Integrase Strand Transfer Inhibitors Resistance Mutations Research Articles

HIV-1 subtype-specific drug resistance on dolutegravir-based antiretroviral therapy: protocol for a multicentre longitudinal study (DTG RESIST).

HIV drug resistance poses a challenge to the United Nation's goal of ending the HIV/AIDS epidemic. The integrase strand transfer inhibitor (InSTI) dolutegravir, which has a higher resistance barrier, was endorsed by the World Health Organization in 2019 for first-, second-, and third-line antiretroviral therapy (ART). This multiplicity of roles of dolutegravir in ART may facilitate the emergence of dolutegravir resistance. DTG RESIST is a multicentre longitudinal study of adults and adolescents living with HIV in sub-Saharan Africa, Asia, and South and Central America who experienced virologic failure on dolutegravir-based ART. At the time of virologic failure whole blood will be collected and processed to prepare plasma or dried blood spots. Laboratories in Durban, Mexico City and Bangkok will perform genotyping. Analyses will focus on (i) individuals who experienced virologic failure on dolutegravir, and (ii) on those who started or switched to such a regimen and were at risk of virologic failure. For population (i), the outcome will be any InSTI drug resistance mutations, and for population (ii) virologic failure defined as a viral load >1000 copies/mL. Phenotypic testing will focus on non-B subtype viruses with major InSTI resistance mutations. Bayesian evolutionary models will explore and predict treatment failure genotypes. The study will have intermediate statistical power to detect differences in resistance mutation prevalence between major HIV-1 subtypes; ample power to identify risk factors for virologic failure and limited power for analysing factors associated with individual InSTI drug resistance mutations. The research protocol was approved by the Biomedical Research Ethics Committee at the University of KwaZulu-Natal, South Africa, and the Ethics Committee of the Canton of Bern, Switzerland. All sites participate in IeDEA and have obtained ethics approval from their local ethics committee to conduct the additional data collection. NCT06285110. - DTG RESIST is a large international study to prospectively examine emergent dolutegravir resistance in diverse settings characterised by different HIV-1 subtypes, provision of ART, and guidelines on resistance testing. - Embedded within the International epidemiology Databases to Evaluate AIDS (IeDEA), DTG RESIST will benefit from harmonized clinical data across participating sites and expertise in clinical, epidemiological, biological, and computational fields. - Procedures for sequencing and assembling genomes from different HIV-1 strains will be developed at the heart of the HIV epidemic, by the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), in Durban, South Africa. Phenotypic testing, Genome Wide Association Study (GWAS) methods and Bayesian evolutionary models will explore and predict treatment failure genotypes. - A significant limitation is the absence of genotypic resistance data from participants before they started dolutegravir treatment, as collecting and bio-banking pre-treatment samples was not feasible at most IeDEA sites. Consistent and harmonized data on adherence to treatment are also lacking. - The distribution of HIV-1 subtypes across different sites is uncertain, which may limit the statistical power of the study in analysing patterns and risk factors for dolutegravir resistance. The results from GWAS and Bayesian modelling analyses will be preliminary and hypothesis-generating.

Portable Nanopore sequencing solution for next-generation HIV drug resistance testing

BackgroundTackling 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. MethodsWe 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). ResultsA 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. ConclusionsOur accurate and affordable HIV drug resistance testing solution is adaptable for both individual patient care and large-scale surveillance initiatives.

High viral suppression and detection of dolutegravir-resistance associated mutations in treatment-experienced Tanzanian adults living with HIV-1 in Dar es Salaam

To curb HIV infection rate in Tanzania, antiretroviral therapy (ART) has been scaled up since 2006, and in 2019, the country shifted to regimen including dolutegravir as a default first line. We assessed the success of ART and the contribution of HIV drug resistance (HIVDR) to unsuppressed viral loads. Between February and May 2023 a cross-sectional survey with random sampling was conducted in the six clinics in an urban cohort in Dar es Salaam. Patients with unsuppresed viral loads (local criteria viral load (VL) ≥ 1000 copies/mL) were tested for HIVDR mutations using the WHO adapted protocol for plasma samples. Mutations were interpreted using the Stanford HIVDR database. In total 600 individuals participated in this survey, the majority were female (76.83%), mean age (pm standard deviation) was 44.0 (pm 11.6) years. The median duration on ART (interquartile range) was 6.5 (3.9–10.2) years. Approximately 99% were receiving tenofovir + lamivudine + dolutegravir as a fixed dose combination. VL testing was successful in 99.67% (598/600) of survey patients and only 33 had VL ≥ 1000 copies/mL, resulting in a viral suppression level of 94.48% (565/598, 95% CI 92.34–96.17%). For 23 samples, protease and reverse transcriptase (RT) genotyping were successful, with 13 sequences containing RT inhibitor surveillance drug resistance mutations (SDRMs) (56.5%). No SDRM against protease inhibitors were detected. Thirty samples were successfully genotyped for integrase with 3 sequences (10.08%) containing integrase strand transfer inhibitor (INSTI) SDRMs. In samples successfully genotyped in the three genetic regions, 68.18% (16/22) had a genotypic susceptibility score (GSS) ≥ 2.5 for the concurrent regimen, implying factors beyond drug resistance caused the unsuppressed viral load. For five patients, GSS indicated that HIVDR may have caused the unsuppressed viral load. All three patients with INSTI resistance mutations were highly resistant to dolutegravir and accumulated nucleoside and non-nucleoside RT inhibitor HIVDR mutations. Although in this cohort the last 95 UNAIDS target was almost achieved, HIVDR mutations, including INSTIs resistance mutations were detected in HIV-positive individuals taking ART for at least one year. We recommend the design and implementation of high-impact interventions to prevent the increase of HIVDR, failure of dolutegravir and address the non-resistance factors in the study area.

Increasing trend of transmitted integrase inhibitor resistance in a cohort of antiretroviral therapy-naive people living with HIV.

Drug regimens containing integrase strand transfer inhibitors (INSTIs) are widely recommended by international guidelines for ART-naive people living with HIV (PLWH).1,2 However, INSTI resistance mutations are uncommon and therefore their surveillance is not suggested before starting ART. The aim of the study was to evaluate the prevalence trend of transmitted INSTI drug resistance (DR) and to assess factors associated with transmitted INSTI resistance among ART-naive PLWH over the past decade. We conducted a time-trend, single-centre study over the period 2009–19 on adult naive PLWH with a genotypic resistance test (GRT) performed before the ART initiation. GRT was determined by Sanger sequencing using an ABI PRISM 3130xl Genetic Analyzer (Applied Biosystems, Foster City, CA, USA); we included in the analysis the immediate pre-ART GRT available in people newly diagnosed with HIV infection. The degree of resistance to each INSTI drug was calculated using the Genotypic Resistance Interpretation Algorithm of the Stanford HIV Drug Resistance Database Program (version 9.1.1) (https://hivdb.stanford.edu/hivdb/by-patterns/). The obtained scores were used to classify the presence of low-level, intermediate or high-level resistance to each INSTI drug and to the INSTI drug class. DR within the INSTI class was defined by the presence of at least low-level resistance to ≥1 drug of the INSTI class.

Prevalence of resistance mutations associated with integrase inhibitors in therapy-naive HIV-positive patients in Baoding, Hebei province, China.

Antiretroviral therapy (ART) regimens containing integrase strand transfer inhibitors (INSTIs) are the recommended treatment for human immunodeficiency virus type 1 (HIV-1)-infected patients in the most recent guidelines in China. In this study, we investigated INSTI resistance mutations in newly diagnosed therapy-naive HIV-positive patients in Baoding City, Hebei Province (China) to provide guidance for implementing routine INSTI-associated HIV-1 genotypic resistance testing. Plasma samples were collected from HIV-1-infected patients without treatment at Baoding People’s Hospital from January 2020 to December 2021. The part of HIV-1 pol gene encoding integrase was amplified, sequenced, and analyzed for INSTI resistance. Clinical data including demographic data, CD4+ T cell counts, HIV-RNA loads, and resistance mutations were collected. Treatment-naïve HIV-1 patients (n = 131) were enrolled. We identified ten genotypes, and the predominant genotype was CRF01_AE in 67 patients (51.15%), CRF07_ BC in 39 patients (29.77%), subtype B in 11 patients (8.40%), and other subtypes (CRF68_01B, 3.82%; CRF55_01B, 1.53%, CRF80_0107, 1.53%; URFs 1.53%; and CRF103_01B, CRF59_01B, and CRF65_cpx, 1.4% each). Four major (E138A, R263k, G140S, and S147G) and three accessory (H51Y, Q146QL, and S153F) INSTI-resistance mutations were observed (genotype CRF01_AE, three patients; genotype B, one patient; and genotype CRF07_BC, one patient), resulting in different degrees of resistance to the following five INSTIs: raltegravir, elvitegravir, dolutegravir, bictegravir, and cabotegravir. The overall resistance rate was 3.82% (5/131). All INSTI-resistant strains were cross-resistant. The primary INSTI drug resistance rate among newly diagnosed HIV-infected patients in Baoding was low, but monitoring and research on HIV INSTI resistance should be strengthened in Baoding because INSTI-based regimen prescriptions are anticipated to increase in the near future.

High-level dolutegravir resistance can emerge rapidly from few variants and spread by recombination: implications for integrase strand transfer inhibitor salvage therapy.

The integrase strand transfer inhibitor (INSTI) dolutegravir is commonly used in combination antiretroviral therapy regimens and retains strong potency even with primary resistance mutations to some other INSTIs. Acquisition of accessory mutations to primary mutations results in significant increases in dolutegravir resistance. Previously, we reported that addition of the secondary mutation T97A can result in rapid treatment failure in individuals with INSTI mutations at positions 140 and 148. Here, we conducted a detailed case study of one of these individuals and find that T97A-containing HIV emerged from a large replicating population from only a few (≤4) viral lineages. When combined with primary INSTI resistance mutations, T97A provides a strong selective advantage; the finding that T97A-containing variants spread by replication and recombination, and persisted for months after discontinuing dolutegravir, has important implications as dolutegravir is rolled out worldwide.

Integrase Strand Transfer Inhibitor (INSTI) Genotypic Resistance Analysis in Treatment-Naive, INSTI Free Antiretroviral-Experienced and INSTI-Experienced Turkish Patients Infected with HIV-1.

Integrase strand transfer inhibitors (INSTIs) are currently the standard of practice for first-line HIV therapy for most patients. We evaluated the mutations associated with INSTI resistance in naive HIV-1 infected patients and treated them with antiretrovirals (ART). The study, conducted in the 2018 - 2020 period, included 50 ART-naïve patients, 69 INSTI free ART-experienced patients, and 82 INSTI-experienced patients. INSTI resistance mutations were interpreted using the Stanford University HIVdb Program algorithm. INSTI resistance was not detected in ART naïve patients. At least one INSTI resistance mutation was detected in 10% of the INSTI-free patients and 29% of the INSTI-treated patients. Major INSTI-mutations E138K, Y143R, S147G, Q148R, N155H, and E157Q were found in raltegravir. Additional mutations, E92Q, E138K, G140A, S147G, and Q148R were found in elvitegravir; E192Q, E138K/T, G140A/S, S147G, Q148H/R, N155H, E157Q were found in dolutegravir (DTG) experienced patients. According to all drug classes, drug resistance mutation prevalences were determined at the rate of 60%, 46%, and 46% in the RAL, EVG, and DTG groups, respectively. Our findings provide data for treatment and resistance management of INSTIs and may provide feedback for INSTIs resistance surveillance consensus-building efforts. In viral rebound under INSTI treatment, INSTI-resistant mutations follow typical INSTI resistance pathways and high resistance rates. INSTI resistance genotypic analysis should be considered before any DTG-based regimes can be initiated in the future, and reduced DTG susceptibility should be carefully monitored and investigated.

HIV-1 Genetic Diversity and Natural Polymorphisms of the Integrase Gene in Integrase Inhibitor-Naive Patients in Harare, Zimbabwe.

Previously used as part of salvage therapy, integrase strand transfer inhibitors (INSTIs) have become part of the preferred antiretroviral therapy (ART) first-line regimen in most low- to middle-income countries. With the extensive use of dolutegravir in first-line ART, drug resistance mutations to INSTIs are inevitable. Therefore, active monitoring and surveillance of INSTI drug resistance is required. The aim of this study was to evaluate the genetic diversity of the integrase gene and determine pretreatment INSTI resistance in Harare, Zimbabwe. Forty-four HIV-1 Integrase sequences from 65 were obtained from treatment-naive individuals using a custom genotyping method. Drug resistance mutations were determined using the Stanford HIV Drug Resistance Interpretation program. Viral subtyping was done by phylogenetic analysis and the REGA HIV subtyping tool determined recombinants. Natural polymorphisms were evaluated relative to the global subtype B and C consensus sequences. One hundred ninety-two sequences from the region were accessed from GenBank to assess differences between the Zimbabwean sequences and those from neighboring countries. No major INSTI resistance mutations were detected; however, the L74I polymorphism was detected in three sequences of the 44 (6.8%). There was little genetic variability in the Integrase gene, with a mean genetic distance range of 0.053015. The subtype C consensus was identical to the global subtype C consensus and varied from the global subtype B consensus at five major positions: T124A, V201I, T218I, D278A, and S283G. This study has provided baseline sequence data on the presence of HIV-1 subtype C Integrase gene drug resistance mutations from Harare, Zimbabwe.

633. Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) Efficacy in Participants with Pre-Existing Primary Integrase Inhibitor Resistance Through 48 Weeks of Phase 3 Clinical Trials

BackgroundPre-existing drug resistance can affect the efficacy of antiretroviral therapy. Studies in treatment-naïve and virologically suppressed participants have demonstrated safety and efficacy of B/F/TAF, including in patients with M184V/I mutations. In this pooled analysis, we investigated virologic outcomes after 48 weeks of B/F/TAF treatment in individuals with pre-existing integrase strand transfer inhibitor resistance (INSTI-R).MethodsAlthough INSTI-R was prohibited per study entry criteria, pre-existing INSTI-R (T66A/I/K, E92G/Q, F121Y, Y143C/H/R, S147G, Q148H/K/R, N155H/S, R263K) was evaluated in participants from studies 1489, 1490, 1844, 1878, 4030. INSTI-R was assessed by historical genotypes and/or retrospective deepType HIV assay (Seq-IT, Germany), GenoSure IN, GenoSure Archive (Monogram Biosciences). Virologic outcomes were defined by last on-treatment observation carried forward (LOCF) method.ResultsPre-existing primary INSTI-R substitutions were detected in 20/1907 participants (1.0%) after enrolment. Of the 20, 75% were male, 30% white, and 85% had HIV-1 subtype B, baseline median CD4 counts of 594 (IQR 517, 700), and median age of 52 (43, 59) years. One participant was treatment-naïve with a baseline viral load of 30,000 copies/ml and had Q148H (+ G140S on plasma RNA genotype) and was sensitive to bictegravir (< 2.5-fold change). The other 19 participants were virologically suppressed and had E92G (n=3), Y143C (n=2), Y143H (n=4), S147G (n=2), N155S (n=1), Q148H (n=3), Q148K (n=1), Q148R (n=1), or R263K (n=2) INSTI-R mutations by DNA genotype. The treatment-naïve individual was suppressed by Week 4 and maintained viral loads of < 50 copies/mL through Week 48. All suppressed participants had HIV RNA < 50 copies/mL throughout Week 48. All study participants had virologic success by LOCF (< 50 copies/mL) at Week 48.ConclusionParticipants with primary INSTI-R substitutions had or maintained virologic suppression through 48 weeks of B/F/TAF treatment. Consistent with the potent in vitro activity of bictegravir against many INSTI-R mutations, these virologic outcomes suggest that B/F/TAF may have potential as a treatment option for some patients with pre-existing INSTI-R, if confirmed by further studies.DisclosuresMichelle L. D’Antoni, PhD, Gilead Sciences (Employee, Shareholder) Kristen Andreatta, MSc, Gilead Sciences (Employee, Shareholder) Rima K. Acosta, BS, Gilead Sciences, Inc. (Employee, Shareholder) Silvia Chang, Masters, Gilead Sciences (Employee, Shareholder) Ross Martin, PhD, Gilead Sciences (Employee, Shareholder) Kirsten L. White, PhD, Gilead Sciences, Inc. (Employee, Shareholder)

Comparable In Vitro Activities of Second-Generation HIV-1 Integrase Strand Transfer Inhibitors (INSTIs) on HIV-1 Clinical Isolates with INSTI Resistance Mutations.

Second-generation HIV-1 integrase strand transfer inhibitors (INSTIs) dolutegravir (DTG), bictegravir (BIC), and cabotegravir (CAB) showed a high genetic barrier to resistance and limited cross-resistance with first-generation INSTIs raltegravir (RAL) and elvitegravir (EVG). In this study, DTG, BIC, and CAB demonstrated a comparable activity on a panel of INSTI-resistant strains isolated from patients exposed to RAL, EVG, and/or DTG, with a significantly reduced susceptibility only with the pathway Q148H/K/R plus one to two additional INSTI mutations.

A systematic review of the genetic mechanisms of dolutegravir resistance.

BackgroundCharacterizing the mutations selected by the integrase strand transfer inhibitor (INSTI) dolutegravir and their effects on susceptibility is essential for identifying viruses less likely to respond to dolutegravir therapy and for monitoring persons with virological failure (VF) on dolutegravir therapy.MethodsWe systematically reviewed dolutegravir resistance studies to identify mutations emerging under dolutegravir selection pressure, the effect of INSTI resistance mutations on in vitro dolutegravir susceptibility, and the virological efficacy of dolutegravir in antiretroviral-experienced persons.Results and conclusionsWe analysed 14 studies describing 84 in vitro passage experiments, 26 studies describing 63 persons developing VF plus INSTI resistance mutations on a dolutegravir-containing regimen, 41 studies describing dolutegravir susceptibility results, and 22 clinical trials and 16 cohort studies of dolutegravir-containing regimens. The most common INSTI resistance mutations in persons with VF on a dolutegravir-containing regimen were R263K, G118R, N155H and Q148H/R, with R263K and G118R predominating in previously INSTI-naive persons. R263K reduced dolutegravir susceptibility ∼2-fold. G118R generally reduced dolutegravir susceptibility >5-fold. The highest levels of reduced susceptibility occurred in viruses containing Q148 mutations in combination with G140 and/or E138 mutations. Dolutegravir two-drug regimens were highly effective for first-line therapy and for virologically suppressed persons provided dolutegravir’s companion drug was fully active. Dolutegravir three-drug regimens were highly effective for salvage therapy in INSTI-naive persons provided one or more of dolutegravir’s companion drugs was fully active. However, dolutegravir monotherapy in virologically suppressed persons and functional dolutegravir monotherapy in persons with active viral replication were associated with a non-trivial risk of VF plus INSTI resistance mutations.

Resistance of human immunodeficiency virus type 1 to integrase strand transfer inhibitors in Croatia

Integrase strand transfer inhibitors (INSTIs) are the latest class of antiretroviral drugs that prevent the integration of proviral DNA into the host genome. The aim of this study was to describe, for the first time, INSTI resistance mutations observed in Croatian HIV-infected patients. Methods: The study was conducted between March 2016 and September 2018 and included 4 previously untreated patients (antiretroviral, ARV-naive) as well as 18 unsuccessfully treated HIV-infected patients (ARV-experienced) that have been tested for INSTI resistance. The genetic data on INSTI resistance was obtained by population-based sequencing of the integrase gene. Resistance analysis to other classes of antiretroviral drugs has been performed in some patients by sequencing the protease gene and a part of the reverse transcriptase HIV-1 gene. Results: INSTI resistance mutations were not found in ARV-naive patients. Mutations associated with resistance to INSTIs have been observed in 5 of 18 (27.8%) patients failing INSTI-based ARV regiment. Resistance to INSTIs in ARV-experienced patients was attributed to major resistance mutations Q148R, N155H and E92Q that confer resistance to two INSTIs (raltegravir and elvitegravir). Conclusions: The results of this study describe the first 5 cases of ARV-experienced HIV-1 infected patients with clinically significant resistance to INSTIs, and emphasize the need for continuous surveillance of INSTI resistance in patients experiencing virological failure to antiretroviral treatment in Croatia.

HIV-1 Integrase Resistance among Highly Antiretroviral Experienced Patients from Morocco

Background: We aimed to analyze for the first time in Morocco the integrase (IN) sequence variability among highly experienced HIV-1-infected patients with no prior IN strand transfer inhibitor (INSTI) exposure who failed on reverse transcriptase inhibitors and protease inhibitors. Methods: The HIV-1 IN region was sequenced from plasma samples of all 78 recruited patients. The amino acid IN sequences were HIV-1 subtyped and screened for the presence of polymorphisms against the HxB2 clade B consensus sequence by the geno2pheno subtyping tool and interpreted for drug resistance according to the Stanford algorithm. Results: The viral subtypes were subtype B (88.4%), CRF02_AG (8.9%), CRF01_AE (1.28%), and subtype C (1.28%). The major INSTI resistance mutations at positions 66, 92, 118, 138, 140, 143, 147, 148, 155, and 263 were absent, while two accessory mutations, L74M/I, known to have no clinical impact to INSTIs in the absence of the major resistance mutations, were detected in three samples (3.84%; two CRF02_AG and one CRF01_AE). Others specific substitutions with an uncertain role on the HIV-1 susceptibility to INSTIs at positions 72, 101, 119, 124, 156, 165, 193, 201, 203, 206, 230, 232, and 249 were found to be relatively common. Conclusion: This study demonstrated that INSTIs should be an excellent alternative for salvage therapy in highly experienced patients with multidrug resistant viruses in Morocco.

Prevalence and clinical impact of minority resistant variants in patients failing an integrase inhibitor-based regimen by ultra-deep sequencing.

Integrase strand transfer inhibitors (INSTIs) are recommended by international guidelines as first-line therapy in antiretroviral-naive and -experienced HIV-1-infected patients. This study aimed at evaluating the prevalence at failure of INSTI-resistant variants and the impact of baseline minority resistant variants (MiRVs) on the virological response to an INSTI-based regimen. Samples at failure of 134 patients failing a raltegravir-containing (n = 65), an elvitegravir-containing (n = 20) or a dolutegravir-containing (n = 49) regimen were sequenced by Sanger sequencing and ultra-deep sequencing (UDS). Baseline samples of patients with virological failure (VF) (n = 34) and of those with virological success (VS) (n = 31) under INSTI treatment were sequenced by UDS. Data were analysed using the SmartGene platform, and resistance was interpreted according to the ANRS algorithm version 27. At failure, the prevalence of at least one INSTI-resistant variant was 39.6% by Sanger sequencing and 57.5% by UDS, changing the interpretation of resistance in 17/134 (13%) patients. Among 53 patients harbouring at least one resistance mutation detected by both techniques, the most dominant INSTI resistance mutations were N155H (45%), Q148H/K/R (23%), T97A (19%) and Y143C (11%). There was no difference in prevalence of baseline MiRVs between patients with VF and those with VS. MiRVs found at baseline in patients with VF were not detected at failure either in majority or minority mutations. UDS is more sensitive than Sanger sequencing at detecting INSTI MiRVs at treatment failure. The presence of MiRVs at failure could be important to the decision to switch to other INSTIs. However, there was no association between the presence of baseline MiRVs and the response to INSTI-based therapies in our study.

Primary resistance to integrase strand transfer inhibitors in patients infected with diverse HIV-1 subtypes in sub-Saharan Africa

To investigate the prevalence and patterns of major and accessory resistance mutations associated with integrase strand transfer inhibitors (INSTIs), across diverse HIV-1 subtypes in sub-Saharan Africa. pol gene sequences were obtained using Illumina next-generation sequencing from 425 INSTI-naive HIV-infected adults from Kenya (21.2%), Nigeria (7.3%), South Africa (22.8%), Uganda (25.2%) and Zambia (23.5%). Drug resistance interpretation was based on the IAS 2017 mutation list and accessory mutations from Stanford HIVdb with resistance penalty scores of ≥10 to at least 1 INSTI. Resistance was further classified based on sensitivity thresholds of ≥20% (Sanger sequencing) and 1%-20% for low-frequency variants (next-generation sequencing). Of 425 genotypes, 48.7% were subtype C, 28.5% A, 10.1% D, 2.8% G and 9.9% were recombinants. Major INSTI resistance mutations were detected only at <20% threshold, at a prevalence of 2.4% (2.5% in subtype A, 2.4% C, 0% D, 8.3% G and 2.4% in recombinants) and included T66A/I (0.7%), E92G (0.5%), Y143C/S (0.7%), S147G (0.2%) and Q148R (0.5%). Accessory mutations occurred at a prevalence of 15.1% at the ≥20% threshold (23.1% in subtype A, 8.7% C, 11.6% D, 25% G and 23.8% in recombinants), and included L74I/M (10.4%), Q95K (0.5%), T97A (4%), E157Q (0.7%) and G163R/K (0.7%). Major INSTI resistance mutations were rare and only occurred at low-level resistance detection thresholds. INSTI-based regimens are expected to be effective across the different major HIV-1 subtypes in the region.

Integrase Strand Transfer Inhibitor Resistance Mutations in Antiretroviral Treatment-naïve Patients in Korea: a Prospective, Observational Study.

The present study investigated prevalence of integrase strand transfer inhibitors (INSTI) resistance mutations in HIV-1-infected antiretroviral therapy (ART)-naïve patients in Korea. From 106 plasma samples, amplification and sequencing of integrase genes was performed, and major or minor mutations were calculated by the Stanford HIV drug resistance mutation interpretation algorithm. No major INSTI resistance mutations were found, and 14 minor mutations were detected in 13 (12.3%) patients. The present data support the recommendation that routine testing for INSTI resistance mutations before starting ART is not necessary.

Pretreatment integrase strand transfer inhibitor resistance in North Carolina from 2010-2016.

We sought to define the prevalence of pretreatment integrase strand transfer inhibitor (INSTI) resistance and assess the transmission networks of those with pretreatment INSTI resistance. A retrospective cohort study of HIV-positive patients with genotypic resistance testing sent to a single referral laboratory in North Carolina between 2010 and 2016. We linked genotype and public health data for in-care HIV-positive individuals to determine the prevalence of INSTI resistance among treatment-naive (defined as those with a first genotype ≤3 months after diagnosis) and treatment-experienced (defined as those with a first genotype >3 months after diagnosis) patients. We performed molecular and phylogenetic analyses to assess whether pretreatment INSTI resistance mutations represented clustered HIV transmission. Of 8825 individuals who contributed sequences for protease, reverse transcriptase, or INSTI genotypic resistance testing during the study period, 2784 (31%) contributed at least one sequence for INSTI resistance testing. Of these, 840 were treatment-naive individuals and 20 [2.4%, 95% confidence interval (CI): 1.5, 3.6%] had INSTI mutations; only two (0.2%, 95% CI: 0.02, 0.9%) had major mutations. Of 1944 treatment-experienced individuals, 9.6% (95% CI: 8.3, 11.0%) had any INSTI mutation and 7.0% (95% CI: 5.9, 8.3%) had major mutations; the prevalence of INSTI mutations among treatment-experienced patients decreased overtime (P < 0.001). In total 12 of 20 individuals with pretreatment INSTI mutations were part of 10 molecular transmission clusters; only one cluster shared identical minor mutations. The prevalence of major pretreatment INSTI resistance is very low. Pretreatment INSTI mutations do not appear to represent clustered HIV transmission.

Analysis of HIV Integrase Resistance in Black Men Who Have Sex with Men in the United States.

Resistance to reverse transcriptase and protease inhibitors was frequently detected in HIV from black men who have sex with men (MSM) enrolled in the HIV prevention trials network (HPTN) 061 study. In this study, integrase strand transfer inhibitor (INSTI) resistance was analyzed in black MSM enrolled in HPTN 061 (134 infected at enrollment and 23 seroconverters) and a follow-up study, HPTN 073 (eight seroconverters). The ViroSeq HIV-1 Integrase Genotyping Kit (Abbott Molecular) was used for analysis. Major INSTI resistance mutations were not detected in any of the samples. HIV from 14 (8.4%) of the 165 men, including 4 (12.9%) of 31 seroconverters, had accessory or polymorphic INSTI-associated mutations. The most frequently detected mutation was E157Q. These findings are promising because INSTI-based regimens are now recommended for first-line antiretroviral treatment and because long-acting cabotegravir is being evaluated for pre-exposure prophylaxis.

Quantitative evaluation of the antiretroviral efficacy of dolutegravir

The second-generation HIV-1 integrase strand transfer inhibitor (InSTI) dolutegravir (DTG) has had a major impact on the treatment of HIV-1 infection. Here we describe important but previously undetermined pharmacodynamic parameters for DTG. We show that the dose-response curve slope, which indicates cooperativity and is a major determinant of antiviral activity, is higher for DTG than for first-generation InSTIs. This steepness does not reflect inhibition of multiple steps in the HIV-1 life cycle, as is the case for allosteric integrase inhibitors and HIV-1 protease inhibitors. We also show that degree of independence, a metric of interaction favorability between antiretroviral drugs, is high for DTG and nucleoside reverse transcriptase inhibitors. Finally, we demonstrate poor selective advantage for HIV-1 bearing InSTI resistance mutations. Selective advantage, which incorporates both the magnitude of resistance conferred by a mutation and its fitness cost, explains the high genetic barrier to DTG resistance. Together, these parameters provide an explanation for the remarkable clinical success of DTG.

Integrase Strand Transfer Inhibitors (INSTIs) Resistance Mutations in HIV-1 Infected Turkish Patients

Objectives: Integrase strand transfer inhibitor (INSTI) is a new class of antiretroviral (ARV) drugs designed to block the action of the integrase viral enzyme, which is responsible for insertation of the HIV-1 genome into the host DNA. The aim of this study was to evaluate for the first time INSTI resistance mutations in Turkish patients.Methods: This study was conducted in Turkey, between April 2013 and April 2015 using 169 HIV-1-infected patients (78 ARV naive patients and 91 ARV-experienced patients). Laboratory and clinical characteristics of ARV naive and ARV-experienced patients were as follows: gender (M/F): 71/7 and 80/11, median age: 38 and 38.4; median CD4+ T-cell: 236 and 216 cells/mm3, median HIV-1 RNA: 4.95+E5 and 1.08E+6 copies/ml. Population-based seqeunces of the reverse transcriptase, protease, and integrase domains of the HIV-1 pol gene were used to detect HIV-1 drug resistance mutations.Result: INSTI resistance mutations were not found in recently diagnosed HIV-1-infected patients. However, ARV-experienced patients had major resistance mutations associated with raltegravir and elvitegravir; the following results were generated:F121Y, Y143R, Q148R and E157Q (6/91 – 6.6%).Conclusions: The prevalence of INSTI resistant mutations in ART-experienced patients suggested that resistance testing must be incorporated as an integral part of HIV management with INSTI therapies.