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Objective: To date, no data exist regarding the prevalence of integrase inhibitor (INSTI) resistance-associated mutations (HIVDRM) in HIV-infected pregnant women (HPW) in Latin America. We describe the prevalence and transmissibility of integrase HIVDRM in a historical cohort of INSTI-naïve HPW from Argentina (n=56) with Next Generation Sequencing (NGS)., Methods: Bioinformatics analysis was performed by HyDRA software for 20%, 10%, 5%, 2%, and 1% sensitivity thresholds. We calculated the mutational viral load for each INSTI-HIVDRM, considering those with >1000 c/mL as of high risk of transmissibility., Results: The predominant HIV subtype was BF (78.5%). Major HIVDRM were not detected with the population sequencing 20% filter. With a 1% threshold, the prevalence increased to 8.9%; Y143C/S, E92G, E138K, and T66I mutations were found. The median (range) mutational load (expressed in c/mL) was: 355 (50.2-11705); with only 1 case >1000 c/mL Accessory mutations (G163R/K, T97A) were detected mostly with a 20% sensitivity threshold with an overall prevalence of 23.2%; the median (IQR) mutational load was: 23929 (4009-63158) c/mL; all of them above 1000 c/mL., Conclusions: Our results show evidence of the presence of major INSTI-HIVDRM as aleatory mutations and a high frequency of accessory mutations with potential transmissibility in HPW., (©The Author 2024. Published by Sociedad Española de Quimioterapia. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)(https://creativecommons.org/licenses/by-nc/4.0/).)

Background: Currently, most HIV drug resistance PCR assays amplify the protease-reverse transcriptase (PR-RT) fragment separately from the integrase (IN) fragment. The aim of this study was to develop a multiplex PCR assay that simultaneously amplifies PR-RT and IN fragments for HIV-1 drug-resistance testing., Methods: The in-house multiplex PCR assay was evaluated on extracted total nucleic acids obtained from the National Health Laboratory Service (NHLS) and Lancet laboratories. Sanger sequencing was performed on amplicons, and HIV-1 drug-resistance mutations (DRMs) were assessed using HIV Stanford drug resistance database., Results: This study tested 59 patient samples with known HIV-1 viral load and DRM results; 41 from Lancet and 18 from NHLS. In-house multiplex PCR assay detected one or both fragments in most samples but had higher sensitivity for detection of IN fragment (93.2 %) compared to PR-RT fragment (83.1 %). There was 100 % concordance between Lancet assay versus in-house assay sequence data for IN DRMs, but lower concordance with PR-RT (87.0 %). The in-house multiplex PCR assay's precision and reproducibility analysis showed ≥99.9 % sequence similarity and yielded similar DRM results for both PR-RT and IN fragments., Conclusions: The in-house multiplex PCR assay demonstrated satisfactory performance and higher sensitivity for IN fragment amplification. This could be a cost-effective method for HIV-1 drug resistance testing as both PR-RT and IN fragments are successfully amplified in one reaction in most samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

A newer integrase strand transfer inhibitor (INSTI) cabotegravir was recently approved for both therapy and prophylaxis and can play an essential role in the fight against AIDS. It shares similar resistance profile to dolutegravir, the cornerstone of Brazilian antiretroviral (ARV) treatment, with about 600 thousand people living with HIV in Brazil currently on regimens that contain this INSTI. Health services in the São Paulo metropolitan area are responsible for a large proportion of ARV dispensation in the country. Estimating transmitted drug resistance mutation (TDRM) in the area before cabotegravir introduction may provide a useful baseline information. Partial HIV-1 pol gene was sequenced (Sanger) from 192 newly diagnosed individuals from São Paulo and nearby cities (2020 to March 2023) at integrase, with 85 also at protease/reverse transcriptase regions. Retrotranscribed plasma RNA, amplified with nested PCR, was edited (Recall or Sequencher) and analyzed at Rega and Stanford db. Surveillance drug resistance mutations (SDRM) to INSTI class was detected in three cases (1.6%; 95% CI: 0.5%-5%), two E138K and one R263K, with 7.8% (95% CI: 5%-13%) with resistance mutations (major or accessory). SDRM for nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and PI classes were identified in 7 (8.2% CI: 95% 4%-16%) cases. Subtype B predominated (69%), followed by subtype C (16%), now the second most prevalent infection in this area. Among 131 patients treated for over 6 months, 92% were virally suppressed below 200 copies/mL, with low TCD4 counts independently associated to failure. SDRM to INSTI class is rare in the area. Intermediate rates of transmitted resistance to other ARV classes are comparable to previous estimates. Viral suppression rates may depend on TCD4 counts, another negative impact of late diagnosis in care that deserves more attention.

Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are investigational antiretroviral agents that potently impair virion maturation by inducing hyper-multimerization of IN and inhibiting its interaction with viral genomic RNA. The pyrrolopyridine-based ALLINI pirmitegravir (PIR) has recently advanced into phase 2a clinical trials. Previous cell culture-based viral breakthrough assays identified the HIV-1 (Y99H/A128T IN) variant that confers substantial resistance to this inhibitor. Here, we have elucidated the unexpected mechanism of viral resistance to PIR. Although both Tyr99 and Ala128 are positioned within the inhibitor binding V-shaped cavity at the IN catalytic core domain (CCD) dimer interface, the Y99H/A128T IN mutations did not substantially affect the direct binding of PIR to the CCD dimer or functional oligomerization of full-length IN. Instead, the drug-resistant mutations introduced a steric hindrance at the inhibitor-mediated interface between CCD and C-terminal domain (CTD) and compromised CTD binding to the CCD Y99H/A128T + PIR complex. Consequently, full-length IN Y99H/A128T was substantially less susceptible to the PIR-induced hyper-multimerization than the WT protein, and HIV-1 (Y99H/A128T IN) conferred >150-fold resistance to the inhibitor compared with the WT virus. By rationally modifying PIR, we have developed its analog EKC110, which readily induced hyper-multimerization of IN Y99H/A128T in vitro and was ~14-fold more potent against HIV-1 (Y99H/A128T IN) than the parent inhibitor. These findings suggest a path for developing improved PIR chemotypes with a higher barrier to resistance for their potential clinical use.IMPORTANCEAntiretroviral therapies save the lives of millions of people living with HIV (PLWH). However, the evolution of multi-drug-resistant viral phenotypes is a major clinical problem, and there are limited or no treatment options for heavily treatment-experienced PLWH. Allosteric HIV-1 integrase inhibitors (ALLINIs) are a novel class of antiretroviral compounds that work by a unique mechanism of binding to the non-catalytic site on the viral protein and inducing aberrant integrase multimerization. Accordingly, ALLINIs potently inhibit both wild-type HIV-1 and all drug-resistant viral phenotypes that have so far emerged against currently used therapies. Pirmitegravir, a highly potent and safe investigational ALLINI, is currently advancing through clinical trials. Here, we have elucidated the structural and mechanistic bases behind the emergence of HIV-1 integrase mutations in infected cells that confer resistance to pirmitegravir. In turn, our findings allowed us to rationally develop an improved ALLINI with substantially enhanced potency against the pirmitegravir-resistant virus., Competing Interests: Kyungjin Kim was the chief executive officer of ST Pharm Co. Ltd. No other authors declare a potential conflict of interest.

Retroviruses perpetuate their survival by incorporating a copy of their genome into the host cell, a critical step catalyzed by the virally encoded integrase. The viral capsid plays an important role during the viral life cycle, including nuclear importation in the case of lentiviruses and integration targeting events; hence, targeting the integrase and the viral capsid is a favorable therapeutic strategy. While integrase strand transfer inhibitors (INSTIs) are recommended as first-line regimens given their high efficacy and tolerability, lenacapavir is the first capsid inhibitor and the newest addition to the HIV treatment arsenal. These inhibitors are however designed for treatment of HIV-1 infection, and their efficacy against HIV-2 remains widely understudied and inconclusive, supported only by a few limited phenotypic susceptibility studies. We therefore carried out inhibition profiling of a panel of second-generation INSTIs and lenacapavir against HIV-2 in cell culture, utilizing pseudovirion inhibition profiling assays. Our results show that the tested INSTIs and lenacapavir exerted excellent efficacy against ROD-based HIV-2 integrase. We further evaluated the efficacy of raltegravir and other INSTIs against different variants of SARS-CoV-2; however, contrary to previous in silico findings, the inhibitors did not demonstrate significant antiviral activity.

With the widespread use of integrase inhibitors and the expanding use of long-acting cabotegravir in both pre-exposure prophylaxis and antiretroviral treatment, molecular surveillance on the transmission of integrase resistance has regained clinical significance. This study aimed to determine the frequency of INSTI-transmitted drug resistance mutations (DRMs) among treatment-naïve individuals in Poland from 2016 to 2023. INSTI resistance was analyzed in 882 antiretroviral treatment-naïve individuals using Sanger sequencing. Integrase DRMs were defined based on the Stanford HIV drug resistance database scores. Phylogeny was used to investigate subtyping and clustering. For the analysis of time-trends, logistic regression was used. Major (E138K and R263K) integrase mutations were detected in 0.45% of cases with minor resistance observed in 14.85%, most commonly (13.95%) E157Q. Overall, no major clusters of transmitted drug resistance were identified, and the transmission of E157Q showed a decreasing trend ( p < 0.001). While the frequency of sub-subtype A6 increased, it was predominantly found among migrants and associated with L74 mutations. The frequency of major integrase-transmitted DRMs remains low, despite the changes in subtype variability. Surveillance of changing HIV molecular variation patterns is vital from the perspective of the optimal use of integrase inhibitors, especially due to expanding long-acting cabotegravir implementation.

Objective: Assessing the prevalence of resistance and drug resistance mutations (DRMs) in HIV/AIDS patients towards integrase strand transfer inhibitors (INSTIs), particularly the 2nd-generation INSTIs, provides evidence for rational clinical drug use., Methods: A systematic search was conducted on five databases to identify relevant literature reporting original data on INSTIs resistance. Meta-analyses, cumulative meta-analyses, subgroup analyses and meta-regression analyses were performed using selected models based on the results of heterogeneity tests., Results: A total of 81 studies were included in this analysis. The prevalence of pre-treatment drug resistance (PDR) to 1st-generation INSTIs and 2nd-generation INSTIs were 0.41% (95% CI: 0.19%-0.70%) and 0.04% (95% CI: 0.00%-0.13%), respectively; and the prevalence of acquired drug resistance (ADR) were 7.60% (95% CI: 3.54%-12.92%) and 4.93% (95% CI: 1.78%-9.36%), respectively, and ADR showed an increasing and then decreasing time trend. The results of subgroup analyses showed differences in ADR to 2nd-generation INSTIs between regions and economic levels, with the highest ADR of 12.83% (95% CI: 3.24%-27.17%) in the European region. DRMs varied among HIV patients and reduced drug sensitivity to varying degrees., Conclusion: The prevalence of PDR and DRMs in 2nd-generation INSTIs is currently low, but as the use of DTG-based ART expands, population-level drug resistance monitoring and individual-level genetic testing should be strengthened in order to maximise treatment efficacy. Additionally, attention should be paid to ADR to INSTIs to provide personalised treatments for HIV-infected patients., (Copyright © 2024 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.)

Retroviral integration is mediated by intasome nucleoprotein complexes wherein a pair of viral DNA ends are bridged together by a multimer of integrase (IN). Atomic-resolution structures of HIV-1 intasomes provide detailed insights into the mechanism of integration and inhibition by clinical IN inhibitors. However, previously described HIV-1 intasomes are highly heterogeneous and have the tendency to form stacks, which is a limiting factor in determining high-resolution cryo-EM maps. We have assembled HIV-1 intasomes in the presence of excess IN C-terminal domain protein, which was readily incorporated into the intasomes. The purified intasomes were largely homogeneous and exhibited minimal stacking tendencies. The cryo-EM map resolution was further improved to 2.01 Å, which will greatly facilitate structural studies of IN inhibitor action and drug resistance mechanisms. The C-terminal 18 residues of HIV-1 IN, which are critical for virus replication and integration in vitro, have not been well resolved in previous intasome structures, and its function remains unclear. We show that the C-terminal tail participates in intasome assembly, resides within the intasome core, and forms a small alpha helix (residues 271-276). Mutations that disrupt alpha helix integrity impede IN activity in vitro and disrupt HIV-1 infection at the step of viral DNA integration.

The WHO currently recommends dolutegravir (DTG)-based ART for persons living with HIV infection in resource-limited-settings (RLS). To expand access to testing for HIV drug resistance (DR) to DTG in RLS, we developed probes for use in the oligonucleotide ligation assay (OLA)-Simple, a near-point of care HIV DR kit. Genotypic data from clinical trials and case reports were used to determine the mutations in HIV-1 integrase critical to identifying individuals with DTG-resistance at virologic failure of DTG-based ART. Probes to detect G118R, Q148H/K/R, N155H and R263K in HIV-1 subtypes A, B, C, D and CRF01&#95;AE were designed using sequence alignments from the Los Alamos database and validated using 61 clinical samples of HIV-1 subtypes A, B, C, D, CRF01&#95;AE genotyped by PacBio ( n = 15) or Sanger ( n = 46). Initial OLA probes failed to ligate for 16/244 (6.5%) codons (9 at G118R and 7 at Q148H/K/R). Probes revised to accommodate polymorphisms interfering with ligation at codons G118R and Q148R reduced indeterminates to 3.7% (5 at G118R and 4 at Q148H/K/R) and detected DTG-mutations with a sensitivity of 96.5% and 100% specificity. These OLA DTG resistance probes appear highly sensitive and specific across HIV-1 subtypes common in RLS with high burden of HIV infection.

The surveillance of drug resistance in the HIV-1 naïve population remains critical to optimizing the effectiveness of antiretroviral therapy (ART), mainly in the era of integrase strand transfer inhibitor (INSTI) regimens. Currently, there is no data regarding resistance to INSTI in Angola since Dolutegravir-DTG was included in the first-line ART regimen. Herein, we investigated the HIV-1 genetic diversity and pretreatment drug resistance (PDR) profile against nucleoside/tide reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and INSTIs, using a next-generation sequencing (NGS) approach with MinION, established to track and survey DRMs in Angola. This was a cross-sectional study comprising 48 newly HIV-diagnosed patients from Luanda, Angola, screened between March 2022 and May 2023. PR, RT, and IN fragments were sequenced for drug resistance and molecular transmission cluster analysis. A total of 45 out of the 48 plasma samples were successfully sequenced. Of these, 10/45 (22.2%) presented PDR to PIs/NRTIs/NNRTIs. Major mutations for NRTIs (2.2%), NNRTIs (20%), PIs (2.2%), and accessory mutations against INSTIs (13.3%) were detected. No major mutations against INSTIs were detected. M41L (2%) and I85V (2%) mutations were detected for NRTI and PI, respectively. K103N (7%), Y181C (7%), and K101E (7%) mutations were frequently observed in NNRTI. The L74M (9%) accessory mutation was frequently observed in the INSTI class. HIV-1 pure subtypes C (33%), F1 (17%), G (15%), A1 (10%), H (6%), and D (4%), CRF01&#95;AG (4%) were observed, while about 10% were recombinant strains. About 31% of detected HIV-1C sequences were in clusters, suggesting small-scale local transmission chains. No major mutations against integrase inhibitors were detected, supporting the continued use of INSTI in the country. Further studies assessing the HIV-1 epidemiology in the era of INSTI-based ART regimens are needed in Angola., (© 2024. The Author(s).)

HIV genotyping is used to assess HIV susceptibility to antiretroviral drugs. The Applied Biosystems HIV-1 Genotyping Kit with Integrase (AB kit, Thermo Fisher Scientific) detects resistance-associated mutations (RAMs) in HIV protease (PR), reverse transcriptase (RT), and integrase (IN). We compared results from the AB kit with results obtained previously with the ViroSeq HIV-1 Genotyping System. DNA amplicons from the AB kit were also analyzed using next-generation sequencing (NGS). HIV RNA was extracted using the MagNA Pure 24 instrument (Roche Diagnostics; 96 plasma samples, HIV subtype B, viral load range: 530-737,741 copies/mL). FASTA files were generated from AB kit data using Exatype (Hyrax Biosciences). DNA amplicons from the AB kit were also analyzed by NGS using the Nextera XT kit (Illumina). Drug resistance was predicted using the Stanford HIV Drug Resistance Database. The mean genetic distance for sequences from ViroSeq and the AB kit was 0.02% for PR/RT and 0.04% for IN; 103 major RAMs were detected by both methods. Four additional major RAMs were detected by the AB kit only. These four major RAMs were also detected by NGS (detected in 18.1%-38.2% of NGS reads). NGS detected 27 major RAMs that were not detected with either of the Sanger sequencing-based kits. All major RAMs detected with ViroSeq were detected with the AB kit; additional RAMs were detected with the AB kit only. DNA amplicons from the AB kit can be used for NGS for more sensitive detection of RAMs., Competing Interests: The authors declare no conflict of interest.

The pre-integration steps of the HIV-1 viral cycle are some of the most valuable targets of recent therapeutic innovations. HIV-1 integrase (IN) displays multiple functions, thanks to its considerable conformational flexibility. Recently, such flexible proteins have been characterized by their ability to form biomolecular condensates as a result of Liquid-Liquid-Phase-Separation (LLPS), allowing them to evolve in a restricted microenvironment within cells called membrane-less organelles (MLO). The LLPS context constitutes a more physiological approach to study the integration of molecular mechanisms performed by intasomes (complexes containing viral DNA, IN, and its cellular cofactor LEDGF/p75). We investigated here if such complexes can form LLPS in vitro and if IN enzymatic activities were affected by this LLPS environment. We observed that the LLPS formed by IN-LEDGF/p75 functional complexes modulate the in vitro IN activities. While the 3'-processing of viral DNA ends was drastically reduced inside LLPS, viral DNA strand transfer was strongly enhanced. These two catalytic IN activities appear thus tightly regulated by the environment encountered by intasomes., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The in vivo selection of E157Q plus R263K has not been reported in patients treated with coformulated bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). To the best of our knowledge, we hereby report the first case of high-grade INSTI resistance associated with the presence of these aminoacidic substitutions in a treatment-experienced HIV patient treated with BIC/FTC/TAF., Methods: Clinical case report and review of the literature., Results: A heavily treatment-experienced patient was switched to BIC/FTC/TAF due to drug-drug interactions after being diagnosed with disseminated Mycobacterium avium-intracellulare disease. He had been treated before with raltegravir with poor adherence. No mutations in the integrase gene were detected 1 year after finishing treatment with raltegravir. Months after being switched to BIC/FTC/TAF, and again with poor adherence documented, virological failure (VF) was detected. The polymorphic substitution E157Q and the resistance mutation R263K in the integrase gene were detected, as well as M184V, among other mutations in the reverse transcriptase gene. The patient is currently being treated with dolutegravir q12h plus boosted darunavir along with directly observed treatment, and for the first time in 20 years, plasmatic viral load values are below 100 copies/mL., Conclusions: This case illustrates that the combination of E157Q and R263K plus M184V can be selected in vivo in a clinical scenario of poor adherence with BIC/FTC/TAF, although it is a very rare phenomenon. Previous VF with first-generation integrase strand transfer inhibitors (INSTIs) should be kept in mind when switching patients to second-generation INSTIs., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: Integrase strand transfer inhibitors (INSTIs) have been recently recommended as the preferred first-line option for antiretroviral treatment initiators in low- and middle-income countries (LMICs) in response to the growing circulation of resistant HIV to non-nucleoside reverse transcriptase inhibitors (NNRTIs). In this study, we estimated the frequency of pretreatment drug resistance (PDR) to INSTIs in West Africa and Southeast Asia., Materials and Methods: Using samples collected from 2015 to 2016, and previously used to assessed PI, NRTI and NNRTI resistance, we generated HIV integrase sequences and identified relevant INSTI PDR mutations using the Stanford and ANRS algorithms., Results: We generated 353 integrase sequences. INSTI PDR frequency was low, 1.1% (4/353) overall, ranging from 0% to 6.3% according to country. However, frequency of PDR to any drug class was very high, 17.9% (95% CI: 13.9%-22.3%), and mostly associated with a high level of NNRTI PDR, 9.7%, and a moderate level of NRTI PDR, 5.3%., Conclusions: Our results support the recent introduction of INSTIs in LMICs to improve treatment outcome in these settings, but also stress the need for effective actions to prevent uncontrolled emergence of drug resistance to this drug class., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Competing Interests: ALP receives grants from NIH, NHLBI, the EU (via the VERDI Consortium), Gilead, ViiV Healthcare, and Merck for commercial drug studies paid to the organisation NEAT ID; receives honoraria for educational talks and advisory board membership from Gilead, ViiV Healthcare, Merck, and Virology Education; is on a data safety monitoring board for MRC–PENTA studies; is a member of the EACS and BHIVA HIV treatment guidelines panels; is the President of NEAT ID; and is a board member of CUAMM UK. WDFV receives grants from the Bill & Melinda Gates Foundation, SA Medical Research Council, NIH, Unitaid, Foundation for Innovative New Diagnostics, Children's Investment Fund Foundation, USAID, ViiV Healthcare, and Merck, paid to the institution; receives drug donations from Gilead, ViiV Healthcare, Merck, and Johnson & Johnson; does commercial drug studies for Merck and Novo; receives honoraria for educational talks and advisory board membership for Gilead, ViiV Healthcare, Mylan–Viatris, Merck, Adcock-Ingram, Aspen, Abbott, Roche, Johnson & Johnson, Sanofi, and Virology Education; and is a member of the International NIH HIV data safety monitoring board and WHO and SAHCS HIV guideline committees.

Background: Tackling HIV drug resistance is one of major challenges for ending AIDS epidemic, but the elevated expense of cutting-edge genomics hampers the advancement of HIV genotype testing for clinical care., Methods: We developed a HIV genotype testing pipeline that centers on a cost-efficient portable Nanopore sequencer. Accuracy verification was conducted through comparison with parallel data obtained via fixed-site Pacbio sequencing. Our complete pol-gene sequencing strategy coupled with portable high-throughput sequencing was applied to identify drug resistance mutations across 58 samples sourced from the ART-treated Los Angeles General Medical Center Rand Schrader Clinic (LARSC) cohort (7 samples from 7 individuals) and the ART-naïve Center for HIV/AIDS Vaccine Immunology (CHAVI) cohort (51 samples from 38 individuals)., Results: A total of 472 HIV consensus sequences, each tagged with a unique molecular identifier, were produced from over 1.4 million bases acquired through portable Nanopore sequencing, which matched those obtained independently via Pacbio sequencing. With this desirable accuracy, we first documented the linkage of multidrug cross-resistance mutations across Integrase Strand Transfer inhibitors (INSTIs) and Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) from an individual failing a second-generation INSTI regimen. By producing more than 500 full-length HIV pol gene sequences in a single portable sequencing run, we detected Protease Inhibitor (PI), Nucleoside Reverse Transcriptase Inhibitor (NRTI), NNRTI and INSTI resistance mutations. All drug resistance mutations identified through portable sequencing were cross-validated using fixed-site Pacbio sequencing., Conclusions: Our accurate and affordable HIV drug resistance testing solution is adaptable for both individual patient care and large-scale surveillance initiatives., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

HIV-1 integrase (IN) is an important molecular target for the development of anti-AIDS drugs. A recently FDA-approved second-generation integrase strand transfer inhibitor (INSTI) cabotegravir (CAB, 2021) is being marketed for use in long-duration antiviral formulations. However, missed doses during extended therapy can potentially result in persistent low levels of CAB that could select for resistant mutant forms of IN, leading to virological failure. We report a series of N -substituted bicyclic carbamoyl pyridones (BiCAPs) that are simplified analogs of CAB. Several of these potently inhibit wild-type HIV-1 in single-round infection assays in cultured cells and retain high inhibitory potencies against a panel of viral constructs carrying resistant mutant forms of IN. Our lead compound, 7c , proved to be more potent than CAB against the therapeutically important resistant double mutants E138K/Q148K (>12-fold relative to CAB) and G140S/Q148R (>36-fold relative to CAB). A significant number of the BiCAPs also potently inhibit the drug-resistant IN mutant R263K, which has proven to be problematic for the FDA-approved second-generation INSTIs.

Structural organization of HIV-1 integrase is based on a tetramer formed by two protein dimers. Within this tetramer, the catalytic domain of one subunit of the first dimer interacts with the N-terminal domain of the second dimer subunit. It is the tetrameric structure that allows both ends of the viral DNA to be correctly positioned relative to the cellular DNA and to realize catalytic functions of integrase, namely 3'-processing and strand transfer. However, during the HIV-1 replicative cycle, integrase is responsible not only for the integration stage, it is also involved in reverse transcription and is necessary at the stage of capsid formation of the newly formed virions. It has been suggested that HIV-1 integrase is a structurally dynamic protein and its biological functions depend on its structure. Accordingly, studying interactions between the domains of integrase that provide its tetrameric structure is important for understanding its multiple functions. In this work, we investigated the role of three amino acids of the catalytic domain, I182, R187, and K188, located in the contact region of two integrase dimers in the tetramer structure, in reverse transcription and integration. It has been shown that the R187 residue is extremely important for formation of the correct integrase structure, which is necessary at all stages of its functional activity. The I182 residue is necessary for successful integration and is not important for reverse transcription, while the K188 residue, on the contrary, is involved in formation of the integrase structure, which is important for the effective reverse transcription.

People living with human immunodeficiency virus (HIV) receiving integrase strand transfer inhibitors (INSTIs) have been reported to experience virological failure in the absence of resistance mutations in integrase. To elucidate INSTI resistance mechanisms, we propagated HIV-1 in the presence of escalating concentrations of the INSTI dolutegravir. HIV-1 became resistant to dolutegravir by sequentially acquiring mutations in the envelope glycoprotein (Env) and the nucleocapsid protein. The selected Env mutations enhance the ability of the virus to spread via cell-cell transfer, thereby increasing the multiplicity of infection (MOI). While the selected Env mutations confer broad resistance to multiple classes of antiretrovirals, the fold resistance is ~2 logs higher for INSTIs than for other classes of drugs. We demonstrate that INSTIs are more readily overwhelmed by high MOI than other classes of antiretrovirals. Our findings advance the understanding of how HIV-1 can evolve resistance to antiretrovirals, including the potent INSTIs, in the absence of drug-target gene mutations.

The first- and second-generation clinically used HIV-1 integrase (IN) strand transfer inhibitors (INSTIs) are key components of antiretroviral therapy (ART), which work by blocking the integration step in the HIV-1 replication cycle that is catalyzed by a nucleoprotein assembly called an intasome. However, resistance to even the latest clinically used INSTIs is beginning to emerge. Developmental third-generation INSTIs, based on naphthyridine scaffolds, are promising candidates to combat drug-resistant viral variants. Among these novel INSTIs, compound 4f exhibits two distinct conformations when binding with intasomes from HIV-1 and the closely related prototype foamy virus (PFV) despite the high structural similarity of their INSTI binding pockets. The molecular mechanism and the key active site residues responsible for these differing binding modes in closely related intasomes remain elusive. To unravel the molecular determinants governing the two distinct binding modes, we applied a novel molecular dynamics-based free energy method that utilizes alchemical pathways to overcome the sampling challenges associated with transitioning between the two bound conformations of ligand 4f within the crowded environments of the INSTI binding pockets in these intasomes. The calculated conformational free energies successfully recapitulate the experimentally observed binding mode preferences in the two viral intasomes. Analysis of the simulated structures suggests that the observed binding mode preferences are caused by amino acid residue differences in both the front and the central catalytic sub-pocket of the INSTI binding site in HIV-1 and PFV. Additional free energy calculations on mutants of HIV-1 and PFV revealed that while both sub-pockets contribute to binding mode selection, the central sub-pocket plays a more important role. These results highlight the importance of both side chain and solvent reorganization, as well as the conformational entropy in determining the ligand binding mode, and will help inform the development of more effective INSTIs for combatting drug-resistant viral variants.

After a decade of dolutegravir (DTG) use in various antiretroviral therapy combinations and in diverse populations globally, it is critical to identify HIV strains with reduced drug susceptibility and monitor emergent resistance in people living with HIV who experience virologic failure while on DTG-based regimens. We searched the PubMed, Embase, and Cochrane databases to identify studies that reported DTG resistance-associated mutations (RAMs) emerging under selection pressure. Our review showed that RAMs conferring resistance to DTG were rare in 2-drug and 3-drug regimens used in real-world cohorts, corroborating data from clinical trials. The potency of DTG in maintaining virologic suppression was demonstrated, even in cases of pre-existing resistance to companion drugs in the regimen. Estimates of DTG RAMs depended on the population and certain risk factors, including monotherapy, baseline resistance or lack of genotypic testing, treatment history and prior virologic failure, and suboptimal treatment adherence. The RAMs detected after virologic failure, often in heavily treatment-experienced individuals with prior exposure to integrase strand transfer inhibitors, were G118R, E138K, G140A/C/R/S, Q148H/K/R, N155H, and R263K. Overall, these data highlight the durable effectiveness and high barrier to resistance of DTG as part of combination antiretroviral therapy in a wide variety of settings.

In this study, we examined the occurrence of acquired and transmitted drug resistance to integrase strand transfer inhibitor (INSTI) in HIV-1 strains in Chongqing (China) for guiding for the routine testing of INSTI-associated HIV-1 genotype resistance. Plasma samples were obtained from HIV-1 patients at Chongqing Public Health Medical Center from July 2019 to August 2022. Besides, amplification, sequence, and analysis of the portion of the HIV-1 pol gene that encodes the integrase protein were implemented to identify INSTI resistance. Integrase sequence data was harvested for a comprehensive cohort of 1032 patients infected with HIV-1. This cohort consisted of 564 ART-naive patients, 465 ART-treated patients, and 3 patients with an unknown treatment history. Within the study group, we identified INSTI resistance in 21 patients (2.03%, 21/1032), including 17 ART-treated patients (3.66%, 17/465). Among the ART-treated patients, 12 were INSTI-treated (11.76%, 12/102), 5 were INSTI-naive (1.38%, 5/363), and 4 were ART-ineffective patients (0.71%, 4/564). The prevalent major resistance mutation was Q148R (0.48%, 5/1032), while the most prevalent accessory resistance mutation was E157Q (1.65%, 17/1032). In light of the above, it is recommended that the incidence of accessory genotype analysis should be considered before starting any future INSTI-based therapy, especially in patients with drug resistance to NRTIs and NNRTIs and the reduction of INSTI sensitivity should be carefully monitored and investigated. Regular monitoring for resistance should be implemented after the use of INSTIs, and, importantly, ongoing monitoring of the decreasing susceptibility to INSTIs is crucial following the initiation of treatment with INSTIs.

Background: Integrase strand transfer inhibitors (INSTIs) are recommended as first-line ART for people living with HIV (PLWH) in most guidelines. The INSTI-resistance-associated mutation E157Q, a highly prevalent (2%-5%) polymorphism of the HIV-1 (human immunodeficiency virus type 1) integrase gene, has limited data on optimal first-line ART regimens. We assessed the virological outcomes of various first-line ART regimens in PLWH with E157Q in real-world settings., Methods: A multicentre retrospective observational study was conducted on PLWH who underwent integrase genotypic drug-resistance testing before ART initiation between 2008 and 2019 and were found to have E157Q. Viral suppression (<50 copies/mL) rate at 24 and 48 weeks, time to viral suppression and time to viral rebound (≥100 copies/mL) were compared among the first-line ART regimens., Results: E157Q was detected in 167 (4.1%) of 4043 ART-naïve PLWH. Among them, 144 had available clinical data after ART initiation with a median follow-up of 1888 days. Forty-five started protease inhibitors + 2 NRTIs (PI group), 33 started first-generation INSTI (raltegravir or elvitegravir/cobicistat) + 2 NRTIs (INSTI-1 group), 58 started once-daily second-generation INSTI (dolutegravir or bictegravir) + 2 NRTIs (INSTI-2 group) and eight started other regimens. In the multivariate analysis, the INSTI-2 group showed similar or favourable outcomes compared with the PI group for viral suppression rates, time to viral suppression and time to viral rebound. Two cases in the INSTI-1 group experienced virological failure., Conclusions: The general guideline recommendation of second-generation INSTI-based first-line ART for most PLWH is also applicable to PLWH harbouring E157Q., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Transmitted Resistance exists in a newly diagnosed person who has not yet started their treatment. Our objective was to obtain a profile of HIV-1 resistance to integrase inhibitors in newly diagnosed treatment-naïve patients. Fifty people newly diagnosed with HIV-1 infection who had never received antiretroviral treatment were recruited. The complete integrase gene was amplified by nested RTPCR and the sequences obtained were analyzed with the ReCall and HIVdb v9.0. The overall prevalence transmitted due to mutations with some impact on integrase strand transfer inhibitors (INSTI) activity during the study period was 8%. The major E138K mutation was detected in only 1 patient and the secondary G163R mutation was detected in the other 3. The transmitted resistance for the first generation INSTI was 8% and for the second generation it was 0%. In Chile the resistance transmitted to INSTI is low and it is in according values detect in other part of the world., Competing Interests: Declaration of Competing Interest The authors report no conflicts of interest relevant to this article., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Integrase strand-transfer inhibitors (INSTIs) are associated with weight gain in women living with HIV (WLH). Relationships between drug exposure, baseline obesity, and INSTI-associated weight gain remain unclear. Data from 2006 to 2016 were analyzed from virally suppressed WLH enrolled in the Women's Interagency HIV Study, who switched/added an INSTI to antiretroviral therapy: [raltegravir (RAL), dolutegravir (DTG), or elvitegravir (EVG)]. Percent body weight change was calculated from weights obtained a median 6 months pre-INSTI and 14 months post-INSTI initiation. Hair concentrations were measured with validated liquid chromatography-mass spectrometry (MS)/MS assays. Baseline (preswitch) weight status evaluated obese (body mass index, BMI, ≥30 kg/m 2 ) versus nonobese (BMI <30 kg/m 2 ). Mixed models examined the drug hair concentration*baseline obesity status interaction for each INSTI. There were 169 WLH included: 53 (31%) switched to RAL, 72 (43%) to DTG, and 44 (26%) to EVG. Women were median age 47-52 years, predominantly Non-Hispanic Black, median CD4 counts >500 cells/mm 3 , >75% with undetectable HIV-1 RNA. Over ∼1 year, women experienced median increases in body weight: 1.71% (-1.78, 5.00) with RAL; 2.40% (-2.82, 6.50) with EVG; and 2.48% (-3.60, 7.88) with DTG. Baseline obesity status modified the relationship between hair concentrations and percent weight change for DTG and RAL ( p' s < 0.05): higher DTG, yet lower RAL concentrations were associated with greater weight gain among nonobese women. Additional pharmacologic assessments are needed to understand the role of drug exposure in INSTI-associated weight gain.

The presence of human immunodeficiency virus (HIV) 1 subtype A6, characterized by the L74I integrase (IN) polymorphism, is associated with confirmed virologic failure in clinical trials of long-acting cabotegravir and rilpivirine. We investigated the effect of L74I on replication capacity (RC) of recombinant viruses carrying this polymorphism in combination with various IN stand-transfer inhibitor resistance mutations. The presence of L74I conferred greater RC to recombinant viruses expressing HIV-1 A6 IN when present together with G118R, G140R, Q148H, and R263K; no significant difference in RC was observed for the Q148K or R mutants. These findings may explain, in part, the association of HIV-1 subtype A6 with virologic failure., Competing Interests: Potential conflicts of interest. J. L. J. is an employee of ViiV and may hold stock in GlaxoSmithKline. D. R. K. has received consulting honoraria, research support, and/or speaker fees from AbbVie, Gilead, GlaxoSmithKline, Janssen, Roche, and ViiV. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

HIV-1 infection depends on the integration of viral DNA into host chromatin. Integration is mediated by the viral enzyme integrase and is blocked by integrase strand transfer inhibitors (INSTIs), first-line antiretroviral therapeutics widely used in the clinic. Resistance to even the best INSTIs is a problem, and the mechanisms of resistance are poorly understood. Here, we analyze combinations of the mutations E138K, G140A/S, and Q148H/K/R, which confer resistance to INSTIs. The investigational drug 4d more effectively inhibited the mutants compared with the approved drug Dolutegravir (DTG). We present 11 new cryo-EM structures of drug-resistant HIV-1 intasomes bound to DTG or 4d, with better than 3-Å resolution. These structures, complemented with free energy simulations, virology, and enzymology, explain the mechanisms of DTG resistance involving E138K + G140A/S + Q148H/K/R and show why 4d maintains potency better than DTG. These data establish a foundation for further development of INSTIs that potently inhibit resistant forms in integrase.

Nuclear localization signal (NLS) of HIV-1 integrase (IN) is implicated in nuclear import of HIV-1 preintegration complex (PIC). Here, we established a multiclass drug-resistant HIV-1 variant (HIV KGD ) by consecutively exposing an HIV-1 variant to various antiretroviral agents including IN strand transfer inhibitors (INSTIs). HIV KGD was extremely susceptible to a previously reported HIV-1 protease inhibitor, GRL-142, with IC 50 of 130 femtomolar. When cells were exposed to HIV KGD IN-containing recombinant HIV in the presence of GRL-142, significant decrease of unintegrated 2-LTR circular cDNA was observed, suggesting that nuclear import of PIC was severely compromised by GRL-142. X-ray crystallographic analyses revealed that GRL-142 interacts with NLS's putative sequence (DQAEHLK) and sterically blocks the nuclear transport of GRL-142-bound HIV KGD 's PIC. Highly INSTI-resistant HIV-1 variants isolated from heavily INSTI-experienced patients proved to be susceptible to GRL-142, suggesting that NLS-targeting agents would serve as salvage therapy agents for highly INSTI-resistant variant-harboring individuals. The data should offer a new modality to block HIV-1 infectivity and replication and shed light on developing NLS inhibitors for AIDS therapy.

Objectives: In Eastern Europe, HIV-1 transmitted drug resistance (TDR) data, especially in the integrase (IN) region, are limited. In Estonia, INSTI (integrase strand transfer inhibitors) TDR has been studied only prior to the INSTI scale-up in late 2010s. The current study aimed to determine the levels of protease (PR), reverse transcriptase (RT) and IN surveillance drug resistance mutations (SDRMs) among newly diagnosed patients in Estonia in 2017., Methods: The study included 216 newly diagnosed HIV-1 individuals from 1 January until 31 December 2017 in Estonia. Demographic and clinical data were obtained from the Estonian Health Board, the Estonian HIV Cohort Study (E-HIV) and clinical laboratories' databases. The PR-RT and IN regions were sequenced and analysed for SDRMs and subtype determination., Results: Seventy-one percent (151/213) of available HIV-positive samples were successfully sequenced. The overall level of TDR was 7.9% (12/151; 95% CI 4.4%-13.8%); no dual or triple class resistance was detected. No major INSTI mutations were found. The distribution of SDRMs for NNRTI, NRTI and PI was 5.9% (9/151), 1.3% (2/151) and 0.7% (1/151), respectively. The predominant NNRTI mutation was K103N. CRF06&#95;cpx was the predominant variant (59%) in the Estonian HIV-1 population, followed by subtype A (9%) and subtype B (8%)., Conclusion: Although no major INSTI mutations were found, close monitoring of INSTI SDRMs is needed considering the extensive use of the first- and second-generation INSTIs. PR-RT TDR is slowly rising in Estonia, indicating the need for continuous surveillance in the future. Low genetic barrier NNRTIs should be avoided in the treatment regimens., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: This work aims to evaluate integrase resistance and its predictors in HIV-1 infected combined antiretroviral therapy (cART) experienced individuals failing a dolutegravir-based regimen., Methods: Major resistance mutations (MRM) and genotypic susceptibility score (GSS) of dolutegravir companion drugs were evaluated on plasma genotypic resistance test (GRT) performed at dolutegravir failure. Logistic regression was used to evaluate factors associated to the risk of integrase strand-transfer inhibitors (INSTI)-resistance at dolutegravir failure., Results: We retrospectively analysed 467 individuals. At failure GRT, individuals had been under dolutegravir for a median (IQR) time of 11 (5-20) months; around half of them had never been exposed to INSTI (52%) and 10.7% were at first-line regimen. Fifty-eight (12.4%) individuals showed ≥1 INSTI MRM. Among them, people INSTI-exposed showed significantly higher prevalence of INSTI resistance compared to those who were INSTI naïve [46 (21.2%) versus 9 (3.9%), P < 0.001].N155H was the most prevalent MRM (5.4%), followed by G140S (4.5%) and Q148H (4.3%). These MRM were more probably present in INSTI-experienced individuals compared to those INSTI naïve. Despite failure, 89.5% of individuals harboured viral strains fully susceptible to dolutegravir and bictegravir and 85.0% to all INSTI. No INSTI exposure before receiving dolutegravir [OR: 0.35 (0.16-0.78), P < 0.010] and a GSS for companion drugs ≥2 (OR: 0.09 [0.04-0.23], P < 0.001) were negatively associated with INSTI resistance at failure., Conclusions: In a large set of individuals failing dolutegravir in real-life, INSTI resistance was low and mainly related to previous first-generation INSTI exposure. Surveillance of integrase resistance remains crucial to preserve efficacy of INSTI class in the future., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Human immunodeficiency virus (HIV) treatment with antiretroviral regimens containing integrase strand transfer inhibitors such as dolutegravir (DTG) and bictegravir (BIC) offers high levels of protection against the development of drug resistance mutations. Despite this, resistance to DTG and BIC can occur through the development of the R263K integrase substitution. Failure with DTG has also been associated with the emergence of the G118R substitution. G118R and R263K are usually found separately but have been reported together in highly treatment-experienced persons who experienced treatment failure with DTG. We used cell-free strand transfer and DNA binding assays and cell-based infectivity, replicative capacity, and resistance assays to characterize the G118R plus R263K combination of integrase mutations. R263K reduced DTG and BIC susceptibility ~2-fold, in agreement with our previous work. Single-cycle infectivity assays showed that G118R and G118R plus R263K conferred ~10-fold resistance to DTG. G118R alone conferred low levels of resistance to BIC (3.9-fold). However, the G118R plus R263K combination conferred high levels of resistance to BIC (33.7-fold), likely precluding the use of BIC after DTG failure with the G118R plus R263K combination. DNA binding, viral infectivity, and replicative capacity of the double mutant were further impaired, compared to single mutants. We propose that impaired fitness helps to explain the scarcity of the G118R plus R263K combination of integrase substitutions in clinical settings and that immunodeficiency likely contributes to its development., Competing Interests: The authors declare no conflict of interest.

Background: We evaluated the prevalence of transmitted drug resistance (TDR) to integrase strand-transfer inhibitors (INSTIs) and nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and of clinically relevant resistance (CRR) in newly diagnosed people with human immunodeficiency virus (HIV; PWH) naive to antiretroviral therapy (ART) in Europe., Methods: MeditRes is a consortium that includes ART-naive PWH newly diagnosed in France, Greece, Italy, Portugal, and Spain during 2018-2021. Reverse transcriptase and INSTI sequences were provided by participating centers. To evaluate the prevalence of surveillance drug resistance mutations (SDRM), we used the calibrated population resistance tools from the Stanford HIV website. To evaluate CRR, defined as any resistance level ≥3, we used the Stanford HIV Drug Resistance Database v.9.1 algorithm., Results: We included 2705 PWH, 72% men, median age of 37 years (interquartile range, 30-48); 43.7% were infected by non-B subtypes. The prevalence of INSTI-SDRMs was 0.30% (T66I, T66A, E92Q, E138T, E138K, Y143R, S147G, R263K; all n=1) and the prevalence of NRTI-SDRMs was 5.77% (M184V: 0.85%; M184I: 0.18%; K65R/N: 0.11%; K70E: 0.07%; L74V/I: 0.18%; any thymidine analog mutations: 4.36%). INSTI-CRR was 2.33% (0.15% dolutegravir/bictegravir, 2.29% raltegravir/elvitegravir) and 1.74% to first-line NRTIs (0.89% tenofovir/tenofovir alafenamide, 1.74% abacavir, 1.07% lamivudine/emtricitabine)., Conclusions: We present the most recent data on TDR to integrase-based first-line regimens in Europe. Given the low prevalence of CRR to second-generation integrase inhibitors and to first-line NRTIs during 2018-2021, it is unlikely that newly diagnosed PWH in MeditRes countries would present with baseline resistance to a first-line regimen based on second-generation integrase inhibitors., Competing Interests: Potential conflicts of interest. E. T. has received funds for attending meetings and/or travel from Moderna. C. C. has received grants or contracts from ViiV Healthcare, Gilead, and Merck Sharp & Dohme and support for attending meetings and/or travel from Gilead and Merck Sharp & Dohme. A. de M. has received payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from ViiV Healthcare and Gilead and support for attending meetings and/or travel from ViiV Healthcare. K. S. has received funds for attending symposia, speaking, organizing educational activities, and travel grants from Gilead Sciences and ViiV Healthcare. A. A. has received support and travel support paid to author from Gilead and AbbVie and payment for lectures, presentations, speakers bureaus, manuscript writing, or educational events paid to author from Roche Diagnostics, Vircell, and Gilead. R. D. has received consulting fees for advisory board membership paid to author from GSK, and Hologic and payment or honoraria for lectures from GSK, ViiV Healthcare, Gilead, and Merck Sharp & Dohme. S. L.-N. has received funds for attending symposia, speaking, organizing educational activities, and travel grants from Gilead Sciences, Merck Sharp & Dohme, and ViiV Healthcare. P. G. has received payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Gilead, Merck Sharp & Dohme, and ViiV Healthcare; support for attending meetings and/or travel from Merck Sharp & Dohme and ViiV Healthcare; and support for participation on a data and safety monitoring board (DSMB) or advisory board from ViiV Healthcare. D. P. has received funds for attending meetings and/or travel from Moderna. M. M. S. has received payment to author for lectures, presentations, speakers bureaus, manuscript writing, or educational events from ViiV Healthcare and for participation on a DSMB or advisory board from ViiV Healthcare, Janssen-Cilag, and Theratechnologies. F. C.-S. has received grants or contracts paid to institution and/or collaborating partner from Gilead Sciences, Merck Sharp & Dohme, and ViiV Healthcare; consulting fees to author from Gilead Sciences, Merck Sharp & Dohme, Theratechnologies, and ViiV Healthcare; and payment or honoraria to author for lectures, presentations, speakers bureaus, manuscript writing, or educational events from AbbVie, Gilead Sciences, Janssen-Cilag, Merck Sharp & Dohme, and ViiV Healthcare. A.-G. M. has received support for attending meetings and/or travel from Gilead Sciences and speaking and research grants from ViiV Healthcare, Gilead Sciences, and Merck Sharp & Dohme. F. G. has received grants or contracts from Gilead, AbbVie, Roche, and Seegene; consulting fees from Gilead, ViiV Healthcare, AbbVie, and Thera; payment or honoraria for speaking from Gilead, ViiV Healthcare, AbbVie, Thera, Merck Sharp & Dohme, and Roche; and support for attending symposia from Gilead, AbbVie, and Vircell. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed. Data availability. Data are available to investigators upon reasonable request., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

With the widespread use of Integrase strand transfer inhibitors (INSTIs), surveillance of HIV-1 pretreatment drug resistance is critical in optimizing antiretroviral treatment efficacy. However, despite the introduction of these drugs, data concerning their resistance mutations (RMs) is still limited in Ethiopia. Thus, this study aimed to assess INSTI RMs and polymorphisms at the gene locus coding for Integrase (IN) among viral isolates from ART-naive HIV-1 infected Ethiopian population. This was a cross-sectional study involving isolation of HIV-1 from plasma of 49 newly diagnosed drug-naive HIV-1 infected individuals in Addis-Ababa during the period between June to December 2018. The IN region covering the first 263 codons of blood samples was amplified and sequenced using an in-house assay. INSTIs RMs were examined using calibrated population resistance tool version 8.0 from Stanford HIV drug resistance database while both REGA version 3 online HIV-1 subtyping tool and the jumping profile Hidden Markov Model from GOBICS were used to examine HIV-1 genetic diversity. Among the 49 study participants, 1 (1/49; 2%) harbored a major INSTIs RM (R263K). In addition, blood specimens from 14 (14/49; 28.5%) patients had accessory mutations. Among these, the M50I accessory mutation was observed in a highest frequency (13/49; 28.3%) followed by L74I (1/49; 2%), S119R (1/49; 2%), and S230N (1/49; 2%). Concerning HIV-1 subtype distribution, all the entire study subjects were detected to harbor HIV-1C strain as per the IN gene analysis. This study showed that the level of primary HIV-1 drug resistance to INSTIs is still low in Ethiopia reflecting the cumulative natural occurrence of these mutations in the absence of selective drug pressure and supports the use of INSTIs in the country. However, continues monitoring of drug resistance should be enhanced since the virus potentially develop resistance to this drug classes as time goes by., (© 2023. The Author(s).)

Competing Interests: The authors have no funding or conflicts of interest to disclose.

Transmissions of simian viruses to humans has originated the different groups of HIV-1. We recently identified a functional motif (CLA), in the C-terminal domain of the integrase, essential for integration in HIV-1 group M. Here, we found that the motif is instead dispensable in group O isolates, because of the presence, in the N-terminal domain of HIV-1 O of a specific sequence, Q7G27P41H44, that we define as the NOG motif. Alterations of reverse transcription and of 3' processing observed by mutating the CLA motif of IN M are fully rescued to wt levels by inserting the sequence of the NOG motif in the N-ter of the protein. These results indicate that the two motifs (CLA and NOG) functionally complement each other and a working model accounting for these observations is proposed. The establishment of these two alternative motifs seems to be due to the different phylogenetic origin and history of these two groups. Indeed, the NOG motif is already present in the ancestor of group O (SIVgor) while it is absent from SIVcpzPtt, the ancestor of group M. The CLA motif, instead, seems to have emerged after SIVcpzPtt has been transferred to humans, since no conservation is found at the same positions in these simian viruses. These results show the existence of two-group specific motifs in HIV-1 M and O integrases. In each group, only one of the motifs is functional, potentially leading the other motif to diverge from its original function and, in an evolutionary perspective, assist other functions of the protein, further increasing HIV genetic diversity., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Toccafondi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

AIDS (Acquired immunodeficiency syndrome) is one of the chronic and potentially life-threatening epidemics across the world. Hitherto, the non-existence of definitive drugs that could completely cure the Human immunodeficiency virus (HIV) implies an urgent necessity for the discovery of novel anti-HIV agents. Since integration is the most crucial stage in retroviral replication, hindering it can inhibit overall viral transmission. The 5 FDA-approved integrase inhibitors were computationally investigated, especially owing to the rising multiple mutations against their susceptibility. This comparative study will open new possibilities to guide the rational design of novel lead compounds for antiretroviral therapies (ARTs), more specifically the structure-based design of novel Integrase strand transfer inhibitors (INSTIs) that may possess a better resistance profile than present drugs. Further, we have discussed potent anti-HIV natural compounds and their interactions as an alternative approach, recommending the urgent need to tap into the rich vein of indigenous knowledge for reverse pharmacology. Moreover, herein, we discuss existing evidence that might change in the near future., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

HIV integrase (IN) inserts viral DNA into the host genome and is the target of the strand transfer inhibitors (STIs), a class of small molecules currently in clinical use. Another potent class of antivirals is the allosteric inhibitors of integrase, or ALLINIs. ALLINIs promote IN aggregation by stabilizing an interaction between the catalytic core domain (CCD) and carboxy-terminal domain (CTD) that undermines viral particle formation in late replication. Ongoing challenges with inhibitor potency, toxicity, and viral resistance motivate research to understand their mechanism. Here, we report a 2.93 Å X-ray crystal structure of the minimal ternary complex between CCD, CTD, and the ALLINI BI-224436. This structure reveals an asymmetric ternary complex with a prominent network of π-mediated interactions that suggest specific avenues for future ALLINI development and optimization., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Eilers et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Despite the scale-up of ART and the rollout in Tanzania of dolutegravir, an integrase strand transfer inhibitor (INSTI), treatment success has not been fully realized. HIV drug resistance (HIVDR), including dolutegravir resistance, could be implicated in the notable suboptimal viral load (VL) suppression among HIV patients., Objectives: To determine the prevalence and patterns of acquired drug resistance mutations (DRMs) among children and adults in Tanzania., Methods: A national cross-sectional HIVDR survey was conducted among 866 children and 1173 adults. Genotyping was done on dried blood spot and/or plasma of participants with high HIV VL (≥1000 copies/mL). HIV genes (reverse transcriptase, protease and integrase) were amplified by PCR and directly sequenced. The Stanford HIVDR Database was used for HIVDR interpretation., Results: HIVDR genotyping was performed on blood samples from 137 participants (92 children and 45 adults) with VL ≥ 1000 copies/mL. The overall prevalence of HIV DRMs was 71.5%, with DRMs present in 78.3% of children and 57.8% of adults. Importantly, 5.8% of participants had INSTI DRMs including major DRMs: Q148K, E138K, G118R, G140A, T66A and R263K. NNRTI, NRTI and PI DRMs were also detected in 62.8%, 44.5% and 8% of participants, respectively. All the participants with major INSTI DRMs harboured DRMs targeting NRTI backbone drugs., Conclusions: More than 7 in 10 patients with high HIV viraemia in Tanzania have DRMs. The early emergence of dolutegravir resistance is of concern for the efficacy of the Tanzanian ART programme., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Abstract: Effectiveness of anti-HIV in the prevention of perinatal transmission has been established. Assessing the tolerance of drug exposure during pregnancy is of the utmost importance given the number of children exposed. HIV integrase and the recombinase-activating gene enzyme involved in the establishment of the T-lymphocyte repertoire show structural similarity. The inhibition of recombinase-activating (RAG) gene by anti-integrases is observed in vitro, in a variable way according to the molecules. Here, we show that in utero exposure to raltegravir did not alter the T-lymphocyte repertoire of 12 newborns. These reassuring data merit verification for other anti-integrases. ( ClinicalTrial.org NCT04024150)., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Integrase inhibitors (INIs) are a potent option for HIV treatment. Limited data exist on INI resistance in West Africa, particularly in children living with HIV/AIDS. We determined the prevalence of integrase gene polymorphisms and the frequency of naturally occurring amino acid (aa) substitutions at positions associated with INI resistance. Dried blood spot (DBS) samples were obtained from one hundred and seven (107) HIV-1-infected children aged less than 15 years old in two West African countries, Benin and Mali. All children were naïve to INI treatment, 56 were naïve to anti-retroviral therapy (ART), and 51 had received ART. Genetic sequencing of HIV integrase was successful in 75 samples. The aa changes at integrase positions associated with INI resistance were examined according to the Stanford HIV Genotypic Resistance database. The median ages were 2.6 and 10 years for ART-naïve and -treated children, respectively. The most common subtypes observed were CRF02&#95;AG (74.7%) followed by CRF06&#95;cpx (20%). No major INI-resistance mutations at positions 66, 92, 121, 143, 147, 148, 155, and 263 were detected. The most prevalent INI accessory resistance mutations were: L74I/M (14/75, 18.6%) followed by E157Q (8/75, 10.6%), G163E/N/T/Q (5/75, 6.6%), Q95A/H/P (2/75, 2.6%), and T97A (4/75, 5.3%). Other substitutions observed were M50I/L/P, H51E/P/S/Q, I72V, T112V, V201I, and T206S. Polymorphisms at positions which may influence the genetic barrier and/or drive the selection of specific INI-resistance pathways were detected. However, no transmitted drug resistance (TDR) to INI was detected among samples of INI-naïve patients. These findings support the use of this treatment class for children with HIV-1, particularly in West Africa.

Background: As use of dolutegravir (DTG) becomes more common in resource limited settings (RLS), the demand for integrase resistance testing is increasing. Affordable methods for genotyping all relevant HIV-1 pol genes (i.e., protease (PR), reverse transcriptase (RT) and integrase (IN)) are required to guide choice of future antiretroviral therapy (ART). We designed an in-house HIV-1 drug resistance (HIVDR) genotyping method that is affordable and suitable for use in RLS., Methods: We obtained remnant plasma samples from CAPRISA 103 study and amplified HIV-1 PR, RT and IN genes, using an innovative PCR assay. We validated the assay using remnant plasma samples from an external quality assessment (EQA) programme. We genotyped samples by Sanger sequencing and assessed HIVDR mutations using the Stanford HIV drug resistance database. We compared drug resistance mutations with previous genotypes and calculated method cost-estimates., Results: From 96 samples processed, we obtained sequence data for 78 (81%), of which 75 (96%) had a least one HIVDR mutation, with no major-IN mutations observed. Only one sample had an E157Q INSTI-accessory mutation. When compared to previous genotypes, 18/78 (23%) had at least one discordant mutation, but only 2/78 (3%) resulted in different phenotypic predictions that could affect choice of subsequent regimen. All CAPRISA 103 study sequences were HIV-1C as confirmed by phylogenetic analysis. Of the 7 EQA samples, 4 were HIV-1C, 2 were HIV-1D, and 1 was HIV-1A. Genotypic resistance data generated using the IDR method were 100% concordant with EQA panel results. Overall genotyping cost per sample was estimated at ~ US$43-$US49, with a processing time of ~ 2 working days., Conclusions: We successfully designed an in-house HIVDR method that is suitable for genotyping HIV-1 PR, RT and IN genes, at an affordable cost and shorter turnaround time. This HIVDR genotyping method accommodates changes in ART regimens and will help to guide HIV-1 treatment decisions in RLS., (© 2023. The Author(s).)

Objectives: In recent years, integrase strand transfer inhibitor (INSTI)-containing regimens have been increasingly adopted in treatment for HIV/AIDS and promoted as non-occupational post-exposure prophylaxis in China. This study aims to describe the prevalence of resistance to integrase and drug resistance mutations (DRMs) among ART-naive patients in Shenzhen, China., Methods: Serum samples and demographic information were collected from newly reported ART-naive patients in Shenzhen in 2020. The study sequenced the coding sequence of the HIV-1 integrase gene and determined the DRMs.​., Results: In this study, 1682 newly reported cases were included and 1071 of them were successfully sequenced finally. The prevalence of primary drug resistance was 1.77%, with 19 samples showing varying degrees of resistance to INSTIs. The study detected six major DRMs in 16 individuals and eight accessory DRMs in 24 individuals. The prevalence of transmitted drug resistance (TDR) mutations was 1.21%, with five transmitted mutations detected in 13 individuals. The prevalence of drug resistance to raltegravir and elvitegravir was statistically higher than to bictegravir, cabotegravir and dolutegravir., Conclusions: The prevalence of INSTI resistance in Shenzhen in 2020 was relatively high. ​Continued surveillance for resistance to INSTIs is recommended and treatment regimens should be adopted based on the pattern of resistance to INSTIs. ​Dolutegravir or bictegravir is first recommended when considering INSTIs as treatment regimens., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

INI1/SMARCB1 is a host protein that interacts with HIV-1 integrase (IN) and influences multiple stages of viral replication. IN is a viral enzyme responsible for integration, and it also binds to HIV-1 genomic RNA. Recent studies from our laboratory demonstrated that IN-interacting Rpt1 (Repeat 1) domain of INI1 and TAR RNA region of HIV-1 genome both bind to the same residues and surface of IN C-terminal domain (CTD). Based on a series of analyses, we found that INI1-Rpt1 and TAR RNA structurally mimic each other and that IN mutants defective for binding to INI1 are also defective for binding to RNA and produce morphologically defective virions. The similarity of INI1-Rpt1 and TAR RNA in binding to IN was established by testing the binding of IN-CTD mutants with INI1-Rpt1 and TAR RNA using the Alpha assay. Here, I describe Alpha assay methods to compare the binding of INI1-Rpt1 protein and HIV-1 TAR RNA to IN-CTD and describe a three-component assay to demonstrate the competition between TAR RNA and INI1-Rpt1 to bind to IN., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

To ensure the long-term efficacy of dolutegravir (DTG), we evaluated the genotypic profile in viral reservoirs among patients on third-line (3L) antiretroviral therapy (ART) in Cameroon, according to prior exposure to raltegravir (RAL). A facility-based study was conducted from May through December 2021 among patients on 3L ART from HIV treatment centers in Yaoundé and Douala. Viral load was measured, and genotyping was performed on plasma RNA and proviral DNA. HIV-1 drug resistance mutations were interpreted using HIVdb.v9.1 and phylogeny analysis was performed using MEGA.v7, with P < 0.05 considered significant. Of the 12,093 patients on ART, 53 fully met our inclusion criteria. The median (IQR) age was 51 years (40 to 55 years), and the male/female ratio was 4/5. The median duration on integrase strand-transfer inhibitors (INSTI)-containing regimens was 18 months (12 to 32 months), and 15.09% (8/53) were exposed to RAL. The most administered 3L ART was TDF+3TC+DTG+DRV/r (33.96%, 18/53). Only 5.66% (3/53) had unsuppressed viremia (>1000 copies/mL). Resistance testing in proviral DNA was successful for 18/22 participants and revealed 1/18 patients (5.56%, in the RAL-arm) with archived mutations at major resistance positions (G140R and G163R). Five subtypes were identified, CRF02&#95;AG (12/18), CRF22&#95;01AE (3/18), A1 (1/18), G (1/18), and F2 (1/18). In Cameroon, 3L-experienced patients had a good virological response with a low level of archived mutations in the integrase. This finding underscored the use of DTG-containing ART for heavily treated patients in similar programmatic settings. However, patients with prior exposure to RAL should be closely monitored following a stratified or personalized approach to mitigate risks of INSTI-resistance, alongside pharmacovigilance. IMPORTANCE We described the analysis of the genotypes of the population within third-line antiviral therapy in Cameroon, with a focus on defining the effects of prior raltegravir (RAL) treatment and resistance mutations for current dolutegravir (DTG) treatment. While supporting the current transition to DTG-containing ART in resource-limited settings toward the achievement of the UNAIDS' goal of HIV elimination by 2030, our findings suggested that RAL-exposed patients may need a specific monitoring approach either in a stratified or personalized model of third-line ART to ensure the long-term success of DTG-containing regimens.

Background: The HPTN 083 trial demonstrated that long-acting cabotegravir (CAB-LA) was superior to tenofovir-disoproxil fumarate/emtricitabine for human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP). Integrase strand transfer inhibitor (INSTI) resistance-associated mutations (RAMs) were detected in some participants with HIV infection. We used a low viral load INSTI genotyping assay to evaluate the timing of emergence of INSTI RAMs and assessed whether HIV screening with a sensitive RNA assay would have detected HIV infection before INSTI resistance emerged., Methods: Single-genome sequencing to detect INSTI RAMs was performed for samples with viral loads <500 copies/mL from 5 participants with previously identified INSTI RAMs and 2 with no prior genotyping results., Results: Major INSTI RAMs were detected in all 7 cases. HIV RNA testing identified infection before major INSTI RAMs emerged in 4 cases and before additional major INSTI RAMs accumulated in 1 case. Most INSTI RAMs were detected early when the viral load was low and CAB concentration was high., Conclusions: When using CAB-LA PrEP, earlier detection of HIV infection with a sensitive RNA assay may allow for earlier treatment initiation with the potential to reduce INSTI resistance risk. Further studies are needed to evaluate the value and feasibility of HIV RNA testing with CAB-LA PrEP., Competing Interests: Potential conflicts of interest. R. J. L. has served on scientific advisory boards for Merck and has received honoraria from Roche and Janssen. A. R. and M. S. C. are employees of ViiV Healthcare. J. W. M. is a consultant to Gilead Sciences, owns shares of Abound Bio, Inc, and share options in Infectious Disease Connect. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Cabotegravir (CAB) is an integrase strand transfer inhibitor (INSTI) formulated as a long-acting injectable drug approved for pre-exposure prophylaxis and use with a long acting rilpivirine formulation for therapy in patients with virological suppression. However, there has been no comprehensive review of the genetic mechanisms of CAB resistance. Studies reporting the selection of drug resistance mutations (DRMs) by CAB and the results of in vitro CAB susceptibility testing were reviewed. The impact of integrase mutations on CAB susceptibility was assessed using regularized regression analysis. The most commonly selected mutations in the 24 persons developing virological failure while receiving CAB included Q148R (n = 15), N155H (n = 7), and E138K (n = 5). T97A, G118R, G140 A/R/S, and R263K each developed in 1-2 persons. With the exception of T97A, G118R, and G140 A/R, these DRMs were also selected in vitro while G140R was selected in the SIV macaque model. Although these DRMs are similar to those occurring in persons receiving the related INSTI dolutegravir, Q148R was more likely to occur with CAB while G118R and R263K were more likely to occur with dolutegravir. Regularized regression analysis identified 14 DRMs significantly associated with reduced CAB susceptibility including six primary DRMs which reduced susceptibility on their own including G118R, Q148 H/K/R, N155H, and R263K, and eight accessory DRMs including M50I, L74 F/M, T97A, E138K, and G140 A/C/S. Isolates with Q148 H/K/R in combination with L74M, E138 A/K, G140 A/S, and N155H often had >10-fold reduced CAB susceptibility. M50I, L74M, and T97A are polymorphic mutations that alone did not appear to increase the risk of virological failure in persons receiving a CAB-containing regimen. Careful patient screening is required to prevent CAB from being used during active virus replication. Close virological monitoring is required to minimize CAB exposure to active replication to prevent the emergence of DRMs associated with cross-resistance to other INSTIs., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objectives: We report a case of incomplete HIV-1 suppression on a dolutegravir, lamivudine, and abacavir single-tablet regimen with the emergence of the H51Y and G118R integrase resistance mutations., Methods: Integrase sequencing was performed retrospectively by Sanger and next-generation sequencing. Rates of emergence and decline of resistance mutations were calculated using next-generation sequencing data. Dolutegravir plasma concentrations were measured by ultra-performance liquid chromatography-tandem mass spectrometry. The effects of H51Y and G118R on infectivity, fitness, and susceptibility to dolutegravir were quantified using cell-based assays., Results: During periods of non-adherence to treatment, mutations were retrospectively documented only by next-generation sequencing. Misdiagnosis by Sanger sequencing was caused by the rapid decline of mutant strains within the retroviral population. This observation was also true for a M184V lamivudine-resistant reverse transcriptase mutation found in association with integrase mutations on single HIV genomes. Resistance rebound upon treatment re-initiation was swift (>8000 copies per day). Next-generation sequencing indicated cumulative adherence to treatment. Compared to WT HIV-1, relative infectivity was 73%, 38%, and 43%; relative fitness was 100%, 35%, and 10% for H51Y, G118R, and H51Y+G118R viruses, respectively. H51Y did not change the susceptibility to dolutegravir, but G188R and H51Y+G118R conferred 7- and 28-fold resistance, respectively., Conclusion: This case illustrates how poorly-fit drug-resistant viruses wax and wane alongside erratic treatment adherence and are easily misdiagnosed by Sanger sequencing. We recommend next-generation sequencing to improve the clinical management of incomplete virological suppression with dolutegravir., Competing Interests: Competing interests None declared, (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)