Drug resistance mutations of HIV type 1 non-B viruses to integrase inhibitors in treatment-naive patients from sub-saharan countries and discordant interpretations

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

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

HIV-1 integrase resistance associated mutations and the use of dolutegravir in Sub-Saharan Africa: A systematic review and meta-analysis

As sub-Saharan Africa (SSA) countries are transitioning to dolutegravir (DTG)-based ART, baseline data are required for optimal monitoring of therapeutic response. In this frame, we sought to generate up-to-date evidence on the use of integrase-strand transfer inhibitors (INSTI) and associated drug resistance mutations (DRMs) within SSA. In this systematic review and meta-analysis, we included randomized and non-randomized trials, cohort-studies, cross-sectional studies, and case-reports published on INSTI or integrase DRMs in SSA. We included studies of patients exposed to DTG, raltegravir (RAL) or elvitegravir (EVG). Primary outcomes were "the rate of virological control (VC:<50copies/ml)" and "the presence of DRMs" on INSTI-based regimens among patients in SSA. We synthesised extracted data using subgroup analysis, and random effect models were used where appropriate. Additional analyses were conducted to assess study heterogeneity. We identified 1,916 articles/citations through database searches, of which 26 were included in the analysis pertaining to 5,444 patients (mean age: 37±13 years), with 67.62% (3681/5444) female. Specifically, 46.15% (12/26) studies focused on DTG, 26.92% (7/26) on RAL, 23.08% (6/26) on both DTG and RAL, and 3.85% (1/26) on EVG. We found an increasing use of DTG overtime (0% before 2018 to 100% in 2021). Median treatment duration under INSTI-based regimens was 12 [9-36] months. Overall, the rate of VC was 88.51% [95%CI: 73.83-97.80] with DTG vs. 82.49% [95%CI: 55.76-99.45] and 96.55% [95%CI: 85.7-100.00] with RAL and EVG, respectively. In univariate analysis, VC with DTG-containing vs. other INSTI-regimens was significantly higher (OR = 1.44 [95%CI: 1.15-1.79], p = 0.0014). Among reported DRMs at failure, the only DTG resistance-mutations were G118R and R263K. In SSA, DTG presents a superiority effect in VC compared to other INSTIs. Nonetheless, the early detection of INSTI-DRMs calls for sentinel surveillance for a successful transition and a sustained efficacy of DTG in SSA. PROSPERO Registration Number: CRD42019122424.

Baseline integrase drug resistance mutations and conserved regions across HIV-1 clades in Cameroon: implications for transition to dolutegravir in resource-limited settings

BACKGROUND

Transition to dolutegravir-based regimens in resource-limited settings (RLS) requires prior understanding of HIV-1 integrase variants and conserved regions. Therefore, we evaluated integrase drug resistance mutations (DRMs) and conserved regions amongst integrase strand transfer inhibitor (INSTI)-naive patients harbouring diverse HIV-1 clades in Cameroon.

METHODS

A cross-sectional study was conducted amongst 918 INSTI-naive patients from Cameroon (89 ART-naive and 829 ART-experienced patients). HIV-1 sequences were interpreted regarding INSTI-DRMs using the Stanford HIVdb v8.9-1 and the 2019 IAS-USA list. Amino acid positions with <1% variability were considered as highly conserved. Subtyping was performed by phylogeny.

RESULTS

Overall prevalence (95% CI) of INSTI-DRMs was 0.8% (0.4-1.7), with 0.0% (0.0-4.0) amongst ART-naive versus 0.9% (0.5-1.9) amongst ART-experienced patients; P = 0.44. Accessory mutations (95% CI) were found in 33.8% (30.9-37.0), with 38.2% (28.1-49.1) amongst ART-naive versus 33.4% (30.4-36.7) amongst ART-experienced patients; P = 0.21. Of 288 HIV-1 integrase amino acid positions, 58.3% were highly conserved across subtypes in the following major regions: V75-G82, E85-P90, H114-G118, K127-W132, E138-G149, Q168-L172, T174-V180, W235-A239 and L241-D253. Wide genetic diversity was found (37 clades), including groups M (92.3%), N (1.4%), O (6.2%) and P (0.1%). Amongst group M, CRF02_AG was predominant (47.4%), with a significantly higher frequency (95% CI) of accessory mutations compared with non-AG [41.4% (36.8-46.0) versus 27.1% (23.3-31.2) respectively; P < 0.001].

CONCLUSIONS

The low baseline of INSTI-DRMs (<1%) in Cameroon suggests effectiveness of dolutegravir-based regimens. In spite of high conservation across clades, the variability of accessory mutations between major circulating strains underscores the need for monitoring the selection of INSTI-DRMs while scaling up dolutegravir-based regimens in RLS.

High predictive efficacy of integrase strand transfer inhibitors in perinatally HIV-1-infected African children in therapeutic failure of first- and second-line antiretroviral drug regimens recommended by the WHO

Objectives

The predictive efficacy of integrase (IN) strand transfer inhibitors (INSTIs) was investigated in HIV-infected children born to HIV-infected mothers in Africa.

Methods

Plasma was collected at the Complexe Pédiatrique of Bangui, Central African Republic, from INSTI-naive children (n = 8) and adolescents (n = 10) in virological failure (viral load >1000 copies/mL) after 5 years of first- and/or second-line combination ART (cART). IN, reverse transcriptase (RT) and protease (P) genes were genotyped and drug resistance mutations (DRMs) to INSTIs, NRTIs, NNRTIs and PIs were interpreted using the Stanford algorithm.

Results

Successful IN, RT and P genotypes were obtained for 18, 13 and 15 children (median age 11 years, range 5–18; 8 were female), respectively. Two (2/18; 11.1%) viruses from children treated with a first-line regimen had INSTI DRMs at codon 138 (E138K and E138T), which is known to harbour major resistance mutations, and also had the accessory mutations L74I, G140K, G140R and G163R. The majority (16/18; 88.9%) of HIV-1 IN sequences demonstrated full susceptibility to all major INSTIs with a high frequency of natural polymorphic mutations. Most (12/15; 80%) genotyped viruses harboured at least one major DRM conferring resistance to at least one of the WHO-recommended antiretroviral drugs (NNRTIs, NRTIs and PIs) prescribed in first- and second-line regimens.

Conclusions

INSTIs could be proposed in first-line regimens in the majority of African children or adolescents and may constitute relevant therapeutic alternatives as second- and third-line cART regimens in HIV-infected children and adolescents living in sub-Saharan Africa.

Absence of Integrase Strand Transfer Inhibitor Associated Resistance in Antiretroviral Therapy Naïve and Experienced Individuals from Western India

The Indian national AIDS control program heavily relies on low cost nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI). With global increase in resistance to these, alternative antiretroviral combinations need to be explored. Owing to higher potency, better efficacy and tolerability, recently WHO recommended integrase strand transfer inhibitor (INSTI) based first-line antiretroviral therapy (ART). There is lack of INSTI resistance surveillance data from India. Thus, there is a need to analyze integrase (IN) gene from primarily HIV-1 subtype C infected Indian population, before widespread introduction of INSTI in first-line ART. Plasma samples were collected from INSTI naïve individuals reporting to ART centre of Pune, India. RNA was extracted and IN gene was amplified by nested polymerase chain reaction (PCR) using prior published primers. PCR product of 867 bp was bi-directionally sequenced and resistance associated mutation were analyzed using Stanford University HIV drug resistance algorithm. A total of 58 HIV-1 sequences from 62 INSTI naïve individuals were successfully genotyped. Of these 58, 40 were ART naïve, newly diagnosed and remaining individuals were on NRTI, NNRTI, or protease inhibitors based failing regimen. The commonest subtype identified in the study was C (93%) followed by A1 (3.5%). A total of 191 (66.31%) fully conserved amino acid (aa) positions were observed in IN gene. Overall there was absence of major INSTI resistance mutation, however, E157Q (13.79%) emerged as common polymorphic mutation. Other accessory mutations were L74IM (34.48%), Q95K (1.72%), and T97A (1.72%). To conclude, this first Indian study on primarily HIV-1 subtype C sequences characterized aa variations in IN gene and indicated absence of major INSTI resistance associated mutations.

Prevalence of resistance to integrase strand-transfer inhibitors (INSTIs) among untreated HIV-1 infected patients in Morocco

Objective

The integrase strand-transfer inhibitors (INSTIs) are an important class in the arsenal of antiretroviral drugs designed to block the integration of HIV-1 cDNA into the host DNA through the inhibition of DNA strand transfer. In this study for the first time in Morocco, the complete HIV-1 integrase gene was analysed from newly diagnosed patients to evaluate the prevalence of natural polymorphisms and INSTIs resistance-associated mutations in the integrase gene.

Results

The 864pb IN coding region was successfully sequenced from plasma sample for 77 among 80 antiretroviral naïve patients. The sequences were interpreted for drug resistance according to the Stanford algorithm. Sixty samples were HIV-1 subtype B (78%), fourteen CRF02_AG (18%), two subtype C and one subtype A. Overall 81 of 288 (28%) amino acid IN positions presented at least one polymorphism each. We found 18 (36.73%), 42 (25.76%) and 21 (27.27%) of polymorphic residues assigned to the N-Terminal Domain, Catalytic Core Domaine and the C-Terminal Domain positions respectively. Primary INSTIs resistance mutation were absent, however secondary mutations L74IM, T97A were detected in four samples (5.2%). These results demonstrate that untreated HIV-1 infected Moroccans will be susceptible to INSTIs.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3492-5) contains supplementary material, which is available to authorized users.

Lack of impact of pre-existing T97A HIV-1 integrase mutation on integrase strand transfer inhibitor resistance and treatment outcome

T97A is an HIV-1 integrase polymorphism associated with integrase strand transfer inhibitor (INSTI) resistance. Using pooled data from 16 clinical studies, we investigated the prevalence of T97A (pre-existing and emergent) and its impact on INSTI susceptibility and treatment response in INSTI-naive patients who enrolled on elvitegravir (EVG)- or raltegravir (RAL)-based regimens. Prior to INSTI-based therapy, primary INSTI resistance-associated mutations (RAMs) were absent and T97A pre-existed infrequently (1.4%; 47 of 3367 integrase sequences); most often among non-B (5.3%) than B (0.9%) HIV-1 subtypes. During INSTI-based therapy, few patients experienced virologic failure with emergent INSTI RAMs (3%; 122 of 3881 patients), among whom T97A emerged infrequently in the presence (n = 6) or absence (n = 8) of primary INSTI RAMs. A comparison between pre-existing and emergent T97A patient populations (i.e., in the absence of primary INSTI RAMs) showed no significant differences in EVG or RAL susceptibility in vitro. Furthermore, among all T97A-containing viruses tested, only 38-44% exhibited reduced susceptibility to EVG and/or RAL (all of low magnitude; <11-fold), while all maintained susceptibility to dolutegravir. Of the patients with pre-existing T97A, 17 had available clinical follow-up: 16 achieved virologic suppression and 1 maintained T97A and INSTI sensitivity without further resistance development. Overall, T97A is an infrequent integrase polymorphism that is enriched among non-B HIV-1 subtypes and can confer low-level reduced susceptibility to EVG and/or RAL. However, detection of T97A does not affect response to INSTI-based therapy with EVG or RAL. These results suggest a very low risk of initiating INSTI-based therapy in patients with pre-existing T97A.

Use of Integrase Inhibitors in HIV-Infected Children and Adolescents

Resistance to antiretroviral drugs is an increasingly prevalent challenge affecting both the adult and pediatric HIV-infected populations. Though data on the safety, pharmacokinetics, and efficacy of newer antiretroviral agents in children typically lags behind adult data, newer agents are becoming available for use in HIV-infected children who are failing to respond to or are experiencing toxicities with traditional antiretroviral regimens. Integrase strand transfer inhibitors are one such new class of antiretrovirals. Raltegravir has been US Food and Drug Administration (FDA) approved for use in patients over the age of 4 weeks. Elvitegravir is a second member of this class, and has the potential for use in children but does not yet have a Pediatric FDA indication. Dolutegravir, a second-generation integrase inhibitor, is approved for those older than 12 years. This review summarizes the use of integrase inhibitors in children and adolescents, and highlights the results of recent clinical trials.

Mutagenesis of Lysines 156 and 159 in Human Immunodeficiency Virus Type 1 Integrase (IN) Reveals Differential Interactions between these Residues and Different IN Inhibitors

Human immunodeficiency virus (HIV) type 1 integrase (IN) active site, and viral DNA-binding residues K156 and K159 are predicted to interact both with strand transfer-selective IN inhibitors (STI), e.g. L-731,988, Elvitegravir (EVG), and the FDA-approved IN inhibitor, Raltegravir (RGV), and strand transfer non-selective inhibitors, e.g. dicaffeoyltartaric acids (DCTAs), e.g. L-chicoric acid (L-CA). To test posited roles for these two lysine residues in inhibitor action we assayed the potency of L-CA and several STI against a panel of K156 and K159 mutants. Mutagenesis of K156 conferred resistance to L-CA and mutagenesis of either K156 or K159 conferred resistance to STI indicating that the cationic charge at these two viral DNA-binding residues is important for inhibitor potency. IN K156N, a reported polymorphism associated with resistance to RGV, conferred resistance to L-CA and STI as well. To investigate the apparent preference L-CA exhibits for interactions with K156, we assayed the potency of several hybrid inhibitors containing combinations of DCTA and STI pharmacophores against recombinant IN K156A or K159A. Although K156A conferred resistance to diketo acid-branched bis-catechol hybrid inhibitors, neither K156A nor K159A conferred resistance to their monocatechol counterparts, suggesting that bis-catechol moieties direct DCTAs toward K156. In contrast, STI were more promiscuous in their interaction with K156 and K159. Taken together, the results of this study indicate that DCTAs interact with IN in a manner different than that of STI and suggest that DCTAs are an attractive candidate chemotype for development into drugs potent against STI-resistant IN.

Consensus HIV-1 subtype A integrase and its raltegravir-resistant variants: design and characterization of the enzymatic properties

Model studies of the subtype B and non-subtype B integrases are still required to compare their susceptibility to antiretroviral drugs, evaluate the significance of resistance mutations and identify the impact of natural polymorphisms on the level of enzymatic reactivity. We have therefore designed the consensus integrase of the HIV-1 subtype A strain circulating in the former Soviet Union territory (FSU-A) and two of its variants with mutations of resistance to the strand transfer inhibitor raltegravir. Their genes were synthesized, and expressed in E coli; corresponding His-tagged proteins were purified using the affinity chromatography. The enzymatic properties of the consensus integrases and their sensitivity to raltegravir were examined in a series of standard in vitro reactions and compared to the properties of the integrase of HIV-1 subtype B strain HXB2. The consensus enzyme demonstrated similar DNA-binding properties, but was significantly more active than HXB-2 integrase in the reactions of DNA cleavage and integration. All integrases were equally susceptible to inhibition by raltegravir and elvitegravir, indicating that the sporadic polymorphisms inherent to the HXB-2 enzyme have little effect on its susceptibility to drugs. Insensitivity of the mutated enzymes to the inhibitors of strand transfer occurred at a cost of a 30-90% loss of the efficacies of both 3'-processing and strand transfer. This is the first study to describe the enzymatic properties of the consensus integrase of HIV-1 clade A and the effects of the resistance mutations when the complex actions of sporadic sequence polymorphisms are excluded.

HIV-1 Genetic Variability and Clinical Implications

Despite advances in antiretroviral therapy that have revolutionized HIV disease management, effective control of the HIV infection pandemic remains elusive. Beyond the classic non-B endemic areas, HIV-1 non-B subtype infections are sharply increasing in previous subtype B homogeneous areas such as Europe and North America. As already known, several studies have shown that, among non-B subtypes, subtypes C and D were found to be more aggressive in terms of disease progression. Luckily, the response to antiretrovirals against HIV-1 seems to be similar among different subtypes, but these results are mainly based on small or poorly designed studies. On the other hand, differences in rates of acquisition of resistance among non-B subtypes are already being observed. This different propensity, beyond the type of treatment regimens used, as well as access to viral load testing in non-B endemic areas seems to be due to HIV-1 clade specific peculiarities. Indeed, some non-B subtypes are proved to be more prone to develop resistance compared to B subtype. This phenomenon can be related to the presence of subtype-specific polymorphisms, different codon usage, and/or subtype-specific RNA templates. This review aims to provide a complete picture of HIV-1 genetic diversity and its implications for HIV-1 disease spread, effectiveness of therapies, and drug resistance development.

Genetic Analysis of HIV-1 Integrase Sequences from Treatment Naive Individuals in Northeastern South Africa

Raltegravir, an integrase inhibitor, is not a component of the current South African antiretroviral treatment guidelines, but it could be introduced in the near future as cases of virological failures from current treatment regimens begin to occur. The aim of this study was to analyze the complete HIV integrase gene obtained from individuals at two treatment sites in northeastern South Africa for the presence of Raltegravir associated drug resistant mutations and viral subtypes based on the integrase gene. Examination for mutations against other integrase inhibitors, such as Elvitegravir and Dolutegravir, was also done. Viruses from 127 treatment naive individuals were analyzed. Genetic drug resistance mutations were determined using the Stanford HIV Drug Resistance Interpretation program and the International AIDS society-USA guidelines. Viral subtyping was done by phylogenetic analysis, and recombinants were determined using the REGA, jpHMM and RIP tools. No major resistance mutations were detected. However, 7% of the sequences had minor mutations and polymorphisms. The majority (99%) of the viruses were HIV-1 C. Recombination analysis showed that the polymerase gene of one virus was likely composed of HIV-1 subtype A1 and C sequences. The present study indicates that Raltegravir, Elvitegravir and Dolutegravir resistant mutations may be absent in the study communities and further indicates the presence of recombinant viruses in northeastern South Africa.

HIV-1 integrase resistance among antiretroviral treatment naive and experienced patients from Northwestern Poland

Background

HIV integrase inhibitor use is limited by low genetic barrier to resistance and possible cross-resistance among representatives of this class of antiretrovirals. The aim of this study was to analyse integrase sequence variability among antiretroviral treatment naive and experienced patients with no prior integrase inhibitor (InI) exposure and investigate development of the InI drug resistance mutations following the virologic failure of the raltegravir containing regimen.

Methods

Sequencing of HIV-1 integrase region from plasma samples of 80 integrase treatment naive patients and serial samples from 12 patients with observed virologic failure on raltegravir containing treatment whenever plasma vireamia exceeded >50 copies/ml was performed. Drug resistance mutations were called with Stanford DB database and grouped into major and minor variants. For subtyping bootstrapped phylogenetic analysis was used; Bayesian Monte Carlo Marcov Chain (MCMC) model was implemented to infer on the phylogenetic relationships between the serial sequences from patients failing on raltegravir.

Results

Majority of the integrase region sequences were classified as subtype B; the remaining ones being subtype D, C, G, as well as CRF01_AE , CRF02_AG and CRF13_cpx recombinants. No major integrase drug resistance mutations have been observed in InI-treatment naive patients. In 30 (38.5%) cases polymorphic variation with predominance of the E157Q mutation was observed. This mutation was more common among subtype B (26 cases, 54.2%) than non-B sequences (5 cases, 16.7%), p=0.00099, OR: 5.91 (95% CI:1.77-22.63)]. Other variants included L68V, L74IL, T97A, E138D, V151I, R263K. Among 12 (26.1%) raltegravir treated patients treatment failure was observed; major InI drug resistance mutations (G140S, Q148H and N155H, V151I, E92EQ, V151I, G163R) were noted in four of these cases (8.3% of the total InI-treated patients). Time to the development of drug resistance ranged from 2.6 to 16.3 months with mean increase of HIV viral load of 4.34 (95% CI:1.86-6.84) log HIV-RNA copies/ml at the time of emergence of the major mutations. Baseline polymorphisms, including E157Q were not associated with the virologic failure on raltegravir.

Conclusions

In InI treatment naive patients polymorphic integrase sequence variation was common, with no major resistance mutants. In the treatment failing patients selection of drug resistance occurred rapidly and followed the typical drug resistance pathways. Preexisting integrase polymorphisms were not associated with the treatment failure.