitors (87.0%), and integrase strand transfer inhibitors (82.6%). The available fully active drugs were dolutegravir (39.1%), bictegravir (30.4%), and raltegravir (21.7%). CONCLUSIONS: The prevalence of people with HIV with MDR and LTOs in Spain is very low, with approximately half of those studied not exhibiting virological suppression. Low CD4+ cell counts were associated with MDR. These findings may help address the impact and treatment needs of these patients and prevent clinical progression and transmission of MDR HIV.

Difficult-to-treat HIV in Sweden: a cross-sectional study.

BACKGROUND: Our aim was to examine the prevalence and characteristics of difficult-to-treat HIV in the current Swedish HIV cohort and to compare treatment outcomes between people with difficult and non-difficult-to-treat HIV. METHODS: In this cross-sectional analysis of the Swedish HIV cohort, we identified all people with HIV currently in active care in 2023 from the national register InfCareHIV. We defined five categories of difficult-to-treat HIV: 1) advanced resistance, 2) four-drug regimen, 3) salvage therapy, 4) virologic failure within the past 12 months, and 5) ≥ 2 regimen switches following virologic failure since 2008. People classified as having difficult-to-treat HIV were compared with non-difficult for background characteristics as well as treatment outcomes (viral suppression and self-reported physical and psychological health). RESULTS: Nine percent of the Swedish HIV cohort in 2023 (n = 8531) met at least one criterion for difficult-to-treat HIV. Most of them had ≥ 2 regimen switches (6%), and the other categories of difficult-to-treat HIV were rare (1-2% of the entire cohort). Compared with non-difficult, people with difficult-to-treat HIV were older, had an earlier first year of positive HIV test and lower CD4 counts, and were more often female. The viral suppression rate among people with difficult-to-treat HIV was 84% compared with 95% for non-difficult (p = 0.001). People with difficult-to-treat HIV reported worse physical (but not psychological) health, and this remained statistically significant after adjustment for age, sex, and transmission group. CONCLUSIONS: Although 9% of the HIV cohort in Sweden in 2023 were classified as having difficult-to-treat HIV, a large proportion of these were virally suppressed, and challenges such as advanced resistance and need for salvage therapy are rare in the current Swedish cohort.

Genetically edited CD34+ cells derived from human iPS cells in vivo but not in vitro engraft and differentiate into HIV-resistant cells.

Genetic editing of induced pluripotent stem (iPS) cells represents a promising avenue for an HIV cure. However, certain challenges remain before bringing this approach to the clinic. Among them, in vivo engraftment of cells genetically edited in vitro needs to be achieved. In this study, CD34+ cells derived in vitro from iPS cells genetically modified to carry the CCR5Δ32 mutant alleles did not engraft in humanized immunodeficient mice. However, the CD34+ cells isolated from teratomas generated in vivo from these genetically edited iPS cells engrafted in all experiments. These CD34+ cells also gave rise to peripheral blood mononuclear cells in the mice that, when inoculated with HIV in cell culture, were resistant to HIV R5-tropic isolates. This study indicates that teratomas can provide an environment that can help evaluate the engraftment potential of CD34+ cells derived from the genetically modified iPS cells in vitro. The results further confirm the possibility of using genetically engineered iPS cells to derive engraftable hematopoietic stem cells resistant to HIV as an approach toward an HIV cure.

Bictegravir/emtricitabine/tenofovir alafenamide in patients with genotypic NRTI resistance.

BACKGROUND: Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is approved for treatment of HIV without known resistance to its components. Several studies have demonstrated efficacy of B/F/TAF in patients with nucleoside reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs), mainly identified by proviral DNA testing, but data on the efficacy of B/F/TAF in patients with NRTI RAMs identified in viraemic plasma are limited. METHODS: We used a retrospective analysis of patients receiving B/F/TAF identified by searching electronic health records with eligibility confirmed by review of individual patient records. Patients included were ≥ 18 years, had 2019 International Antiviral Socitey-USA (IAS-USA) major RAMs affecting NRTIs detected in viraemic plasma prior to starting B/F/TAF and one or more HIV viral load (VL) after starting B/F/TAF. RESULTS: In all, 50 patients met the study criteria: mean age of 54 years, mean proximal CD4 count of 609 cells/µL, 64% male. A total of 46 were virologically suppressed (< 200 copies/mL) when B/F/TAF was initiated, two were treatment-naïve, one stopped prior antiretroviral therapy (ART) and one had a VL of 961 HIV-1 RNA copies/mL on ART. Twenty-nine had one NRTI RAM (24 were M184V/I), nine had two NRTI RAMs, three had three NRTI RAMs, four had four NRTI RAMs, two had five NRTI RAMs, one had six NRTI RAMs, one had seven RAMs and one had eight NRTI RAMs. At the last VL on B/F/TAF, a mean of 18.6 months after starting B/F/TAF, 49 out of 50 had VL < 100 copies/mL and one had a VL of 208 copies/mL at 11 months but only filled 5 months of B/F/TAF. CONCLUSIONS: B/F/TAF was effective in maintaining HIV VL suppression in patients with previously documented NRTI RAMs without integrase resistance.

Tenofovir diphosphate in dried blood spots and HIV-1 resistance in South Africa.

BACKGROUND: Suboptimal antiretroviral (ART) adherence can lead to virologic failure with consequent HIV-1 resistance. Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is a powerful biomarker of cumulative adherence, predictive of future viremia. It has been associated with resistance in Persons With HIV (PWH) in South Africa and the US. We explored the relationship of TFV-DP concentrations with antiretroviral drug resistance at the time of treatment failure in SA. METHODS: Adult PWH from health clinics in Cape Town, South Africa on efavirenz-based first-line ART containing tenofovir disoproxil fumarate (TDF) with an undetectable (< 50 copies/mL) HIV-1 viral load (VL) were prospectively enrolled in an observational cohort for 12 months. Monthly study visits included blood collection for HIV-1 VL and DBS for TFV-DP. The first confirmed viral breakthrough (VB) > 400 copies/mL triggered HIV-1 genotyping at the subsequent visit. An electronic adherence (EA) device monitored ART adherence in real-time, estimated as a percent for the 30-days prior to VB. Wilcoxon rank sum test was used to compare median [IQR] TFV-DP by genotype outcome. RESULTS: Of 250 individuals, (n = 195, 78% women), 21 experienced VB, with a median of 5 [4;7] months on study, and a median EA of 33.3 [13.3;53.3]%. Demographic characteristics between those with and without VB were similar. Median VL at VB was 4.0 [3.2;4.5] log copies/mL. TFV-DP concentrations trended down towards the VB visit. Median TFV-DP concentrations were significantly higher in those HIV-1 genotype did not amplify due to being virally suppressed at the subsequent visit (n = 10; 380 [227-661] fmol/punch, p = 0.035; EA 45 [24.9; 59.2]%); than in those who were successfully genotyped with evidence of drug resistance (n = 5, 241 [150-247] fmol/punch, EA 20 [6.7;36.7]%) and in individuals who did not have resistance (n = 3, 39.9 [16.6; 93.9] fmol/punch; EA 33.3 [16-38]%). Three genotype collections were not done. Only non-nucleoside reverse transcriptase inhibitor-associated mutations were identified on resistance testing. (K103N, E138K, Y118H). CONCLUSION: TFV-DP in DBS showed a step-wise inverse relationship with VB and drug resistance, with evidence of low cumulative ART adherence in PWH who developed antiretroviral resistance. Monitoring TFV-DP concentrations could be a valuable tool for predicting future VB and future resistance.

Evaluating the impact of antiretroviral and antiseizure medication interactions on treatment effectiveness among outpatient clinic attendees with HIV in Zambia.

OBJECTIVE: Interactions between enzyme-inducing anti-seizure medications (EI-ASMs) and antiretroviral drugs (ARVs) can lead to decreased ARV levels and may increase the likelihood of viral resistance. We conducted a study to determine if co-usage of ARVs and EI-ASMs is associated with ARV-resistant human immunodeficiency virus (HIV) among people living with HIV in Zambia. METHODS: Eligible participants were ≥18 years of age and concurrently taking ASMs and ARVs for at least 1 month of the prior 6-month period. Data were obtained regarding medication and HIV history. CD4 counts, plasma viral loads (pVLs), and HIV genotype and resistance profile in participants with a pVL >1000 copies/mL were obtained. Pearson's test of independence was used to determine whether treatment with EI-ASM was associated with pVL >1000/mL copies. RESULTS: Of 50 participants, 41 (82%) were taking carbamazepine (37 on monotherapy), and all had stable regimens in the prior 6 months. Among the 13 ARV regimens used, 68% had a tenofovir/lamivudine backbone. The majority (94%) were on a stable ARV regimen for >6 months. Median CD4 nadir was 205 cells/mm3 (interquartile range [IQR] 88-389), and 60% of participants had commenced ARV treatment before advanced disease occurred. Mean CD4 count at enrollment was 464 cells/mm3 (SD 226.3). Seven participants (14%) had a CD4 count <200 cells/mm3 . Four (8%) had a pVL >1000 copies/mL; all were on carbamazepine. Three participants with elevated pVL had a CD4 count <200 cells/mm3 . None had documented adherence concerns by providers; however, two had events concerning for clinical failure. HIV genotype testing showed mutations in three participants. Carbamazepine was not found to correlate with elevated pVL (P = .58). SIGNIFICANCE: EI-ASMs are commonly used in sub-Saharan Africa. Despite concurrent use of EI-ASMs and ARVs, the majority of participants showed CD4 counts >200 cells/mm3 and were virally suppressed. Carbamazepine was not associated with an increased risk of virological failure or ARV-resistant HIV.

Delayed linkage to HIV care among asylum seekers in Quebec, Canada.

BACKGROUND: Migrants represent an increasing proportion of people living with HIV in many developed countries. We aimed to describe the HIV care cascade and baseline genotypic resistance for newly diagnosed asylum seekers referred to the McGill University Health Centre (MUHC) in Montreal, Quebec, Canada. METHODS: We conducted a retrospective cohort study of patients linked to the MUHC from June 1, 2017 to October 31, 2018. We calculated the median time (days; interquartile range (IQR)) from: 1) entry into Canada to immigration medical examination (IME) (i.e. HIV screening); 2) IME to patient notification of diagnosis; 3) notification to linkage to HIV care (defined as a CD4 or viral load (VL) measure); 4) linkage to HIV care to combination antiretroviral therapy (cART) prescription; and 5) cART prescription to viral suppression (defined as a VL < 20 copies/mL). We reviewed baseline genotypes and interpreted mutations using the Stanford University HIV Drug Resistance Database. We calculated the proportion with full resistance to > 1 antiretroviral. RESULTS: Overall, 43% (60/139) of asylum seekers were newly diagnosed in Canada. Among these, 62% were late presenters (CD4 < 350 cells/µl), 22% presented with advanced HIV (CD4 < 200 cells/µl), and 25% with high-level viremia (VL > 100,000 copies/ml). Median time from entry to IME: 27 days [IQR:13;55]; IME to notification: 28 days [IQR:21;49]; notification to linkage: 6 days [IQR:2;19]; linkage to cART prescription: 11 days [IQR:6;17]; and cART to viral suppression: 42 days [IQR:31;88]; 45% were linked to HIV care within 30 days. One-fifth (21%) had baseline resistance to at least one antiretroviral agent; the K103 N/S mutation was the most common mutation. CONCLUSIONS: While the majority of newly diagnosed asylum seekers were late presenters, only 45% were linked to care within 30 days. Once linked, care and viral suppression were rapid. Delays in screening and linkage to care present increased risk for onward transmission, and in the context of 21% baseline resistance, consideration of point-of-care testing and immediate referral at IME screening should be made.

Antiretroviral resistance in HIV-1 patients at a tertiary medical institute in Saudi Arabia: a retrospective study and analysis.

BACKGROUND: Since the early 90's antiretroviral drugs have been available at King Faisal Specialist Hospital and Research Centre (KFSH&RC), a referral hospital in Riyadh, Saudi Arabia, for the treatment of both adults and children infected with HIV-1. However, up to date, there are no genetic profiling data for the resistance-causing mutations in HIV-1 virus in patients on antiretroviral drugs therapy. This paper presents an initial report and a profiling survey of drug resistance-associated mutations of 103 HIV-1 patients seen at KFSH&RC. METHODS: This is a retrospective study on Patients treated at KFSH&RC since 2003 up to 2016. The analysis was done on the drug resistance mutations profiles of 103 patients who were undergoing highly active antiretroviral therapy protocols. RESULTS: Our analysis shows that the drug resistance mutations reported in our treatment cohort of HIV-infected adults patients is similar what is internationally reported to some extent. Additionally, we have identified novel drug resistance causing mutations. Furthermore, different profile of drug resistance causing mutations was also observed. CONCLUSION: Patients showed both similar and new drug resistant causing mutations, early identification of these mutations is crucial to guide and avoid failure future therapy.

Targeting of mTOR catalytic site inhibits multiple steps of the HIV-1 lifecycle and suppresses HIV-1 viremia in humanized mice.

HIV necessitates host factors for successful completion of its life cycle. Mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase that forms two complexes, mTORC1 and mTORC2. Rapamycin is an allosteric inhibitor of mTOR that selectively inhibits mTORC1. Rapamycin interferes with viral entry of CCR5 (R5)-tropic HIV and with basal transcription of the HIV LTR, potently inhibiting replication of R5 HIV but not CXCR4 (X4)-tropic HIV in primary cells. The recently developed ATP-competitive mTOR kinase inhibitors (TOR-KIs) inhibit both mTORC1 and mTORC2. Using INK128 as a prototype TOR-KI, we demonstrate potent inhibition of both R5 and X4 HIV in primary lymphocytes (EC50 < 50 nM), in the absence of toxicity. INK128 inhibited R5 HIV entry by reducing CCR5 levels. INK128 also inhibited both basal and induced transcription of HIV genes, consistent with inhibition of mTORC2, whose activity is critical for phosphorylation of PKC isoforms and, in turn, induction of NF-κB. INK128 enhanced the antiviral potency of the CCR5 antagonist maraviroc, and had favorable antiviral interactions with HIV inhibitors of reverse transcriptase, integrase and protease. In humanized mice, INK128 decreased plasma HIV RNA by >2 log10 units and partially restored CD4/CD8 cell ratios. Targeting of cellular mTOR with INK128 (and perhaps others TOR-KIs) provides a potential strategy to inhibit HIV, especially in patients with drug resistant HIV strains.

Next-Generation Human Immunodeficiency Virus Sequencing for Patient Management and Drug Resistance Surveillance.

High-quality, simplified, and low-cost human immunodeficiency virus (HIV) drug resistance tests that are able to provide timely actionable HIV resistance data at individual, population, and programmatic levels are needed to confront the emerging drug-resistant HIV epidemic. Next-generation sequencing technologies embedded in automated cloud-computing analysis environments are ideally suited for such endeavor. Whereas NGS can reduce costs over Sanger sequencing, automated analysis pipelines make NGS accessible to molecular laboratories regardless of the available bioinformatic skills. They can also produce highly structured, high-quality data that could be examined by healthcare officials and program managers on a real-time basis to allow timely public health action. Here we discuss the opportunities and challenges of such an approach.

Virological failure and development of new resistance mutations according to CD4 count at combination antiretroviral therapy initiation.

OBJECTIVES: No randomized controlled trials have yet reported an individual patient benefit of initiating combination antiretroviral therapy (cART) at CD4 counts > 350 cells/µL. It is hypothesized that earlier initiation of cART in asymptomatic and otherwise healthy individuals may lead to poorer adherence and subsequently higher rates of resistance development. METHODS: In a large cohort of HIV-positive individuals, we investigated the emergence of new resistance mutations upon virological treatment failure according to the CD4 count at the initiation of cART. RESULTS: Of 7918 included individuals, 6514 (82.3%), 996 (12.6%) and 408 (5.2%) started cART with a CD4 count ≤ 350, 351-499 and ≥ 500 cells/µL, respectively. Virological rebound occurred while on cART in 488 (7.5%), 46 (4.6%) and 30 (7.4%) with a baseline CD4 count ≤ 350, 351-499 and ≥ 500 cells/µL, respectively. Only four (13.0%) individuals with a baseline CD4 count > 350 cells/µL in receipt of a resistance test at viral load rebound were found to have developed new resistance mutations. This compared to 107 (41.2%) of those with virological failure who had initiated cART with a CD4 count < 350 cells/µL. CONCLUSIONS: We found no evidence of increased rates of resistance development when cART was initiated at CD4 counts above 350 cells/µL.

Safety and efficacy of coformulated efavirenz/emtricitabine/tenofovir single-tablet regimen in treatment-naive patients infected with HIV-1.

Due to the differences between bioavailability of efavirenz (EFV) and tenofovir (TDF), the single-tablet regimen of EFV/emtricitabine (FTC)/TDF is not approved as initial antiretroviral therapy (ART) in Europe by the European Medical Agency. To compare clinical, immunological, and virological outcomes between co-formulated TDF/FTC+EFV and the co-formulated EFV/FTC/TDF single-tablet regimen in patients infected with HIV-1 naive to ART, the data of patients (n = 231) who initiated either TDF/FTC+EFV (n = 155) or EFV/FTC/TDF (n = 76) between January 1, 2007 and June 1, 2010 were analyzed. Changes from baseline to week 48 (TDF/FTC+EFV vs. EFV/FTC/TDF) in HIV plasma load (- 3.25 log vs. -3.32 log) and CD4+ T cell count (+180 vs. +138 cells/mm3) were similar in the two groups. Treatment discontinuation was recorded in 50 (22%) patients (40 on TDF/FTC+EFV and 10 on EFV/FTC/TDF, P = 0.03) but time to discontinuation did not differ between the two groups. Only patients on TDF/FTC+EFV discontinued treatment because of neurological symptoms. Virological failure occurred in 11 (4.7%) patients (seven on TDF/FTC+EFV and four on EFV/FTC/TDF, P = 0.75) with new resistance-associated mutations in five among the six with successful resistance genotype tests. Only baseline resistance-associated mutations was a risk factor for virological failure (P = 0.0146). These data show comparable outcomes between TDF/FTC+EFV or EFV/FTC/TDF used in patients infected with HIV-1 and not treated previously, consistent with a low rate of virological failure in the absence of pretreatment resistance. This would suggest that the European Medical Agency should approve co-formulated EFV/FTC/TDF single-tablet regimen for patients naive to ART.

Pretreatment HIV-1 Resistance in Argentina: Results from the Second Surveillance Study Following World Health Organization Guidelines (2019).

More than 62,000 individuals are currently on antiretroviral treatment within the public health system in Argentina. In 2019, more than 50% of people on ART received non-nucleoside reverse transcriptase inhibitors (NNRTIs). In this context, the second nationwide HIV-1 pretreatment drug resistance surveillance study was carried out between April and December 2019 to assess the prevalence of HIV-1 drug resistance in Argentina using the World Health Organization guidelines. This was a nationwide cross-sectional study enrolling consecutive 18-year-old and older individuals starting ARVs at 19 ART-dispensing centers. This allowed us to estimate a point prevalence rate of resistance-associated mutations (RAMs) with a confidence interval (CI) of 5% (for the total population and for those without antiretroviral exposure). Four-hundred forty-seven individuals were included in the study. The prevalence of mutations associated with resistance was detected in 27.7% (95% CI 25.6-34.9%) of the population. For NNRTI, it was 19.6% (95% CI 16.3-24.5%), for integrase strand transfer inhibitor (INSTI) 6.1% (95% CI 6.1-11.9%), for nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) 3% (95% CI 1.9-5.9%), and for protease inhibitors 1.5% (95% CI 0.7-3.6%). Naive individuals had variants of resistance to NRTIs in 16.8% (95% CI 12.8-21.4) and 5.7% (95% CI 2.9-15.9) to INSTI. For experienced individuals, the prevalence of variants associated with resistance was 30.38% (95% CI 20.8-42.2) for NRTIs and 7.7% (95% CI 2.9-15.9) for INSTI. This study shows an increase in the frequency of nonpolymorphic RAMs associated with resistance to NNRTI. This study generates the framework of evidence that supports the use of schemes based on high genetic barrier integrase inhibitors as the first line of treatment and the need for the use of resistance test before prescribing schemes based on NNRTI. We report for the first time the presence of a natural polymorphism associated with the most prevalent recombinant viral form in Argentina and the presence of a mutation linked to first-line integrase inhibitors such as raltegravir.

Highly multidrug-resistant HIV: clonal analysis and therapeutic strategies.

OBJECTIVES: There are today HIV-infected patients in therapeutic impasses because of highly multidrug-resistant (HMDR) viruses. We studied the distribution of resistance mutations at clonal level, and we analysed the therapeutic strategies used in such cases to achieve undetectable viraemia. METHODS: The HMDR profile was defined as a genotypic sensitivity score (GSS) ≤ 1.5 for etravirine and raltegravir with full resistance to darunavir. About 30 clones per gene and per patient were sequenced. Virtual phenotypes were determined. Efficacy of therapeutic strategies was evaluated by follow-up of viral loads, CD4 cell counts and trough concentrations of drugs. RESULTS: Among 1310 patients on treatment and with genotypic resistance testing, 25 (2%) were resistant to darunavir and 11 (0.8%) had an HMDR profile. Five-hundred clones could be analysed for four of them. HMDR profiles were harboured by the great majority of clones and all resistance mutations were located on the same strains for all genes. Despite this and a regimen with a GSS <2.0 in three patients, they achieved a viraemia <20 copies/mL. These results were obtained using different strategies: high doses of drugs; combination of antiretrovirals with full or intermediate susceptibility, such as tipranavir, etravirine or maraviroc; and use of alternative compounds, such as foscarnet or interferon. CONCLUSION: Patients with HMDR HIV were uncommon, but, in such cases, all resistance mutations were borne on the same majority strains. In this study, tipranavir was the only protease inhibitor with full or intermediate susceptibility. Despite very limited therapeutic options, an undetectable viraemia can be achieved by combining different strategies.

Lenacapavir: A first-in-class capsid inhibitor for the treatment of highly treatment-resistant HIV.

PURPOSE: The purpose of this article is to review the pharmacology, efficacy, and safety of the capsid inhibitor lenacapavir for the treatment of multidrug-resistant human immunodeficiency virus type 1 (HIV-1) infection. SUMMARY: A review of the literature was performed by searching PubMed/MEDLINE for all relevant articles published between February 2021 and March 2023 using the keywords "lenacapavir," "Sunlenca," "human immunodeficiency virus," and "treatment" together with "multidrug resistant human immunodeficiency virus." All English-language articles describing clinical trials assessing the efficacy and safety of lenacapavir when used in humans for the treatment of HIV infection were included. Review articles, conference abstracts, and article references were evaluated for relevant information, and data were also obtained from the manufacturer's website and the package insert. Lenacapavir has been approved by the Food and Drug Administration (FDA) for the treatment of HIV-1 infection in heavily treatment-experienced adults with multidrug resistance for whom the current antiretroviral regimen is failing due to resistance, intolerance, or safety considerations. It is the first in a new class of drugs called capsid inhibitors to receive FDA approval. Lenacapavir is a long-acting subcutaneous injectable to be administered once every 6 months. The phase 3 clinical trial evaluating lenacapavir has demonstrated its efficacy in viral load reduction from baseline compared to placebo in patients receiving optimized background therapy. The most common adverse events reported in the clinical trial were injection site reactions, occurring in 63% of participants. CONCLUSION: Lenacapavir is a novel capsid inhibitor indicated, in combination with other antiretroviral therapy, for treatment of multidrug-resistant HIV-1 infection.

HIV: how to manage heavily treatment-experienced patients.

Although decreasing in prevalence, heavily treatment-experienced (HTE) persons with limited options for HIV treatment present unique complexities, even amongst experienced providers, as there is no single approach to successful management. HTE patients are described as those having two or less antiretroviral (ARV) classes available for use with limited fully active ARV agents within each class. A detailed understanding of the underlying processes that caused previous treatment failures, diagnostics to define resistance, resistance mechanisms and ARV pharmacology should all function in tandem to determine the next steps of clinical care. This narrative review provides an overview of the clinician approach to care, including diagnostics, approaches to regimen creation, relevant resources, and a broad array of both currently available and upcoming ARVs that may be used in regimens for HTE patients.

Prevalence and Evolution of Transmitted Human Immunodeficiency Virus Drug Resistance in Belgium Between 2013 and 2019.

Background: To assess the prevalence and evolution of transmitted drug resistance (TDR) in Belgium, a total of 3708 baseline human immunodeficiency virus (HIV)-1 polymerase sequences from patients diagnosed between 2013 and 2019 were analyzed. Methods: Protease and reverse-transcriptase HIV-1 sequences were collected from the 7 national Aids Reference Laboratories. Subtype determination and drug resistance scoring were performed using the Stanford HIV Drug Resistance Database. Trends over time were assessed using linear regression, and the maximum likelihood approach was used for phylogenetic analysis. Results: A total of 17.9% of the patients showed evidence of TDR resulting in at least low-level resistance to 1 drug (Stanford score ≥15). If only the high-level mutations (Stanford score ≥60) were considered, TDR prevalence dropped to 6.3%. The majority of observed resistance mutations impacted the sensitivity for nonnucleoside reverse-transcriptase inhibitors (NNRTIs) (11.4%), followed by nucleoside reverse-transcriptase inhibitors (6.2%) and protease inhibitors (2.4%). Multiclass resistance was observed in 2.4%. Clustered onward transmission was evidenced for 257 of 635 patients (40.5%), spread over 25 phylogenetic clusters. Conclusions: The TDR prevalence remained stable between 2013 and 2019 and is comparable to the prevalence in other Western European countries. The high frequency of NNRTI mutations requires special attention and follow-up. Phylogenetic analysis provided evidence for local clustered onward transmission of some frequently detected mutations.

Tenofovir diphosphate levels in dried blood spots are associated with virologic failure and resistance to first-line therapy in South Africa: a case-control cohort study.

INTRODUCTION: Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS), a measure of cumulative antiretroviral therapy (ART) adherence, is associated with viral suppression and predicts future viremia in persons with HIV (PWH). However, its utility to identify those at risk for virologic failure (VF) and drug resistance is unknown. To address this, we aimed to establish the association between this adherence biomarker and VF with drug resistance in a cohort of PWH initiating first-line ART in KwaZulu-Natal, South Africa. METHODS: PWH initiating TFV disoproxil fumarate (TDF)-based ART within a parent prospective cohort were evaluated. Using a nested design, DBS for TFV-DP were collected from cases who developed VF (HIV-1 RNA ≥1000 copies/ml) after ≥5 months on ART versus controls, matched 1:2 by site, age, gender, race and ART duration. Cases were categorized as having VF with or without resistance using genotyping. One-way analysis of variance (ANOVA) was used to compare TFV-DP for controls, cases with VF and resistance, and cases with VF without resistance. Data are presented as mean (standard deviation, SD) or geometric mean [95% confidence interval, 95% CI]. RESULTS AND DISCUSSION: One thousand participants were enrolled in the parent study between 2014 and 2016, of which 288 (29%) had DBS available. Of these, 94 (33%) were cases and 194 (67%) were controls; 59% were women. Mean age of our population was 33 (SD 8) years. Genotyping was available in 50 (53%) of the 94 cases. Geometric mean TFV-DP in DBS from controls was 708 [95% CI; 647-773] fmol/punch, which was higher compared to participants having VF with resistance (n = 36), 386 [95% CI; 241-617] fmol/punch and VF without resistance (n = 14), 61 [95% CI; 22-164] fmol/punch; p<0.001. Genotype could not be obtained in 44 (47%) cases. CONCLUSIONS: TFV-DP in DBS showed a stepwise association with VF and drug resistance in South African PWH. Participants having VF with resistance had mid-range concentrations of TFV-DP, which were higher than those for PWH without resistance. Future research on the clinical utility of TFV-DP concentrations in DBS to predict and prevent the development of VF and drug resistance is needed.

Presence of V72I, G123S and R127K Integrase Inhibitor polymorphisms could reduce ART effectiveness: a retrospective longitudinal study.

Objectives: Structural aspects of HIV-1 integrase complex and role of integrase minor mutations and polymorphisms in ART effectiveness is still unknown. The objective of this study was to assess the 24 and 48 weeks (W) effectiveness of ART regimens in patients with Integrase Inhibitors (InSTI) minor mutations and polymorphisms receiving InSTI-based regimens.Methods: We enrolled all ART-naïve or InSTI-naïve HIV-infected patients, with a baseline InSTI genotypic resistances test between 2011 and 2016. We analyzed integrase resistance mutations using the Stanford University HIV Drug Resistance Database (HIVdb Program, version 6.3.0). The outcome was virological response at 24 and 48 W of follow up (FU) according to snapshot analysis. We defined virological failure as two consecutive HIV-RNA > 50 copies/ml, or one >1000 copies/ml. Patients were divided in those presenting InSTI minor mutations (Group 1), and those with only polymorphisms or wild type (Group 2).Results: We enrolled 83 patients. 81 patients reached 24 W of FU: 2/20 (10%) and 4/61 (6.5%) showed virological failure in Group 1 and 2 respectively. 66 patients reached 48 W of FU: 0/17 (0%) and 2/49 (4%) showed virological failure in Group 1 and 2 respectively. Interestingly, patients with polymorphisms G123S and R127K had higher risk of failure at 24 W (respectively, relative risk - RR - 36, IQR 2.1-613, p = 0.01; RR 36, IQR 2.1-613, p = 0.01) and patients with V72I had an higher risk of failure both at 24 W (RR 6.52, IQR 1.29-32.9, p = 0.02) and 48 W (RR 21.1, IQR 1.07-414, p = 0.04).Conclusions: Our study showed that the presence of V72I, G123S and R127K polymorphisms could play a role in reducing InSTI effectiveness.

Targeting Integrase Enzyme: A Therapeutic Approach to Combat HIV Resistance.

Global Human Immunodeficiency Virus (HIV) statistics by the World Health Organization (WHO) for the year 2017 was estimated to be 36.9 (31.1-43.9) million. Antiviral drug resistance poses a serious threat to public health and requires immediate action. Retroviral Integrase (IN), a component enzyme in the retroviral pre-integration complex (PIC) enables a retrovirus to incorporate its genetic material into the host DNA. Development of resistance by the current integrases invites immediate attention of the drug discovery community for the development of new second-generation Integrase Strand Transfer Inhibitors (INSTIs). It will exhibit greater efficacy against Elvitegravir (EVG) and Raltegravir (RAL) resistant strains of HIV. This review focuses on the mechanism, importance of integrase structure, function and current research on small molecule inhibitors of integrase to overcome drug resistance. The molecular mechanism of retroviral integrase inhibition and the evolution of resistance are also explored.