Treatment Emergent Dolutegravir Resistance Mutations in Individuals Naïve to HIV-1 Integrase Inhibitors: A Rapid Scoping Review

Predicted dolutegravir resistance in people living with HIV in South Africa during 2020-35: a modelling study

BACKGROUND

In response to increasing resistance to non-nucleoside reverse transcriptase inhibitors, millions of people living with HIV have switched to dolutegravir-based antiretroviral therapy, so understanding the possible emergence of dolutegravir resistance is essential. We aimed to predict how dolutegravir resistance in South Africa will change over time.

METHODS

For this modelling study, we used the Modelling Antiretroviral Drug Resistance in South Africa (MARISA) model, a deterministic compartmental model calibrated to reproduce the HIV-1 epidemic in South Africa from 2005 to 2035 using data from the International Epidemiology Databases to Evaluate AIDS collaboration and the literature. Key parameters for modelling dolutegravir-resistance evolution were acquisition rates of dolutegravir-resistance mutations, reversion rates of dolutegravir-resistance mutations, the effect of resistance to nucleoside reverse transcriptase inhibitors on dolutegravir-resistance acquisition, the effect of dolutegravir resistance on dolutegravir-treatment efficacy, the probability of transmitting dolutegravir drug-resistance mutations compared with the probability of transmitting wild-type HIV, and the proportion of people with virologic failure on dolutegravir-based antiretroviral therapy with detectable drug levels. Model outcomes were estimated transmitted dolutegravir resistance and estimated acquired dolutegravir resistance.

FINDINGS

We estimated a substantial increase in the number of individuals on dolutegravir-based antiretroviral therapy after its introduction in 2020, increasing from 0 to approximately 7 million people (7·08-7·15) living with HIV on dolutegravir in 2035. We estimated the proportion of people living with HIV with viral suppression (ie, viral load <1000 copies per mL) on dolutegravir-based antiretroviral therapy to be 93% (uncertainty range 92·2-94·3) in 2035. We estimated that acquired dolutegravir resistance in people living with HIV on failing dolutegravir-based antiretroviral therapy would increase rapidly, from 18·5% (uncertainty range 12·5-25·4) in 2023 to 41·7% (29·0-54·0) in 2035. For transmitted dolutegravir resistance, we estimated an increase from 0·1% (0·0-0·2) in 2023 to 5·0% (1·9-11·9) in 2035. We estimated that resistance-mitigation strategies involving rapid switching to protease-inhibitor-based antiretroviral therapy could effectively reduce the increase in acquired dolutegravir resistance and slow the increase in transmitted dolutegravir resistance.

INTERPRETATION

Although dolutegravir-based antiretroviral therapy maintains high virological suppression, acquired and transmitted dolutegravir resistance are likely to increase. This increase will likely be greater in settings where HIV RNA monitoring, genotypic-resistance testing, and options to switch antiretroviral therapy regimens are scarce.

FUNDING

US National Institutes of Health National Institute of Allergy and Infectious Diseases, Swiss National Science Foundation, and University of Zurich Research Priority Program Evolution in Action.

Major role of dolutegravir in the emergence of the S147G integrase resistance mutation

BACKGROUND

The S147G mutation is associated with high-level resistance to the integrase strand transfer inhibitor (INSTI) elvitegravir. In several poorly documented cases, it was also selected in patients on dolutegravir. Given the widespread use of dolutegravir, further studies of S147G are required.

METHODS

We consulted the HIV-1 resistance databases of French laboratories to identify all cases of S147G emergence. We collected immunological and virological parameters, history of treatment and INSTI resistance mutations. Mann-Whitney and Fisher's exact tests were performed.

RESULTS

We retrospectively identified 88 cases of S147G selection, from 2015 to 2022, in 22 laboratories. The most frequent HIV-1 subtypes were Clade B (55.7%) and CRF02_AG (21.6%). At the time of resistance genotyping, the median viral load was 5860 copies/mL (IQR 1011-24  525) and the median CD4 cell count was 412 cells/mm3 (228-560). S147G emerged on dolutegravir (48%), elvitegravir (36%) and raltegravir (10%) treatments. S147G was associated with a larger median number of other INSTI mutations on dolutegravir than on elvitegravir [3.0 (2.0-4.0) versus 2.0 (1.0-2.0); P = 0.0002] and was never observed with Q148H or G118R. On dolutegravir, S147G was associated principally with T97A (62%), N155H (59%), E138K (50%), L74I/M (38%) and Q148R (33%).

CONCLUSIONS

In this French study, S147G emerged principally in patients on dolutegravir regimens, in association with up to five other INSTI resistance mutations. This accumulation of mutations suggests a replicative advantage on HIV strains under dolutegravir selection pressure, suggesting that caution is required when interpreting dolutegravir resistance in the presence of such S147G resistance patterns, even in patients prescribed dolutegravir twice daily.

First Reported Case of Integrase Strand Transfer Inhibitor Resistance in Suriname: Unusual Drug Resistance Mutations Following Exposure to Dolutegravir

Contemporary ART as Dolutegravir (DTG) has significantly advanced antiretroviral therapy, but relatively few data are available on its impact on the emergence of HIV-1 drug resistance mutations (DRMs). Monitoring the emergence of INSTI-associated DRMs following the introduction of DTG in Suriname will provide general insight and guide national HIV treatment strategies. All people living with HIV (PLHIV) in Suriname, for whom an INSTI drug resistance test was requested between September 2019 and February 2024 (n = 20), were included. HIV-1 integrase gene sequences were determined using Sanger sequencing. INSTI-associated mutations were identified using the Stanford HIV Drug Resistance Database program. The majority of the participants (66.7%) harbored HIV-1 subtype B, and 33.3% were B-recombinant forms. In addition to the INSTI wildtype, a strain was revealed carrying E157EQ and one person harbored a highly INSTI-resistant strain (E138K, G140S, Q148H and N155H). The emergence of a highly INSTI-resistant HIV-1 strain in Suriname, with unusual mutations for ART-experienced PLHIV exposed to DTG as the only INSTI, accentuates the need for continuous monitoring of the emergence of INSTI drug resistance mutations, not only to enable timely interventions and optimized treatment outcomes for PLHIV, but also to steer the decision making for ART protocols, especially for second generation INSTIs.

Comparative Analyses of Antiviral Potencies of Second-Generation Integrase Strand Transfer Inhibitors (INSTIs) and the Developmental Compound 4d Against a Panel of Integrase Quadruple Mutants

Second-generation integrase strand transfer inhibitors (INSTIs) are strongly recommended for people living with HIV-1 (PLWH). The emergence of resistance to second-generation INSTIs has been infrequent and has not yet been a major issue in high-income countries. However, the delayed rollouts of these INSTIs in low- to middle-income countries during the COVID-19 pandemic combined with increased transmission of drug-resistant mutants worldwide are leading to an increase in INSTI resistance. Herein, we evaluated the antiviral potencies of our lead developmental INSTI 4d and the second-generation INSTIs dolutegravir (DTG), bictegravir (BIC), and cabotegravir (CAB) against a panel of IN quadruple mutants. The mutations are centered around G140S/Q148H, including positions L74, E92, and T97 combined with E138A/K/G140S/Q148H. All of the tested INSTIs lose potency against these IN quadruple mutants compared with the wild-type IN. In single-round infection assays, compound 4d retained higher antiviral potencies (EC50 values) than second-generation INSTIs against a subset of quadruple mutants. These findings may advance understanding of mechanisms that contribute to resistance and, in so doing, facilitate development of new INSTIs with improved antiviral profiles.

Performance of an in-house multiplex PCR assay for HIV-1 drug resistance testing - A cheaper alternative

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.

Paediatric antiretroviral therapy challenges with emerging integrase resistance

PURPOSE OF REVIEW

Universal antiretroviral (ART) coverage and virological suppression are fundamental to ending AIDS in children by 2030. Availability of new paediatric dolutegravir (DTG)-based ART formulations is a major breakthrough and will undoubtedly help achieve this goal, but treatment challenges still remain.

RECENT FINDINGS

Paediatric formulations remain limited compared to those for adults, especially for young children, those unable to tolerate DTG or with DTG-based first-line ART failure. Tenofovir alafenamide is virologically superior to standard-of-care backbone drugs in second-line, but paediatric formulations are not widely available. The roles of resistance testing and recycling of backbone drugs following first-line ART failure remain to be determined. Results of trials of novel treatment strategies including dual therapy and long-acting agents are awaited. Although numbers are currently small, safe and effective ART options are urgently required for children developing DTG resistance.

SUMMARY

The antiretroviral treatment gap between adults and children persists. The potential benefits from rollout of new paediatric DTG-based fixed-dose combination ART for first-line treatment are considerable. However, children remain disadvantaged when DTG-based first-line ART fails or cannot be used. Research efforts to address this inequity require prioritisation in order to ensure health outcomes are optimised for all ages in all settings.

Patterns of HIV-1 Drug Resistance Observed Through Geospatial Analysis of Routine Diagnostic Testing in KwaZulu-Natal, South Africa

HIV-1 drug resistance (HIVDR) impedes treatment and control of HIV-1, especially in high-prevalence settings such as KwaZulu-Natal (KZN) province, South Africa. This study merged routine HIV-1 genotypic resistance test (GRT) data with Geographic Information Systems coordinates to assess patterns and geographic distribution of HIVDR in KZN, among ART-experienced adults with virological failure. We curated 3133 GRT records generated between 1 January 2018 and 30 June 2022, which includes the early phase of dolutegravir (DTG) rollout, of which 2735 (87.30%) had HIVDR. Of the 2735, major protease, nucleoside, and non-nucleoside reverse transcriptase inhibitor mutations were detected in 41.24%, 84.97% and 88.08% of GRTs, respectively. Additional genotyping of HIV-1 integrase for 41/3133 (1.31%) GRTs showed that 17/41 (41.46%) had integrase strand transfer inhibitor resistance. Notably, of 26 patients on DTG with integrase genotyping, 9 (34.62%) had DTG-associated resistance mutations. Dual- or triple-class resistance was observed in four of every five GRTs. The odds of HIVDR increased significantly with age, with ≥60 years having 5 times higher odds of HIVDR compared to 18-29 years (p = 0.001). We identified geospatial differences in the burden of HIVDR, providing proof of concept that this could be used for data-driven public health decision making. Ongoing real-time HIVDR surveillance is essential for evaluating the outcomes of the updated South African HIV treatment programme.

Population dynamics of HIV drug resistance during treatment scale-up in Uganda: a population-based longitudinal study

Background

Clinical studies have reported rising pre-treatment HIV drug resistance during antiretroviral treatment (ART) scale-up in Africa, but representative data are limited. We estimated population-level drug resistance trends during ART expansion in Uganda.

Methods

We analyzed data from the population-based open Rakai Community Cohort Study conducted at agrarian, trading, and fishing communities in southern Uganda between 2012 and 2019. Consenting participants aged 15-49 were HIV tested and completed questionnaires. Persons living with HIV (PLHIV) provided samples for viral load quantification and virus deep-sequencing. Sequence data were used to predict resistance. Population prevalence of class-specific resistance and resistance-conferring substitutions were estimated using robust log-Poisson regression.

Findings

Data from 93,622 participant-visits, including 4,702 deep-sequencing measurements, showed that the prevalence of NNRTI resistance among pre-treatment viremic PLHIV doubled between 2012 and 2017 (PR:1.98, 95%CI:1.34-2.91), rising to 9.61% (7.27-12.7%). The overall population prevalence of pre-treatment viremic NNRTI and NRTI resistance among all participants decreased during the same period, reaching 0.25% (0.18% - 0.33%) and 0.05% (0.02% - 0.10%), respectively (p-values for trend = 0.00015, 0.002), coincident with increasing treatment coverage and viral suppression. By the final survey, population prevalence of resistance contributed by treatment-experienced PLHIV exceeded that from pre-treatment PLHIV, with NNRTI resistance at 0.54% (0.44%-0.66%) and NRTI resistance at 0.42% (0.33%-0.53%). Overall, NNRTI and NRTI resistance was predominantly attributable to rtK103N and rtM184V. While 10.52% (7.97%-13.87%) and 9.95% (6.41%-15.43%) of viremic pre-treatment and treatment-experienced PLHIV harbored the inT97A mutation, no major dolutegravir resistance mutations were observed.

Interpretation

Despite rising NNRTI resistance among pre-treatment PLHIV, overall population prevalence of pre-treatment resistance decreased due to treatment uptake. Most NNRTI and NRTI resistance is now contributed by treatment-experienced PLHIV. The high prevalence of mutations conferring resistance to components of current first-line ART regimens among PLHIV with viremia is potentially concerning.

Recent advances in the molecular design and applications of viral RNA-targeting antiviral modalities

Pathogenic viruses are a profound threat to global public health, underscoring the urgent need for the development of efficacious antiviral therapeutics. The advent of RNA-targeting antiviral strategies has marked a significant paradigm shift in the management of viral infections, offering a potent means of control and potential cure. In this review, we delve into the cutting-edge progress in RNA-targeting antiviral agents, encompassing antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), small and bifunctional molecules. We provide an in-depth examination of their strategic molecular design and elucidate the underlying mechanisms of action that confer their antiviral efficacy. By synthesizing recent findings, we shed light on the innovative potential of RNA-targeting approaches and their pivotal role in advancing the frontiers of antiviral drug discovery.

Development and Optimization of Oligonucleotide Ligation Assay (OLA) Probes for Detection of HIV-1 Resistance to Dolutegravir

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_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_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.

GPT-4 performance on querying scientific publications: reproducibility, accuracy, and impact of an instruction sheet

BACKGROUND

Large language models (LLMs) that can efficiently screen and identify studies meeting specific criteria would streamline literature reviews. Additionally, those capable of extracting data from publications would enhance knowledge discovery by reducing the burden on human reviewers.

METHODS

We created an automated pipeline utilizing OpenAI GPT-4 32 K API version "2023-05-15" to evaluate the accuracy of the LLM GPT-4 responses to queries about published papers on HIV drug resistance (HIVDR) with and without an instruction sheet. The instruction sheet contained specialized knowledge designed to assist a person trying to answer questions about an HIVDR paper. We designed 60 questions pertaining to HIVDR and created markdown versions of 60 published HIVDR papers in PubMed. We presented the 60 papers to GPT-4 in four configurations: (1) all 60 questions simultaneously; (2) all 60 questions simultaneously with the instruction sheet; (3) each of the 60 questions individually; and (4) each of the 60 questions individually with the instruction sheet.

RESULTS

GPT-4 achieved a mean accuracy of 86.9% - 24.0% higher than when the answers to papers were permuted. The overall recall and precision were 72.5% and 87.4%, respectively. The standard deviation of three replicates for the 60 questions ranged from 0 to 5.3% with a median of 1.2%. The instruction sheet did not significantly increase GPT-4's accuracy, recall, or precision. GPT-4 was more likely to provide false positive answers when the 60 questions were submitted individually compared to when they were submitted together.

CONCLUSIONS

GPT-4 reproducibly answered 3600 questions about 60 papers on HIVDR with moderately high accuracy, recall, and precision. The instruction sheet's failure to improve these metrics suggests that more sophisticated approaches are necessary. Either enhanced prompt engineering or finetuning an open-source model could further improve an LLM's ability to answer questions about highly specialized HIVDR papers.

Development and emerging trends of drug resistance mutations in HIV: a bibliometric analysis based on CiteSpace

Background

Antiretroviral therapy has led to AIDS being a chronic disease. Nevertheless, the presence of constantly emerging drug resistance mutations poses a challenge to clinical treatment. A systematic analysis to summarize the advancements and uncharted territory of drug resistance mutations is urgently needed and may provide new clues for solving this problem.

Methods

We gathered 3,694 publications on drug resistance mutations from the Web of Science Core Collection with CiteSpace software and performed an analysis to visualize the results and predict future new directions and emerging trends. Betweenness centrality, count, and burst value were taken as standards.

Results

The number of papers on HIV medication resistance mutations during the last 10 years shows a wave-like trend. In terms of nation, organization, and author, the United States (1449), University of London (193), and Mark A. Wainberg (66) are the most significant contributors. The most frequently cited article is "Drug resistance mutations for surveillance of transmitted HIV-1 drug-resistance: 2009 update." Hot topics in this field include "next-generation sequencing," "tenofovir alafenamide," "children," "regimens," "accumulation," "dolutegravir," "rilpivirine," "sex," "pretreatment drug resistance," and "open label." Research on drug resistance in teenagers, novel mutation detection techniques, and drug development is ongoing, and numerous publications have indicated the presence of mutations related to current medications. Therefore, testing must be performed regularly for patients who have used medications for a long period. Additionally, by choosing medications with a longer half-life, patients can take fewer doses of their prescription, increasing patient compliance.

Conclusion

This study involved a bibliometric visualization analysis of the literature on drug resistance mutations, providing insight into the field's evolution and emerging patterns and offering academics a resource to better understand HIV drug resistance mutations and contribute to the field's advancement.

HIV transmission dynamics and population-wide drug resistance in rural South Africa

Despite expanded antiretroviral therapy (ART) in South Africa, HIV-1 transmission persists. Integrase strand transfer inhibitors (INSTI) and long-acting injectables offer potential for superior viral suppression, but pre-existing drug resistance could threaten their effectiveness. In a community-based study in rural KwaZulu-Natal, prior to widespread INSTI usage, we enroled 18,025 individuals to characterise HIV-1 drug resistance and transmission networks to inform public health strategies. HIV testing and reflex viral load quantification were performed, with deep sequencing (20% variant threshold) used to detect resistance mutations. Phylogenetic and geospatial analyses characterised transmission clusters. One-third of participants were HIV-positive, with 21.7% having detectable viral loads; 62.1% of those with detectable viral loads were ART-naïve. Resistance to older reverse transcriptase (RT)-targeting drugs was found, but INSTI resistance remained low (<1%). Non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance, particularly to rilpivirine (RPV) even in ART-naïve individuals, was concerning. Twenty percent of sequenced individuals belonged to transmission clusters, with geographic analysis highlighting higher clustering in peripheral and rural areas. Our findings suggest promise for INSTI-based strategies in this setting but underscore the need for RPV resistance screening before implementing long-acting cabotegravir (CAB) + RPV. The significant clustering emphasises the importance of geographically targeted interventions to effectively curb HIV-1 transmission.

Prevalence of Emergent Dolutegravir Resistance Mutations in People Living with HIV: A Rapid Scoping Review

BACKGROUND

Dolutegravir (DTG) is a cornerstone of global antiretroviral (ARV) therapy (ART) due to its high efficacy and favorable tolerability. However, limited data exist regarding the risk of emergent integrase strand transfer inhibitor (INSTI) drug-resistance mutations (DRMs) in individuals receiving DTG-containing ART.

METHODS

We performed a PubMed search using the term "Dolutegravir", last updated 18 December 2023, to estimate the prevalence of VF with emergent INSTI DRMs in people living with HIV (PLWH) without previous VF on an INSTI who received DTG-containing ART.

RESULTS

Of 2131 retrieved records, 43 clinical trials, 39 cohorts, and 6 cross-sectional studies provided data across 6 clinical scenarios based on ART history, virological status, and co-administered ARVs: (1) ART-naïve PLWH receiving DTG plus two NRTIs; (2) ART-naïve PLWH receiving DTG plus lamivudine; (3) ART-experienced PLWH with VF on a previous regimen receiving DTG plus two NRTIs; (4) ART-experienced PLWH with virological suppression receiving DTG plus two NRTIs; (5) ART-experienced PLWH with virological suppression receiving DTG and a second ARV; and (6) ART-experienced PLWH with virological suppression receiving DTG monotherapy. The median proportion of PLWH in clinical trials with emergent INSTI DRMs was 1.5% for scenario 3 and 3.4% for scenario 6. In the remaining four trial scenarios, VF prevalence with emergent INSTI DRMs was ≤0.1%. Data from cohort studies minimally influenced prevalence estimates from clinical trials, whereas cross-sectional studies yielded prevalence data lacking denominator details.

CONCLUSIONS

In clinical trials, the prevalence of VF with emergent INSTI DRMs in PLWH receiving DTG-containing regimens has been low. Novel approaches are required to assess VF prevalence with emergent INSTI DRMs in PLWH receiving DTG in real-world settings.

Virological Findings and Treatment Outcomes of Cases That Developed Dolutegravir Resistance in Malawi's National HIV Treatment Program

Millions of Africans are on dolutegravir-based antiretroviral therapy (ART), but few detailed descriptions of dolutegravir resistance and its clinical management exist. We reviewed HIV drug resistance (HIVDR) testing application forms submitted between June 2019 and October 2022, data from the national HIVDR database, and genotypic test results. We obtained standardized ART outcomes and virological results of cases with dolutegravir resistance, and explored associations with dolutegravir resistance among individuals with successful integrase sequencing. All cases were on two nucleoside reverse transcriptase inhibitors (NRTIs)/dolutegravir, and had confirmed virological failure, generally with prolonged viremia. Among 89 samples with successful integrase sequencing, 24 showed dolutegravir resistance. Dolutegravir resistance-associated mutations included R263K (16/24), E138K (7/24), and G118R (6/24). In multivariable logistic regression analysis, older age and the presence of high-level NRTI resistance were significantly associated with dolutegravir resistance. After treatment modification recommendations, four individuals (17%) with dolutegravir resistance died, one self-discontinued ART, one defaulted, and one transferred out. Of the 17 remaining individuals, 12 had follow-up VL results, and 11 (92%) were <1000 copies/mL. Twenty-four cases with dolutegravir resistance among 89 individuals with confirmed virological failure suggests a considerable prevalence in the Malawi HIV program. Successful management of dolutegravir resistance was possible, but early mortality was high. More research on the management of treatment-experienced individuals with dolutegravir resistance is needed.

The Discovery of Indole-2-carboxylic Acid Derivatives as Novel HIV-1 Integrase Strand Transfer Inhibitors

As an important antiviral target, HIV-1 integrase plays a key role in the viral life cycle, and five integrase strand transfer inhibitors (INSTIs) have been approved for the treatment of HIV-1 infections so far. However, similar to other clinically used antiviral drugs, resistance-causing mutations have appeared, which have impaired the efficacy of INSTIs. In the current study, to identify novel integrase inhibitors, a set of molecular docking-based virtual screenings were performed, and indole-2-carboxylic acid was developed as a potent INSTI scaffold. Indole-2-carboxylic acid derivative 3 was proved to effectively inhibit the strand transfer of HIV-1 integrase, and binding conformation analysis showed that the indole core and C2 carboxyl group obviously chelated the two Mg2+ ions within the active site of integrase. Further structural optimizations on compound 3 provided the derivative 20a, which markedly increased the integrase inhibitory effect, with an IC50 value of 0.13 μM. Binding mode analysis revealed that the introduction of a long branch on C3 of the indole core improved the interaction with the hydrophobic cavity near the active site of integrase, indicating that indole-2-carboxylic acid is a promising scaffold for the development of integrase inhibitors.

HIV transmission dynamics and population-wide drug resistance in rural South Africa

Despite the scale-up of antiretroviral therapy (ART) in South Africa, HIV-1 incidence remains high. The anticipated use of potent integrase strand transfer inhibitors and long-acting injectables aims to enhance viral suppression at the population level and diminish transmission. Nevertheless, pre-existing drug resistance could impede the efficacy of long-acting injectable ART combinations, such as rilpivirine (an NNRTI) and cabotegravir (an INSTI). Consequently, a thorough understanding of transmission networks and geospatial distributions is vital for tailored interventions, including pre-exposure prophylaxis with long-acting injectables. However, empirical data on background resistance and transmission networks remain limited. In a community-based study in rural KwaZulu-Natal (2018-2019), prior to the widespread use of integrase inhibitor-based first-line ART, we performed HIV testing with reflex HIV-1 RNA viral load quantification on 18,025 participants. From this cohort, 6,096 (33.9%) tested positive for HIV via ELISA, with 1,323 (21.7%) exhibiting detectable viral loads (> 40 copies/mL). Of those with detectable viral loads, 62.1% were ART-naïve, and the majority of the treated were on an efavirenz + cytosine analogue + tenofovir regimen. Deep sequencing analysis, with a variant abundance threshold of 20%, revealed NRTI resistance mutations such as M184V in 2% of ART-naïve and 32% of treated individuals. Tenofovir resistance mutations K65R and K70E were found in 12% and 5% of ART-experienced individuals, respectively, and in less than 1% of ART-naïve individuals. Integrase inhibitor resistance mutations were notably infrequent (< 1%). Prevalence of pre-treatment drug resistance to NNRTIs was 10%, predominantly consisting of the K103N mutation. Among those with viraemic ART, NNRTI resistance was 50%, with rilpivirine-associated mutations observed in 9% of treated and 6% of untreated individuals. Cluster analysis revealed that 20% (205/1,050) of those sequenced were part of a cluster. We identified 171 groups with at least two linked participants; three quarters of clusters had only two individuals, and a quarter had 3-6 individuals. Integrating phylogenetic with geospatial analyses, we revealed a complex transmission network with significant clustering in specific regions, notably peripheral and rural areas. These findings derived from population scale genomic analyses are encouraging in terms of the limited resistance to DTG, but indicate that transitioning to long-acting cabotegravir + rilpivirine for transmission reduction should be accompanied by prior screening for rilpivirine resistance. Whole HIV-1 genome sequencing allowed identification of significant proportions of clusters with multiple individuals, and geospatial analyses suggesting decentralised networks can inform targeting public health interventions to effectively curb HIV-1 transmission.