Low-frequency HIV-1 drug resistance mutations and risk of NNRTI-based antiretroviral treatment failure: a systematic review and pooled analysis

Virologic outcomes with tenofovir-lamivudine-dolutegravir in adults failing PI-based second-line ART

Background

In South African antiretroviral guidelines, selected patients failing second-line protease inhibitor (PI)-based therapy qualify for genotypic resistance testing - those with PI resistance receive darunavir-based third-line regimens; those without PI resistance continue current regimen with adherence support. The Western Cape province, from September 2020, implemented a strategy of tenofovir-lamivudine-dolutegravir (TLD) for patients, provided there was no tenofovir resistance, irrespective of PI resistance.

Objectives

To evaluate virologic outcomes with TLD among adults failing second-line PI regimens with no tenofovir resistance.

Method

An observational cohort study comparing outcomes in patients switched to TLD with those continuing the same PI or switched to darunavir-based regimens. Follow-up was until virologic suppression (HIV-1 RNA < 400 copies/mL), or at the point of censoring.

Results

One hundred and thirty-three patients switched to TLD, 101 to darunavir-based regimens, and 121 continued with the same PI. By 12 months, among patients with PI resistance, 42/47 (89%) in the TLD group had HIV-1 RNA < 400 copies/mL compared to 91/99 (92%) in the darunavir group (hazard ratio, 1.11; 95% confidence interval, 0.77-1.60). In patients without PI resistance, 66/86 (77%) in the TLD group had HIV-1 RNA < 400 copies/mL compared to 42/120 (35%) in those continuing with the same PI (hazard ratio, 4.03; 95% confidence interval, 2.71-5.98). Two patients receiving TLD developed virologic failure with high-level dolutegravir resistance.

Conclusion

Amongst patients failing second-line PI with no PI resistance, switching to TLD was associated with higher virologic suppression, likely due to improved adherence. Virologic outcomes were similar in patients with PI resistance switched to darunavir-based regimens or TLD.

Enhanced Detection of Novel Low-Frequency Gene Fusions via High-Yield Ligation and Multiplexed Enrichment Sequencing

Panel-based methods are commonly employed for the analysis of novel gene fusions in precision diagnostics and new drug development in cancer. However, these methods are constrained by limitations in ligation yield and the enrichment of novel gene fusions with low variant allele frequencies. In this study, we conducted a pioneering investigation into the stability of double-stranded adapter DNA, resulting in improved ligation yield and enhanced conversion efficiency. Additionally, we implemented blocker displacement amplification, achieving a remarkable 7-fold enrichment of novel gene fusions. Leveraging the pre-enrichment achieved with this approach, we successfully applied it to Nanopore sequencing, enabling ultra-fast analysis of novel gene fusions within one hour with high sensitivity. This method offers a robust and remarkably sensitive mean of analyzing novel gene fusions, promising the discovery of pivotal biomarkers that can significantly improve cancer diagnostics and the development of new therapeutic strategies.

HIV-1 Drug Resistance Detected by Next-Generation Sequencing among ART-Naïve Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

There are an increasing number of articles focused on the prevalence and clinical impact of pretreatment HIV drug resistance (PDR) detected by Sanger sequencing (SGS). PDR may contribute to the increased likelihood of virologic failure and the emergence of new resistance mutations. As SGS is gradually replaced by next-generation sequencing (NGS), it is necessary to assess the levels of PDR using NGS in ART-naïve patients systematically. NGS can detect the viral variants (low-abundance drug-resistant HIV-1 variants (LA-DRVs)) of virus quasi-species at levels below 20% that SGS may fail to detect. NGS has the potential to optimize current HIV drug resistance surveillance methods and inform future research directions. As the NGS technique has high sensitivity, it is highly likely that the level of pretreatment resistance would be underestimated using conventional techniques.

METHODS

For the systematic review and meta-analysis, we searched for original studies published in PubMed, Web of Science, Scopus, and Embase before 30 March 2023 that focused exclusively on the application of NGS in the detection of HIV drug resistance. Pooled prevalence estimates were calculated using a random effects model using the 'meta' package in R (version 4.2.3). We described drug resistance detected at five thresholds (>1%, 2%, 5%, 10%, and 20% of virus quasi-species). Chi-squared tests were used to analyze differences between the overall prevalence of PDR reported by SGS and NGS.

RESULTS

A total of 39 eligible studies were selected. The studies included a total of 15,242 ART-naïve individuals living with HIV. The prevalence of PDR was inversely correlated with the mutation detection threshold. The overall prevalence of PDR was 29.74% at the 1% threshold, 22.43% at the 2% threshold, 15.47% at the 5% threshold, 12.95% at the 10% threshold, and 11.08% at the 20% threshold. The prevalence of PDR to INSTIs was 1.22% (95%CI: 0.58-2.57), which is the lowest among the values for all antiretroviral drugs. The prevalence of LA-DRVs was 9.45%. At the 2% and 20% detection threshold, the prevalence of PDR was 22.43% and 11.08%, respectively. Resistance to PIs and INSTIs increased 5.52-fold and 7.08-fold, respectively, in those with a PDR threshold of 2% compared with those with PDR at 20%. However, resistance to NRTIs and NNRTIs increased 2.50-fold and 2.37-fold, respectively. There was a significant difference between the 2% and 5% threshold for detecting HIV drug resistance. There was no statistically significant difference between the results reported by SGS and NGS when using the 20% threshold for reporting resistance mutations.

CONCLUSION

In this study, we found that next-generation sequencing facilitates a more sensitive detection of HIV-1 drug resistance than SGS. The high prevalence of PDR emphasizes the importance of baseline resistance and assessing the threshold for optimal clinical detection using NGS.

Rate of response to initial antiretroviral therapy according to level of pre-existing HIV-1 drug resistance detected by next-generation sequencing in the strategic timing of antiretroviral treatment (START) study

OBJECTIVES

The main objective of this analysis was to evaluate the impact of pre-existing drug resistance by next-generation sequencing (NGS) on the risk of treatment failure (TF) of first-line regimens in participants enrolled in the START study.

METHODS

Stored plasma from participants with entry HIV RNA >1000 copies/mL were analysed using NGS (llumina MiSeq). Pre-existing drug resistance was defined using the mutations considered by the Stanford HIV Drug Resistance Database (HIVDB v8.6) to calculate the genotypic susceptibility score (GSS, estimating the number of active drugs) for the first-line regimen at the detection threshold windows of >20%, >5%, and >2% of the viral population. Survival analysis was conducted to evaluate the association between the GSS and risk of TF (viral load >200 copies/mL plus treatment change).

RESULTS

Baseline NGS data were available for 1380 antiretroviral therapy (ART)-naïve participants enrolled over 2009-2013. First-line ART included a non-nucleoside reverse transcriptase inhibitor (NNRTI) in 976 (71%), a boosted protease inhibitor in 297 (22%), or an integrase strand transfer inhibitor in 107 (8%). The proportions of participants with GSS <3 were 7% for >20%, 10% for >5%, and 17% for the >2% thresholds, respectively. The adjusted hazard ratio of TF associated with a GSS of 0-2.75 versus 3 in the subset of participants with mutations detected at the >2% threshold was 1.66 (95% confidence interval 1.01-2.74; p = 0.05) and 2.32 (95% confidence interval 1.32-4.09; p = 0.003) after restricting the analysis to participants who started an NNRTI-based regimen.

CONCLUSIONS

Up to 17% of participants initiated ART with a GSS <3 on the basis of NGS data. Minority variants were predictive of TF, especially for participants starting NNRTI-based regimens.

Impact of pretreatment low-abundance HIV-1 drug resistance on virological failure after 1 year of antiretroviral therapy in China

OBJECTIVES

To assess the impact of pretreatment low-abundance HIV drug-resistant variants (LA-DRVs) on virological outcomes among ART-naive HIV-1-infected Chinese people who initiated ART.

METHODS

A nested case-control study was conducted among HIV-1-infected individuals who had pretreatment drug resistance (PDR) genotypic results. Cases were defined as individuals with virological failure (HIV-1 RNA viral load ≥1000 copies/mL) after 1 year of ART, and controls were individuals from the same cohort whose viral load was less than 1000 copies/mL. Next-generation sequencing was used to identify low-abundance PDR mutations at detection thresholds of 10%, 2% and 1%. The mutant load was calculated by multiplying the abundance of HIV-1 drug-resistant variants by the pretreatment viral load. The impact of pretreatment low-abundance mutations on virological failure was estimated in logistic regression models.

RESULTS

Participants (43 cases and 100 controls) were included in this study for the analysis. The proportion of participants with PDR was higher in cases than in controls at different detection thresholds (44.2% versus 22.0%, P = 0.007 at 10% threshold; 58.1% versus 31.0%, P = 0.002 at 2% threshold; 90.7% versus 69.0%, P = 0.006 at 1% threshold). Compared with participants without PDR, participants with ≥10% detectable PDR mutations were associated with an increased risk of virological failure (adjusted OR 8.0, 95% CI 2.4-26.3, P = 0.001). Besides this, individuals with pretreatment LA-DRVs (2%-9% abundance range) had 5-fold higher odds of virological failure (adjusted OR 5.0, 95% CI 1.3-19.6, P = 0.021). Furthermore, LA-DRVs at 2%-9% abundance resistant to NRTIs and mutants with abundance of ≥10% resistant to NNRTIs had a 4-fold and 8-fold risk of experiencing virological failure, respectively. It was also found that a mutant load of more than 1000 copies/mL was predictive of virological failure (adjusted OR 7.2, 95% CI 2.5-21.1, P = 0.0003).

CONCLUSIONS

Low-abundance PDR mutations ranging from 2% to 9% of abundance can increase the risk of virological failure. Further studies are warranted to define a clinically relevant threshold of LA-DRVs and the role of NRTI LA-DRVs.

Need assessment for HIV drug resistance testing and landscape of current and future technologies in low- and middle-income countries

Resistance to antiretroviral drugs used to treat HIV is an important and evolving concern, particularly in low- and middle-income countries (LMICs) which have been impacted to the greatest extent by the HIV pandemic. Efforts to monitor the emergence and transmission of resistance over the past decade have shown that drug resistance-especially to the nucleoside analogue and non-nucleoside reverse transcriptase inhibitors-can (and have) increased to levels that can jeopardize the efficacy of available treatment options at the population level. The global shift to integrase-based regimens as the preferred first-line therapy as well as technological advancements in the methods for detecting resistance have had an impact in broadening and diversifying the landscape of and use case for HIV drug resistance testing. This review estimates the potential demand for HIV drug resistance tests, and surveys current testing methodologies, with a focus on their application in LMICs.

Sensitive HIV-1 DNA Pol Next-Generation Sequencing for the Characterisation of Archived Antiretroviral Drug Resistance

Modern HIV-1 treatment effectively suppresses viral amplification in people living with HIV. However, the persistence of HIV-1 DNA as proviruses integrated into the human genome remains the main barrier to achieving a cure. Next-generation sequencing (NGS) offers increased sensitivity for characterising archived drug resistance mutations (DRMs) in HIV-1 DNA for improved treatment options. In this study, we present an ultra-sensitive targeted PCR assay coupled with NGS and a robust pipeline to characterise HIV-1 DNA DRMs from buffy coat samples. Our evaluation supports the use of this assay for Pan-HIV-1 analyses with reliable detection of DRMs across the HIV-1 Pol region. We propose this assay as a new valuable tool for monitoring archived HIV-1 drug resistance in virologically suppressed individuals, especially in clinical trials investigating novel therapeutic approaches.

HIV-1 Low-Frequency Variants Identified in Antiretroviral-Naïve Subjects with Virologic Failure after 12 Months of Follow-Up in Panama

Low-frequency mutations associated with drug resistance have been related to virologic failure in subjects with no history of pre-treatment and recent HIV diagnosis. In total, 78 antiretroviral treatment (ART)-naïve subjects with a recent HIV diagnosis were selected and followed by CD4+ T lymphocytes and viral load tests to detect virologic failure. We sequenced the basal samples retrospectively using next-generation sequencing (NGS), looking for low-frequency mutations that had not been detected before using the Sanger sequencing method (SSM) and describing the response to ART. Twenty-two subjects developed virologic failure (VF), and thirteen of them had at least one drug-resistance mutation associated with Reverse Transcriptase Inhibitors (RTI) and Protease Inhibitors (PIs) at frequency levels ≤ 1%, not detected previously in their basal genotyping test. No resistance mutations were observed to Integrase Strand Transfer Inhibitors (INSTIs). We identified a possible cause of VF in ART-naïve subjects with low-frequency mutations detected. To our knowledge, this is the first evaluation of pre-existing drug resistance for HIV-1 minority variants carried out on ART-naïve people living with HIV/AIDS (PLWHA) by analyzing the HIV-1 pol gene using NGS in the country.

Added Value of Next Generation Sequencing in Characterizing the Evolution of HIV-1 Drug Resistance in Kenyan Youth

Drug resistance remains a global challenge in children and adolescents living with HIV (CALWH). Characterizing resistance evolution, specifically using next generation sequencing (NGS) can potentially inform care, but remains understudied, particularly in antiretroviral therapy (ART)-experienced CALWH in resource-limited settings. We conducted reverse-transcriptase NGS and investigated short-and long-term resistance evolution and its predicted impact in a well-characterized cohort of Kenyan CALWH failing 1st-line ART and followed for up to ~8 years. Drug resistance mutation (DRM) evolution types were determined by NGS frequency changes over time, defined as evolving (up-trending and crossing the 20% NGS threshold), reverting (down-trending and crossing the 20% threshold) or other. Exploratory analyses assessed potential impacts of minority resistance variants on evolution. Evolution was detected in 93% of 42 participants, including 91% of 22 with short-term follow-up, 100% of 7 with long-term follow-up without regimen change, and 95% of 19 with long-term follow-up with regimen change. Evolving DRMs were identified in 60% and minority resistance variants evolved in 17%, with exploratory analysis suggesting greater rate of evolution of minority resistance variants under drug selection pressure and higher predicted drug resistance scores in the presence of minority DRMs. Despite high-level pre-existing resistance, NGS-based longitudinal follow-up of this small but unique cohort of Kenyan CALWH demonstrated continued DRM evolution, at times including low-level DRMs detected only by NGS, with predicted impact on care. NGS can inform better understanding of DRM evolution and dynamics and possibly improve care. The clinical significance of these findings should be further evaluated.

HIV-1 resistance genotyping by ultra-deep sequencing and 6-month virological response to first-line treatment

OBJECTIVES

To evaluate the routine use of the Sentosa ultra-deep sequencing (UDS) system for HIV-1 polymerase resistance genotyping in treatment-naïve individuals and to analyse the virological response (VR) to first-line antiretroviral treatment.

METHODS

HIV drug resistance was determined on 237 consecutive samples from treatment-naïve individuals using the Sentosa UDS platform with two mutation detection thresholds (3% and 20%). VR was defined as a plasma HIV-1 virus load <50 copies/mL after 6 months of treatment.

RESULTS

Resistance to at least one antiretroviral drug with a mutation threshold of 3% was identified in 29% and 16% of samples according to ANRS and Stanford algorithms, respectively. The ANRS algorithm also revealed reduced susceptibility to at least one protease inhibitor (PI) in 14.3% of samples, to one reverse transcriptase inhibitor in 12.7%, and to one integrase inhibitor (INSTI) in 5.1%. For a mutation threshold of 20%, resistance was identified in 24% and 13% of samples according to ANRS and Stanford algorithms, respectively. The 6 months VR was 87% and was similar in the 58% of patients given INSTI-based treatment, in the 16% given PI-based treatment and in the 9% given NNRTI-based treatment. Multivariate analysis indicated that the VR was correlated with the baseline HIV virus load and resistance to at least one PI at both 3% and 20% mutation detection thresholds (ANRS algorithm).

CONCLUSIONS

The Vela UDS platform is appropriate for determining antiretroviral resistance in patients on a first-line antiretroviral treatment. Further studies are needed on the use of UDS for therapeutic management.

In Vitro Susceptibility of HIV Isolates with High Growth Capability to Antiretroviral Drugs

It has been considered that reduced susceptibility to antiretroviral drugs is influenced by drug adherence, drug tolerance and drug-resistance-related mutations in the HIV genome. In the present study, we assessed the intrinsic high viral growth capability as a potential viral factor that may influence their susceptibility to antiretroviral drugs using an in vitro model. Phytohemagglutinin-activated peripheral blood mononuclear cells (1.5 × 10⁶ cells) were infected with HIV isolates (10⁶ copies/mL). The culture was carried out at different concentrations (0.001-20 μM) of 13 synthetic antiretroviral compounds (six nucleoside/nucleotide reverse transcriptase inhibitors, one non-nucleoside reverse transcriptase inhibitor, four integrase inhibitors, and two protease inhibitors), and HIV production was assessed using HIV-RNA copies in culture. The 90% inhibitory concentration (IC₉₀) and pharmacokinetics of an antiretroviral agent were used as parameters to determine the reduced antiretroviral drug susceptibility of HIV isolates with high growth capability to synthetic antiretroviral compounds. The high growth capability of HIV isolates without any known drug resistance-related mutation affected their susceptibility to tenofovir (IC₉₀ = 2.05 ± 0.40 μM), lamivudine (IC₉₀ = 6.83 ± 3.96 μM), emtricitabine (IC₉₀ = 0.68 ± 0.37 μM), and efavirenz (IC₉₀ = 3.65 ± 0.77 μM). These antiretroviral drugs showed IC₉₀ values close to or above the maximum plasma concentration against HIV isolates with high growth capability without any known drug resistance-related mutation. Our results may contribute to the development of effective strategies to tailor and individualize antiretroviral therapy in patients harboring HIV isolates with high growth capability.

Low-frequency pre-treatment HIV drug resistance: effects on 2-year outcome of first-line efavirenz-based antiretroviral therapy

OBJECTIVES

Assess the impact of pre-treatment high-frequency and low-frequency drug-resistant HIV variants on long-term outcomes of first-line efavirenz-based antiretroviral therapy (ART).

DESIGN

Prospective observational study.

METHODS

Participants' pre-treatment plasma RNA had two sections of HIV pol encoding reverse transcriptase sequenced (Illumina, MiSeq) using unique molecular identifiers to detect wild-type (pre-treatment drug-resistant variants less than 1% of viral quasispecies), low-frequency (1-9%) or high-frequency drug-resistant variants (10-100%). Associations between pre-treatment drug resistance and virologic outcomes over 24 months of efavirenz-based ART were assessed for the number and frequency of mutations by drug class and other resistance parameters.

RESULTS

Virologic failure was detected in 30 of 352 (9%) and pre-treatment drug-resistant variants were detected in the viral quasispecies of 31 of 352 (9%) participants prescribed efavirenz-based ART. Survival analyses revealed statistically significant associations between pre-treatment drug resistance at low (P < 0.0001) and high (P < 0.001) frequencies, at oligonucleotide ligation assay (OLA) (P < 0.00001) and non-OLA (P < 0.01) codons, to a single-antiretroviral class (P < 0.00001), and a shorter time to virologic failure of efavirenz-based ART. Regression analyses detected independent effects across resistance categories, including both low-frequency (P < 0.01) and high-frequency (P < 0.001) drug-resistant variants.

CONCLUSION

We observed that pre-treatment HIV drug resistance detected at low frequencies increased the risk of virologic failure over 24 months of efavirenz-based ART, but that most failures, regardless of drug-resistant variants' frequencies, were detected within a year of ART initiation. These observations suggest that when efavirenz-based ART is prescribed, screening for pre-treatment drug resistance by an assay capable of detecting low-frequency variants, including OLA, may guide clinicians to prescribe more effective ART.

Establishment and application of a method of tagged-amplicon deep sequencing for low-abundance drug resistance in HIV-1

In the latest HIV-1 global drug resistance report released by WHO, countries are advised to strengthen pre-treatment monitoring of drug resistance in AIDS patients. In this study, we established an NGS-based segmented amplification HIV-1 drug resistance mutation detection method. The pol region of HIV-1 was divided into three short fragments for NGS. The entire amplification and sequencing panel were more cost-effective and batched by using the barcode sequence corresponding to the sample. Each parameter was evaluated using samples with known resistance variants frequencies. The nucleotide sequence error rate, amino acid error rate, and noise value of the NGS-based segmented amplification method were both less than 1%. When the threshold was 2%, the consensus sequences of the HIV-1 NL4-3 strain were completely consistent with the Sanger sequences. This method can detect the minimum viral load of the sample at 10² copies/ml, and the input frequency and detection frequency of HIV-1 resistance mutations within the range of 1%–100% had good conformity (R² = 0.9963; R² = 0.9955). This method had no non-specific amplification for Hepatitis B and C. Under the 2% threshold, the incidence of surveillance drug resistance mutations in ART-naive HIV-infected patients was 20.69%, among which NRTIs class resistance mutations were mainly.

Low-frequency HIV-1 drug resistance mutations in antiretroviral naïve individuals in Botswana

BACKGROUND

Individuals living with human immunodeficiency virus (HIV) who experience virological failure (VF) after combination antiretroviral therapy (cART) initiation may have had low-frequency drug resistance mutations (DRMs) at cART initiation. There are no data on low-frequency DRMs among cART-naïve HIV-positive individuals in Botswana.

METHODS

We evaluated the prevalence of low-frequency DRMs among cART-naïve individuals previously sequenced using Sanger sequencing. The generated pol amplicons were sequenced by next-generation sequencing.

RESULTS

We observed low-frequency DRMs (detected at <20% in 33/103 (32%) of the successfully sequenced individuals, of whom four also had mutations detected at >20%. K65R was the most common low-frequency DRM detected in 8 individuals. Eighty-two of the 103 individuals had follow-up viral load data while on cART. Twenty-seven of the 82 individuals harbored low-frequency DRMs. Only 12 of 82 individuals experienced VF. The following low-frequency DRMs were observed in four individuals experiencing VF: K65R, K103N, V108I, and Y188C. No statistically significant difference was observed in the prevalence of low-frequency DRMs between individuals experiencing VF (4/12) and those not experiencing VF (23/70) (P = .97). However, individuals with non-nucleoside reverse transcriptase inhibitors-associated low-frequency DRMs were 2.68 times more likely to experience VF (odds ratio, 2.68; 95% confidential interval, 0.4-13.9) compared with those without (P = .22).

CONCLUSION

Next-generation sequencing was able to detect low-frequency DRMs in this cohort in Botswana, but these DRMs did not contribute significantly to VF.

Probe Capture Enrichment Methods for HIV and HCV Genome Sequencing and Drug Resistance Genotyping

Human immunodeficiency virus (HIV) infections remain a significant public health concern worldwide. Over the years, sophisticated sequencing technologies such as next-generation sequencing (NGS) have emerged and been utilized to monitor the spread of HIV drug resistance (HIVDR), identify HIV drug resistance mutations, and characterize transmission dynamics. Similar applications also apply to the Hepatitis C virus (HCV), another bloodborne viral pathogen with significant intra-host genetic diversity. Several advantages to using NGS over conventional Sanger sequencing include increased data throughput, scalability, cost-effectiveness when batched sample testing is performed, and sensitivity for quantitative detection of minority resistant variants. However, NGS alone may fail to detect genomes from pathogens present in low copy numbers. As with all sequencing platforms, the primary determinant in achieving quality sequencing data is the quality and quantity of the initial template input. Samples containing degraded RNA/DNA and/or low copy number have been a consistent sequencing challenge. To overcome this limitation probe capture enrichment is a method that has recently been employed to target, enrich, and sequence the genome of a pathogen present in low copies, and for compromised specimens that contain poor quality nucleic acids. It involves the hybridization of sequence-specific DNA or RNA probes to a target sequence, which is followed by an enrichment step via PCR to increase the number of copies of the targeted sequences after which the samples are subjected to NGS procedures. This method has been performed on pathogens such as bacteria, fungus, and viruses and allows for the sequencing of complete genomes, with high coverage. Post NGS, data analysis can be performed through various bioinformatics pipelines which can provide information on genetic diversity, genotype, virulence, and drug resistance. This article reviews how probe capture enrichment helps to increase the likelihood of sequencing HIV and HCV samples that contain low viral loads and/or are compromised.

Assessing in vivo mutation frequencies and creating a high-resolution genome-wide map of fitness costs of Hepatitis C virus

Like many viruses, Hepatitis C Virus (HCV) has a high mutation rate, which helps the virus adapt quickly, but mutations come with fitness costs. Fitness costs can be studied by different approaches, such as experimental or frequency-based approaches. The frequency-based approach is particularly useful to estimate in vivo fitness costs, but this approach works best with deep sequencing data from many hosts are. In this study, we applied the frequency-based approach to a large dataset of 195 patients and estimated the fitness costs of mutations at 7957 sites along the HCV genome. We used beta regression and random forest models to better understand how different factors influenced fitness costs. Our results revealed that costs of nonsynonymous mutations were three times higher than those of synonymous mutations, and mutations at nucleotides A or T had higher costs than those at C or G. Genome location had a modest effect, with lower costs for mutations in HVR1 and higher costs for mutations in Core and NS5B. Resistance mutations were, on average, costlier than other mutations. Our results show that in vivo fitness costs of mutations can be site and virus specific, reinforcing the utility of constructing in vivo fitness cost maps of viral genomes.

Exploiting genomics to mitigate the public health impact of antimicrobial resistance

Antimicrobial resistance (AMR) is a major global public health threat, which has been largely driven by the excessive use of antimicrobials. Control measures are urgently needed to slow the trajectory of AMR but are hampered by an incomplete understanding of the interplay between pathogens, AMR encoding genes, and mobile genetic elements at a microbial level. These factors, combined with the human, animal, and environmental interactions that underlie AMR dissemination at a population level, make for a highly complex landscape. Whole-genome sequencing (WGS) and, more recently, metagenomic analyses have greatly enhanced our understanding of these processes, and these approaches are informing mitigation strategies for how we better understand and control AMR. This review explores how WGS techniques have advanced global, national, and local AMR surveillance, and how this improved understanding is being applied to inform solutions, such as novel diagnostic methods that allow antimicrobial use to be optimised and vaccination strategies for better controlling AMR. We highlight some future opportunities for AMR control informed by genomic sequencing, along with the remaining challenges that must be overcome to fully realise the potential of WGS approaches for international AMR control.

Long-acting cabotegravir and rilpivirine for HIV-1 suppression: switch to 2-monthly dosing after 5 years of daily oral therapy

OBJECTIVES

Long-acting formulations of cabotegravir (CAB) and rilpivirine (RPV) have demonstrated efficacy in Phase 3 studies. POLAR (NCT03639311) assessed antiviral activity and safety of CAB+RPV long-acting administered every 2 months (Q2M) in adults living with HIV-1 who previously received daily oral CAB+RPV in LATTE (NCT01641809).

DESIGN

A Phase 2b, multicenter, open-label, rollover study.

METHODS

LATTE participants with plasma HIV-1 RNA less than 50 copies/ml who completed at least 300 weeks on study were eligible. Participants elected to switch to either CAB+RPV long-acting Q2M or daily oral dolutegravir/RPV for maintenance of virologic suppression. The primary endpoint was the proportion of participants with HIV-1 RNA greater than or equal to 50 copies/ml at Month 12 (M12) per the Food and Drug Administration Snapshot algorithm. The incidence of confirmed virologic failure (CVF, two consecutive HIV-1 RNA measurements greater than or equal to 200 copies/ml), as well as safety, laboratory, and patient-reported outcomes (HIV Treatment Satisfaction and preference questionnaires) were also assessed.

RESULTS

Of 97 participants enrolled, 90 chose to receive CAB+RPV long-acting and seven chose dolutegravir/RPV. At M12, no participant had HIV-1 RNA greater than or equal to 50 copies/ml or met the CVF criterion in either treatment group. No new safety signals were identified. Total treatment satisfaction was high at Baseline and remained stable through M12 across both treatment groups. Overall, 88% (n = 77/88) of long-acting arm participants preferred CAB+RPV long-acting to oral CAB+RPV.

CONCLUSION

CAB+RPV long-acting maintained virologic suppression in participants who had previously received daily oral CAB+RPV for at least 5 years in LATTE, with a favorable safety profile. Most participants preferred CAB+RPV long-acting to their prior oral CAB+RPV regimen at M12.

High Level of Pre-Treatment HIV-1 Drug Resistance and Its Association with HLA Class I-Mediated Restriction in the Pumwani Sex Worker Cohort

Background: We analyzed the prevalence of pre-antiretroviral therapy (ART) drug resistance mutations (DRMs) in a Kenyan population. We also examined whether host HLA class I genes influence the development of pre-ART DRMs. Methods: The HIV-1 proviral DNAs were amplified from blood samples of 266 ART-naïve women from the Pumwani Sex Worker cohort of Nairobi, Kenya using a nested PCR method. The amplified HIV genomes were sequenced using next-generation sequencing technology. The prevalence of pre-ART DRMs was investigated. Correlation studies were performed between HLA class I alleles and HIV-1 DRMs. Results: Ninety-eight percent of participants had at least one DRM, while 38% had at least one WHO surveillance DRM. M184I was the most prevalent clinically important variant, seen in 37% of participants. The DRMs conferring resistance to one or more integrase strand transfer inhibitors were also found in up to 10% of participants. Eighteen potentially relevant (p < 0.05) positive correlations were found between HLA class 1 alleles and HIV drug-resistant variants. Conclusions: High levels of HIV drug resistance were found in all classes of antiretroviral drugs included in the current first-line ART regimens in Africa. The development of DRMs may be influenced by host HLA class I-restricted immunity.

Transmitted Drug Resistance in Antiretroviral Therapy-Naive Persons With Acute/Early/Primary HIV Infection: A Systematic Review and Meta-Analysis

Background: The widespread use of antiretroviral therapy (ART) has raised concerns about the emergence of HIV transmitted drug resistance (TDR). Acute HIV infection (AHI) was the most appropriate time to detect the spread of TDR. In this meta-analysis, our purpose was to evaluate the level of TDR in ART-naive patients with primary HIV infection (PHI)/AHI/early HIV infection (EHI) and to describe the critical drug-resistant mutations.

Methods: We systematically searched the literature between January 1, 2008, and April 30, 2021, in PubMed, Web of Science, Embase, and the Cochrane Library. To evaluate the overall prevalence of TDR, we extracted raw data and analyzed prevalence estimates using Stata SE.

Results: The data of this meta-analysis come from 12 observational studies, covering 3,558 ART-naive individuals with PHI, AHI, or EHI. The overall prevalence of HIV-TDR is 9.3% (95% CI: 6.8%–11.8%, I² = 81.1%, in 11 studies). The prevalence of resistance by drug class is the highest for the nonnucleoside reverse transcriptase inhibitors (NNRTIs) at 5.7% (95% CI: 2.9%–8.5%, I² = 96.6%, in 11 studies), followed by nucleoside reverse transcriptase inhibitors (NRTIs) at 3.4% (95% CI: 1.8%–5.0%, I² = 86.3%, in 10 studies) and protease inhibitors (PIs) at 3.3% (95% CI: 2.7%–3.9%, I² = 15.6%, in 10 studies). The prevalence of TDR to integrase inhibitors (INIs) is 0.3% (95% CI: 0.1%–0.7%, I² = 95.9%, in three studies), which is the lowest among all antiretroviral drugs.

Conclusion: The overall prevalence of TDR is at a moderate level among AHI patients who have never received ART. This emphasizes the importance of baseline drug resistance testing for public health surveillance and guiding the choice of ART. In addition, the prevalence of TDR to NNRTIs is the highest, while the TDR to INIs is the lowest. This may guide the selection of clinical antiretroviral drugs.

Diversity of HIV-1 subtypes and transmitted drug-resistance mutations among minority HIV-1 variants in a Turkish cohort

BACKGROUND

The World Health Organization (WHO) recommends the surveillance of transmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability of HIV treatment programs.

OBJECTIVE

Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypes using and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in a cohort of 44 antiretroviral treatment-naïve patients.

METHODS

All samples that were referred to the microbiology laboratory for HIV drug resistance analysis between December 2016 and February 2018 were included in the study. After exclusions, 44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencing for reverse transcriptase and protease regions was performed using both DeepChek ABL single round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1 subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software, and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1 subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los Alamos IQ-Tree software.

RESULTS

NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1% of the patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8% of the patients, and protease inhibitor (PI)-TDRMs in 18.2% of the patients at a detection threshold of ≥1%. Using SBS, 2.3% and 6.8% of the patients were found to have NRTI- and NNRTI-TDRMs, respectively, but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I related to NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI sites were identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0% - 4.7%) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows; 61.4% subtype B, 18.2% subtype B/CRF02_AG recombinant, 13.6% subtype A, 4.5% CRF43_02G, and 2.3% CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype B isolates.

CONCLUSION

The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalence of CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventional sequencing. TDRM prevalence among minority variants appears to be decreasing over time at our center.

CODEHOP-Mediated PCR Improves HIV-1 Genotyping and Detection of Variants by MinION Sequencing

HIV-1 is genetically heterogeneous, having different subtypes and circulating recombinant forms (CRFs). HIV-1 genotyping is used to determine drug resistance profiles and is based on the use of a mixture of consensus and degenerate primers targeting the pol gene. However, the use of this type of primers is associated with either PCR bias or PCR failure. Consensus-degenerate hybrid oligonucleotide primers (CODEHOPs) can detect and identify unknown and distantly related gene sequences by PCR. CODEHOPs designed using different HIV-1 subtypes and CRFs were evaluated for HIV-1 genotyping by Sanger and MinION sequencing. A total of 321 plasma samples were used for the validation of CODEHOP-mediated HIV-1 genotyping. CODEHOP-mediated PCR showed 100% sensitivity and specificity, with limits of detection and genotyping below 200 copies/ml. The head-to-head evaluation of CODEHOP-mediated PCR and standard PCR showed 97 to 98% and 82 to 84% PCR success rates, respectively. There was 100% agreement between the CODEHOP and the reference method in the drug resistance profiles determined by Sanger-based sequencing. Using MinION sequencing, the CODEHOP-mediated PCR scheme resulted in better depth of genome coverage and detection of more drug resistance variants in the protease and reverse transcriptase genes than the standard amplification scheme. The overall prevalences of drug resistance mutations were 17.1% in treatment-experienced patients and 1.2% in treatment-naive patients. They were mainly associated with resistance to reverse transcriptase inhibitors and were linked to virological failure and the patient’s treatment history. Findings from this study suggest that the performance of HIV-1 genotyping is improved by using CODEHOP-mediated PCR.

IMPORTANCE HIV-1 drug resistance is the main cause of treatment failure. Regular surveillance of resistance-associated mutations in HIV-1 genomes is essential for the optimal management of HIV-1 infections. Due to HIV-1’s genetic diversity, different HIV-1 genotypes are circulating worldwide. Standard primers used in the amplification of HIV-1 RNA have not been designed to cover all HIV-1 genotypes and are the main cause of amplification and drug resistance test failure. In this study, new sets of PCR primers targeting the protease, reverse transcriptase, and integrase genes were designed using the CODEHOP approach. They were compared to primers recommended in part by WHO for drug resistance testing using in-house PCR. Unsuccessful HIV-1 RNA amplification was less likely to occur with CODEHOP primers, leading to fewer test failures and lower cost. Furthermore, CODEHOP primers were more effective than standard primers for the detection of minority resistant variants by MinION sequencing.

Kinetics of archived M184V mutation in treatment-experienced virally suppressed HIV-infected patients

BACKGROUND

We aimed to assess the kinetics of drug-resistant viral variants (DRVs) harboring the M184V mutation in the proviral DNA of long-term virally suppressed patients, and factors associated with DRV persistence.

METHODS

HIV-DNA from blood cells stored in 2019 and 2016 was sequenced using both Sanger and ultradeep sequencing (SS and UDS, with a detection threshold of 1%) in ART-treated patients with HIV-RNA <50 copies/mL for at least 5 years, with past M184V mutation documented in HIV-RNA.

RESULTS

Among the 79 tested patients, by combining SS and UDS, the M184V was found to be absent in 26/79 (33%) patients (M184V- patients), and persisted in 53/79 (67%) (M184V+ patients). The M184V+ patients had a longer history of ART, a lower CD4 nadir and higher pretherapeutic HIV-RNA. Among the 37 patients with viral sequences assessed by UDS, the proportion of M184V+ DRVs significantly decreased between 2016 and 2019 (40% versus 14%, p=0.005). The persistence of M184V was associated with the duration and level of HIV-RNA replication under 3TC/FTC (p=0.0009 and p=0.009, respectively).

CONCLUSION

While it decreased over time in HIV-DNA, the M184V mutation was more frequently persistent in the HIV-DNA of more experienced patients with longer past replication under 3TC/FTC.

Use of next generation sequencing technologies for the diagnosis and epidemiology of infectious diseases

For the first time, next generation sequencing technologies provide access to genomic information at a price and scale that allow their implementation in routine clinical practice and epidemiology. While there are still many obstacles to their implementation, there are also multiple examples of their major advantages compared with previous methods. Their main advantage is that a single determination allows epidemiological information on the causative microorganism to be obtained simultaneously, as well as its resistance profile, although these advantages vary according to the pathogen under study. This review discusses several examples of the clinical and epidemiological use of next generation sequencing applied to complete genomes and microbiomes and reflects on its future in clinical practice.

HAPHPIPE: Haplotype Reconstruction and Phylodynamics for Deep Sequencing of Intrahost Viral Populations

Deep sequencing of viral populations using next-generation sequencing (NGS) offers opportunities to understand and investigate evolution, transmission dynamics, and population genetics. Currently, the standard practice for processing NGS data to study viral populations is to summarize all the observed sequences from a sample as a single consensus sequence, thus discarding valuable information about the intrahost viral molecular epidemiology. Furthermore, existing analytical pipelines may only analyze genomic regions involved in drug resistance, thus are not suited for full viral genome analysis. Here, we present HAPHPIPE, a HAplotype and PHylodynamics PIPEline for genome-wide assembly of viral consensus sequences and haplotypes. The HAPHPIPE protocol includes modules for quality trimming, error correction, de novo assembly, alignment, and haplotype reconstruction. The resulting consensus sequences, haplotypes, and alignments can be further analyzed using a variety of phylogenetic and population genetic software. HAPHPIPE is designed to provide users with a single pipeline to rapidly analyze sequences from viral populations generated from NGS platforms and provide quality output properly formatted for downstream evolutionary analyses.

Impact of pre-existing drug resistance on risk of virological failure in South Africa

OBJECTIVES

There is conflicting evidence on the impact of pre-existing HIV drug resistance mutations (DRMs) in patients infected with non-B subtype virus.

METHODS

We performed a case-cohort substudy of the AIDS Drug Resistance Surveillance Study, which enrolled South African patients initiating first-line efavirenz/emtricitabine/tenofovir. Pre-ART DRMs were detected by Illumina sequencing of HIV pol and DRMs present at <20% of the viral population were labelled as minority variants (MVs). Weighted Cox proportional hazards models estimated the association between pre-ART DRMs and risk of virological failure (VF), defined as confirmed HIV-1 RNA ≥1000 copies/mL after ≥5 months of ART.

RESULTS

The evaluable population included 178 participants from a randomly selected subcohort (16 with VF, 162 without VF) and 83 additional participants with VF. In the subcohort, 16% of participants harboured ≥1 majority DRM. The presence of any majority DRM was associated with a 3-fold greater risk of VF (P = 0.002), which increased to 9.2-fold (P < 0.001) in those with <2 active drugs. Thirteen percent of participants harboured MV DRMs in the absence of majority DRMs. Presence of MVs alone had no significant impact on the risk of VF. Inclusion of pre-ART MVs with majority DRMs improved the sensitivity but reduced the specificity of predicting VF.

CONCLUSIONS

In a South African cohort, the presence of majority DRMs increased the risk of VF, especially for participants receiving <2 active drugs. The detection of drug-resistant MVs alone did not predict an increased risk of VF, but their inclusion with majority DRMs affected the sensitivity/specificity of predicting VF.

Surveillance of HIV-1 transmitted integrase strand transfer inhibitor resistance in the UK

Background

HIV treatment guidelines have traditionally recommended that all HIV-positive individuals are tested for evidence of drug resistance prior to starting ART. Testing for resistance to reverse transcriptase inhibitors and PIs is well established in routine care. However, testing for integrase strand transfer inhibitor (InSTI) resistance is less consistent.

Objectives

To inform treatment guidelines by determining the prevalence of InSTI resistance in a national cohort of recently infected individuals.

Patients and methods

Recent (within 4 months) HIV-1 infections were identified using a Recent Infection Testing Algorithm of new HIV-1 diagnoses in the UK. Resistance-associated mutations (RAMs) in integrase, protease and reverse transcriptase were detected by ultradeep sequencing, which allows for the sensitive estimation of the frequency of each resistant variant in a sample.

Results

The analysis included 655 randomly selected individuals (median age = 33 years, 95% male, 83% MSM, 78% white) sampled in the period 2014 to 2016 and determined to have a recent infection. These comprised 320, 138 and 197 samples from 2014, 2015 and 2016, respectively. None of the samples had major InSTI RAMs occurring at high variant frequency (≥20%). A subset (25/640, 3.9%) had major InSTI RAMs occurring only as low-frequency variants (2%–20%). In contrast, 47/588 (8.0%) had major reverse transcriptase inhibitor and PI RAMs at high frequency.

Conclusions

Between 2014 and 2016, major InSTI RAMs were uncommon in adults with recent HIV-1 infection, only occurring as low-frequency variants of doubtful clinical significance. Continued surveillance of newly diagnosed patients for evidence of transmitted InSTI resistance is recommended to inform clinical practice.

Investigation of drug resistance against protease, reverse transcriptase, and integrase inhibitors by next-generation sequencing in HIV-positive patients

Our aim was to investigate the mutations in protease (PR), reverse transcriptase (RT), and integrase (IN) gene regions in human immunodeficiency virus (HIV) using a single amplicon via next-generation sequencing (NGS). The study included plasma samples from 49 HIV-1-positive patients, which were referred for HIV-1 drug resistance testing during 2017. A nested polymerase chain reaction (PCR) was performed after the RNA extraction and one-step reverse transcription stages. The sequencing of the HIV genome in the PR, RT, and IN gene regions was carried out using MiSeq NGS technology. Sanger sequencing (SS) was used to analyze resistance mutations in the PR and RT gene regions using a ViroSeq HIV-1 Genotyping System. PCR products were analyzed with an ABI3500 GeneticAnalyzer (Applied Biosystems). Resistance mutations detected with NGS at frequencies above 20% were identical to the SS results. Resistance to at least one antiretroviral (ARV) drug was 22.4% (11 of 49) with NGS and 10.2% (5 of 49) with SS. At least one low-frequency resistance mutation was detected in 18.3% (9 of 49) of the samples. Low-frequency resistance mutations resulted in virological failure in only one patient. The cost of the analyses was reduced by sample pooling and multiplex analysis using the MiSeq system. This is the first study in Turkey to use NGS technologies for the detection of resistance mutations in all three gene (PR, RT, IN) regions using a single amplicon. Our findings suggest that NGS is more sensitive and cost-effective than the SS method.

Drug resistance mutations in HIV provirus are associated with defective proviral genomes with hypermutation

BACKGROUND

HIV proviral sequencing overcomes the limit of plasma viral load requirement by detecting all the 'archived mutations', but the clinical relevance remains to be evaluated.

METHODS

We included 25 participants with available proviral sequences (both intact and defective sequences available) and utilized the genotypic sensitivity score (GSS) to evaluate the level of resistance in their provirus and plasma virus. Defective sequences were further categorized as sequences with and without hypermutations. Personalized GSS score and total GSS score were calculated to evaluate the level of resistance to a whole panel of antiretroviral therapies and to certain antiretroviral therapy that a participant was using. The rate of sequences with drug resistance mutations (DRMs) within each sequence compartment (intact, defective and plasma viral sequences) was calculated for each participant.

RESULTS

Defective proviral sequences harbored more DRMs than other sequence compartments, with a median DRM rate of 0.25 compared with intact sequences (0.0, P = 0.014) and plasma sequences (0.095, P = 0.30). Defective sequences with hypermutations were the major source of DRMs, with a median DRM rate of 1.0 compared with defective sequences without hypermutations (0.042, P < 0.001). Certain Apolipoprotein B Editing Complex 3-related DRMs including reverse transcriptase gene mutations M184I, E138K, M230I, G190E and protease gene mutations M46I, D30N were enriched in hypermutated sequences but not in intact sequences or plasma sequences. All the hypermutated sequences had premature stop codons due to Apolipoprotein B Editing Complex 3.

CONCLUSION

Proviral sequencing may overestimate DRMs as a result of hypermutations. Removing hypermutated sequences is essential in the interpretation of proviral drug resistance testing.

Patient-Reported Outcomes Through 1 Year of an HIV-1 Clinical Trial Evaluating Long-Acting Cabotegravir and Rilpivirine Administered Every 4 or 8 Weeks (ATLAS-2M)

BACKGROUND

Advances in HIV-1 therapeutics have led to the development of a range of daily oral treatment regimens, which share similar high efficacy rates. Consequently, more emphasis is being placed upon the individual's experience of treatment and impact on quality of life. The first long-acting injectable antiretroviral therapy for HIV-1 (long-acting cabotegravir + rilpivirine [CAB + RPV LA]) may address challenges associated with oral treatment for HIV-1, such as stigma, pill burden/fatigue, drug-food interactions, and adherence. Patient-reported outcomes (PROs) collected in an HIV-1 clinical trial (ATLAS-2M; NCT03299049) comparing participants' experience with two dosing regimens (every 4 weeks [Q4W] vs. every 8 weeks [Q8W]) of CAB + RPV LA are presented herein.

METHODS

PRO endpoints evaluated through 48 weeks of therapy included treatment satisfaction (HIV Treatment Satisfaction Questionnaire [HIVTSQ]), treatment acceptance ("General Acceptance" domain of the Chronic Treatment Acceptance [ACCEPT^®] questionnaire), acceptability of injections (Perception of Injection [PIN] questionnaire), treatment preference (questionnaire), and reasons for switching to/continuing long-acting therapy (exploratory endpoint; questionnaire). Participants were randomized 1:1 to receive CAB + RPV LA Q8W or Q4W. Results were stratified by prior CAB + RPV exposure in either preplanned or post hoc analyses.

RESULTS

Overall, 1045 participants were randomized to the Q8W (n = 522) and Q4W (n = 523) regimens; 37% (n = 391/1045) had previously received CAB + RPV in ATLAS. For participants without prior CAB + RPV exposure, large increases from baseline were reported in treatment satisfaction in both long-acting arms (HIVTSQ status version), with Q8W dosing statistically significantly favored at Weeks 24 (p = 0.036) and 48 (p = 0.004). Additionally, improvements from baseline were also observed in the "General Acceptance" domain of the ACCEPT questionnaire in both long-acting arms for participants without prior CAB + RPV exposure; however, no statistically significant difference was observed between arms at either timepoint (Week 24, p = 0.379; Week 48, p = 0.525). Significant improvements (p < 0.001) in the "Acceptance of Injection Site Reactions" domain of the PIN questionnaire were observed from Week 8 to Weeks 24 and 48 in both arms for participants without prior CAB + RPV exposure. Participants with prior CAB + RPV exposure reported high treatment satisfaction (mean [HIVTSQ status version]: Q8W 62.2/66.0; Q4W 62.0/66.0), treatment acceptance (mean: Q8W 89.3/100; Q4W 91.2/100), and acceptance of injection site reactions (mean [5 = not at all acceptable; 1 = totally acceptable]: Q8W 1.72; Q4W 1.59) at baseline/Week 8 that were maintained over time. Participants without prior CAB + RPV exposure who received Q8W dosing preferred this regimen over oral CAB + RPV (98%, n = 300/306). Among those with prior Q4W exposure, 94% (n = 179/191) preferred Q8W dosing versus Q4W dosing (3%, n = 6/191) or oral CAB + RPV (2%, n = 4/191).

CONCLUSIONS

Both long-acting regimens provided high treatment satisfaction and acceptance, irrespective of prior CAB + RPV exposure, with most participants preferring Q8W dosing over both the Q4W regimen and their previous daily oral regimen. The PRO data collected at Week 48 support the therapeutic potential of CAB + RPV LA.

FUNDING

ViiV Healthcare and Janssen.

TRIAL REGISTRATION

ATLAS-2M: ClinicalTrials.gov NCT03299049, registered October 2, 2017.

Transmitted HIV-1 drug resistance in a large international cohort using next-generation sequencing: results from the Strategic Timing of Antiretroviral Treatment (START) study

OBJECTIVES

The aim of this analysis was to characterize transmitted drug resistance (TDR) in Strategic Timing of Antiretroviral Treatment (START) study participants by next-generation sequencing (NGS), a sensitive assay capable of detecting low-frequency variants.

METHODS

Stored plasma from participants with entry HIV RNA > 1000 copies/mL were analysed by NGS (Illumina MiSeq). TDR was based on the WHO 2009 surveillance definition with the addition of reverse transcriptase (RT) mutations T215N and E138K, and integrase strand transfer inhibitor (INSTI) surveillance mutations (Stanford HIVdb). Drug resistance mutations (DRMs) detected at three thresholds are reported: > 2%, 5% and 20% of the viral population.

RESULTS

Between 2009 and 2013, START enrolled 4684 antiretroviral therapy (ART)-naïve individuals in 35 countries. Baseline NGS data at study entry were available for 2902 participants. Overall prevalence rates of TDR using a detection threshold of 2%/5%/20% were 9.2%/5.6%/3.2% for nucleoside reverse transcriptase inhibitors (NRTIs), 9.2%/6.6%/4.9% for non-NRTIs, 11.4%/5.5%/2.4% for protease inhibitors (PIs) and 3.5%/1.6%/0.1% for INSTI DRMs and varied by geographic region. Using the 2% detection threshold, individual DRMs with the highest prevalence were: PI M46IL (5.5%), RT K103NS (3.5%), RT G190ASE (3.1%), T215ISCDVEN (2.5%), RT M41L (2.2%), RT K219QENR (1.7%) and PI D30N (1.6%). INSTI DRMs were detected almost exclusively below the 20% detection threshold, most commonly Y143H (0.4%), Q148R (0.4%) and T66I (0.4%).

CONCLUSIONS

Use of NGS in this study population resulted in the detection of a large proportion of low-level variants which would not have been detected by traditional Sanger sequencing. Global surveillance studies utilizing NGS should provide a more comprehensive assessment of TDR prevalence in different regions of the world.

An observational study of high- and low-abundance anti-retroviral resistance mutations among treatment-naïve people living with HIV in New Zealand between 2012 and 2017

HIV resistance genotyping detects drug resistance mutations (DRMs) in ≥20% of circulating virus within an infected individual (high-abundance DRMs). Deep sequencing also detects DRMs in smaller viral subpopulations (low-abundance DRMs), although these are of uncertain importance. In this retrospective analysis of 292 treatment-naïve patients, high-abundance DRMs were present in 30/292 (10%) patients, but only one (0.3%) had resistance to first-line anti-retrovirals. Low-abundance DRMs were present in 36/247 (15%) patients, but none who received anti-retrovirals for which these were present had virologic failure. These findings demonstrate that starting first-line therapy in treatment-naïve patients need not be delayed while awaiting resistance testing.

Association of CYP2B6 Genetic Variation with Efavirenz and Nevirapine Drug Resistance in HIV-1 Patients from Botswana

Purpose

CYP2B6 liver enzyme metabolizes the two non-nucleoside reverse transcriptase inhibitors Efavirenz (EFV) and Nevirapine (NVP) used in the antiretroviral therapy (ART) regimens for HIV-infected individuals. Polymorphisms of the CYP2B6 gene influence drug levels in plasma and possibly virological outcomes. The aim of this study was to explore the potential impact of CYP2B6 genotype and haplotype variation on the risk of developing EFV/NVP drug resistance mutations (DRMs) in HIV-1 patients receiving EFV-/NVP-containing regimens in Botswana.

Patients and Methods

Participants were a sub-sample of a larger study (Tshepo study) conducted in Gaborone, Botswana, among HIV-infected individuals taking EFV/NVP containing ART. Study samples were retrieved and assigned to cases (with DRMs) and controls (without DRMs). Four single-nucleotide polymorphisms (SNPs) in the CYP2B6 gene (−82T>C; 516G>T; 785A>G; 983T>C) were genotyped, the haplotypes reconstructed, and the metabolic score assigned. The possible association between drug resistance and several independent factors (baseline characteristics and CYP2B6 genotypes) was assessed by Binary Logistic Regression (BLR) analysis. EFV/NVP resistance status and CYP2B6 haplotypes were also analyzed using Z-test, chi-square and Fisher’s exact test statistics.

Results

Two hundred and twenty-seven samples were analysed (40 with DRMs, 187 without DRMs). BLR analysis showed an association between EFV/NVP resistance and CYP2B6 516G allele (OR: 2.26; 95% CI: 1.27–4.01; P=0.005). Moreover, haplotype analysis revealed that the proportion of EFV/NVP-resistant infections was higher among CYP2B6 fast than extensive/slow metabolizers (30.8% vs 16.8%; P=0.035), with the 516G allele more represented in the haplotypes of fast than extensive/slow metabolizers (100.0% vs 53.8%; P<0.001).

Conclusion

We demonstrated that the CYP2B6 516G allele, and even more when combined in fast metabolic haplotypes, is associated with the presence of EFV/NVP resistance, strengthening the need to assess the CYP2B6 genetic profiles in HIV-infected patients in order to improve the virologic outcomes of NNRTI containing ART.

Increased acquired protease inhibitor drug resistance mutations in minor HIV-1 quasispecies from infected patients suspected of failing on national second-line therapy in South Africa

BACKGROUND

HIV-1C has been shown to have a greater risk of virological failure and reduced susceptibility towards boosted protease inhibitors (bPIs), a component of second-line combination antiretroviral therapy (cART) in South Africa. This study entailed an evaluation of HIV-1 drug resistance-associated mutations (RAMs) among minor viral populations through high-throughput sequencing genotypic resistance testing (HTS-GRT) in patients on the South African national second-line cART regimen receiving bPIs.

METHODS

During 2017 and 2018, 67 patient samples were sequenced using high-throughput sequencing (HTS), of which 56 samples were included in the final analysis because the patient's treatment regimen was available at the time of sampling. All patients were receiving bPIs as part of their cART. Viral RNA was extracted, and complete pol genes were amplified and sequenced using Illumina HiSeq2500, followed by bioinformatics analysis to quantify the RAMs according to the Stanford HIV Drug Resistance Database.

RESULTS

Statistically significantly higher PI RAMs were observed in minor viral quasispecies (25%; 14/56) compared to non-nucleoside reverse transcriptase inhibitors (9%; 5/56; p = 0.042) and integrase inhibitor RAM (4%; 2/56; p = 0.002). The majority of the drug resistance mutations in the minor viral quasispecies were observed in the V82A mutation (n = 13) in protease and K65R (n = 5), K103N (n = 7) and M184V (n = 5) in reverse transcriptase.

CONCLUSIONS

HTS-GRT improved the identification of PI and reverse transcriptase inhibitor (RTI) RAMs in second-line cART patients from South Africa compared to the conventional GRT with ≥20% used in Sanger-based sequencing. Several RTI RAMs, such as K65R, M184V or K103N and PI RAM V82A, were identified in < 20% of the population. Deep sequencing could be of greater value in detecting acquired resistance mutations early.

Low-Abundance Drug-Resistant HIV-1 Variants in Antiretroviral Drug-Naive Individuals: A Systematic Review of Detection Methods, Prevalence, and Clinical Impact

BACKGROUND

The presence of high-abundance drug-resistant HIV-1 jeopardizes success of antiretroviral therapy (ART). Despite numerous investigations, the clinical impact of low-abundance drug-resistant HIV-1 variants (LA-DRVs) at levels <15%-25% of the virus population in antiretroviral (ARV) drug-naive individuals remains controversial.

METHODS

We systematically reviewed 103 studies assessing prevalence, detection methods, technical and clinical detection cutoffs, and clinical significance of LA-DRVs in antiretroviral drug-naive adults.

RESULTS

In total, 14 919 ARV drug-naive individuals were included. Prevalence of LA-DRVs (ie, proportion of individuals harboring LA-DRVs) was 0%-100%. Technical detection cutoffs showed a 4 log range (0.001%-10%); 42/103 (40.8%) studies investigating the impact of LA-DRVs on ART; 25 studies included only individuals on first-line nonnucleoside reverse transcriptase inhibitor-based ART regimens. Eleven of those 25 studies (44.0%) reported a significantly association between preexisting LA-DRVs and risk of virological failure whereas 14/25 (56.0%) did not.

CONCLUSIONS

Comparability of the 103 studies is hampered by high heterogeneity of the studies' designs and use of different methods to detect LA-DRVs. Thus, evaluating clinical impact of LA-DRVs on first-line ART remains challenging. We, the WHO HIVResNet working group, defined central areas of future investigations to guide further efforts to implement ultrasensitive resistance testing in routine settings.

Quality of systematic reviews in HIV: The case of clinical outcomes associated with patient medication adherence

AIM

Use of systematic reviews (SRs) as first-level evidence for guideline recommendations hinges on review quality. In particular, US guidelines for adherence-related recommendations in the treatment of human immunodeficiency virus (HIV) are not based on available SRs of adherence-outcome relationships; it is unclear why. No published studies report on the quality of SRs on HIV adherence and outcomes, which may be driving the lack of use. We describe the quality of this body of literature.

METHODS

Literature searches were conducted in Ovid MEDLINE, EMBASE, CINAHL, PubMed Central, the Cochrane Library, Science Citation Index, Web of Science, ScIELO Citation Index, and Ovid Emcare. Screening and quality assessments were performed in duplicate using AMSTAR 2. Funding sources and impact factors of publishing journals were also extracted, and correlations between quality rankings and numbers of critical weaknesses versus impact factors were assessed using Spearman's rank correlation coefficient.

RESULTS

Nine SRs of 1141 records met eligibility criteria. Overall confidence in the results was critically low for most (78%) SRs. Underperformance was found across all AMSTAR 2 domains. Impact factor (a surrogate or journal reputation) did not correlate with quality.

CONCLUSIONS

SRs do not necessarily comprise top-level evidence despite the availability of quality appraisal tools and reporting guidance, which could explain the lack of SR evidence in US HIV medication adherence-related guideline recommendations. All parties to evidence synthesis publication should require quality assessment of studies.

Prevalence of HIV-1 Integrase Strand Transfer Inhibitor Resistance in Treatment-Naïve Voluntary Counselling and Testing Clients by Population Sequencing and Illumina Next-Generation Sequencing in Taiwan

Purpose

Integrase strand transfer inhibitors (INSTIs) are used as first-line therapy for HIV-1-infected patients. Next-generation sequencing (NGS) can detect low-frequency mutants; however, the clinical value of NGS to detect resistance variants is unknown. This study aimed to evaluate the prevalence of INSTI resistance in southern Taiwan and determine the clinical implications of using NGS to detect integrase region low-level resistant variants.

Patients and Methods

This retrospective cohort study included antiretroviral therapy-naïve HIV-1-infected individuals at Kaohsiung Veterans General Hospital, Taiwan, from 2013 to 2017. Drug-resistance mutations were determined, and an in-house polymerase chain reaction was used for genotyping INSTI resistance. NGS was used to assess INSTI resistance (≧1%), and the results were compared with those from population sequencing. Drug resistance-associated mutations were defined according to the 2019 IAS-USA HIV drug resistance-associated mutations list, and accessory mutations by a Stanford HIVdb score ≥10 to at least one INSTI.

Results

A total of 224 patients were included. Subtype B HIV-1 strains were found in 96% of the individuals and subtype CRF01_AE in 4%. The prevalence rates for nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors and INSTI resistance were 4%, 5.8%, 0.4% and 0.9%, respectively. The most common INSTI resistance-associated mutations were G163K (0.4%) and E138A (0.4%). Of the 38 patients diagnosed in 2017 who had both NGS and population sequencing data, none had INSTI resistance-associated mutations by population sequencing; however, NGS detected four more INSTI resistance-associated mutations with low frequencies (G163R 3.25%, S153F 3.21%, S153Y 1.36% and Y143H 2.06%). Two patients with S153F and S153Y low frequencies mutations started INSTI-based highly active antiretroviral therapy, and none had virological failure by week 48.

Conclusion

Our findings showed a low rate of HIV drug resistance to INSTIs (0.9%) in treatment-naïve patients. NGS detected more INSTI resistance-associated mutations at a low frequency. Low-level drug resistance-associated mutations to INSTIs identified by NGS did not have an impact on the treatment response to INSTI-based first-line therapy.

Antiretroviral drug use and HIV drug resistance in female sex workers in Tanzania and the Dominican Republic

Objective

Female sex workers (FSW) have increased risk of HIV infection. Antiretroviral treatment (ART) can improve HIV outcomes and prevent HIV transmission. We analyzed antiretroviral (ARV) drug use and HIV drug resistance among HIV-positive FSW in the Dominican Republic and Tanzania.

Methods

Plasma samples collected at study entry with viral loads >1,000 copies/mL were tested for ARV drugs and HIV drug resistance. ARV drug testing was performed using a qualitative assay that detects 22 ARV drugs in five classes. HIV genotyping was performed using the ViroSeq HIV-1 Genotyping System. Phylogenetic analyses were performed to determine HIV subtype and assess transmission clusters.

Results

Among 410 FSW, 144 (35.1%) had viral loads >1,000 copies/mL (DR: n = 50; Tanzania: n = 94). ARV drugs were detected in 36 (25.0%) of 144 samples. HIV genotyping results were obtained for 138 (95.8%) cases. No transmission clusters were observed in either country. HIV drug resistance was detected in 54 (39.1%) of 138 samples (31/35 [88.6%] with drugs detected; 23/103 [22.3%] without drugs detected); 29/138 (21.0%) had multi-class resistance (MCR). None with MCR had integrase strand transfer inhibitor resistance. In eight cases, one or more ARV drug was detected without corresponding resistance mutations; those women were at risk of acquiring additional drug resistance. Using multivariate logistic regression, resistance was associated with ARV drug detection (p<0.001), self-reported ART (full adherence [p = 0.034]; partial adherence [p<0.001]), and duration of HIV infection (p = 0.013).

Conclusions

In this cohort, many women were on ART, but were not virally suppressed. High levels of HIV drug resistance, including MCR, were observed. Resistance was associated with detection of ARV drugs, self-report of ART with full or partial adherence, and duration of HIV infection. These findings highlight the need for better HIV care among FSW to improve their health, reduce HIV drug resistance, and decrease risk of transmission to others.

In vivo drug resistance mutation dynamics from the early to chronic stage of infection in antiretroviral-therapy-naïve HIV-infected men who have sex with men

Human immunodeficiency virus type 1 (HIV) primary drug resistance mutations (DRMs) influence the long-term therapeutic effects of antiretroviral treatment (ART). Drug-resistance genotyping based on polymerase gene sequences obtained by next-generation sequencing (NGS) was performed using samples from 10 ART-naïve HIV-infected men who have sex with men (MSM; P1-P10) from the acute/early to chronic stage of infection. Three of the 10 subjects exhibited the presence of major (abundance, ≥ 20%) viral populations carrying DRM at early/acute stage that later, at the chronic stage, dropped drastically (V106M) or remained highly abundant (E138A). Four individuals exhibited additional DRMs (M46I/L; I47A; I54M, L100V) as HIV minority populations (abundance, 2-20%) that emerged during the chronic stage but ephemerally.

Determining the Origins of Human Immunodeficiency Virus Type 1 Drug-resistant Minority Variants in People Who Are Recently Infected Using Phylogenetic Reconstruction

BACKGROUND

Drug-resistant minority variants (DRMinVs) detected in patients who recently acquired human immunodeficiency virus type 1 (HIV-1) can be transmitted, generated de novo through virus replication, or technical errors. The first form is likely to persist and result in treatment failure, while the latter two could be stochastic and transient.

METHODS

Ultradeep sequencing of plasma samples from 835 individuals with recent HIV-1 infection in the United Kingdom was performed to detect DRMinVs at a mutation frequency between 2% and 20%. Sequence alignments including >110 000 HIV-1 partial pol consensus sequences from the UK HIV Drug Resistance Database (UK-HDRD), linked to epidemiological and clinical data from the HIV and AIDS Reporting System, were used for transmission cluster analysis. Transmission clusters were identified using Cluster Picker with a clade support of >90% and maximum genetic distances of 4.5% or 1.5%, the latter to limit detection to likely direct transmission events.

RESULTS

Drug-resistant majority variants (DRMajVs) were detected in 66 (7.9%) and DRMinVs in 84 (10.1%) of the recently infected individuals. High levels of clustering to sequences in UK-HDRD were observed for both DRMajV (n = 48; 72.7%) and DRMinV (n = 63; 75.0%) sequences. Of these, 43 (65.2%) with DRMajVs were in a transmission cluster with sequences that harbored the same DR mutation compared to only 3 (3.6%) sequences with DRMinVs (P < .00001, Fisher exact test). Evidence of likely direct transmission of DRMajVs was observed for 25/66 (37.9%), whereas none were observed for the DRMinVs (P < .00001).

CONCLUSIONS

Using a densely sampled HIV-infected population, we show no evidence of DRMinV transmission among recently infected individuals.

Ultradeep sequencing reveals HIV-1 diversity and resistance compartmentalization during HIV-encephalopathy

OBJECTIVES

To examine viral diversity and resistance mutations in different brain areas in cases of HIV-encephalopathy.

DESIGN

Twelve postmortem brain areas from three cases of possible or certain HIV-encephalopathy were analyzed.

METHODS

After amplification of the reverse transcriptase and the V3 loop region of the gp120 protein, ultradeep sequencing was performed with Illumina technology. Phylogenetic analysis was performed with Fastree v2.1 using the generalized time-reversible (GTR) model. Identification of resistant viral variants was performed on Geneious software, according to HIV-1 genotypic drug resistance interpretation's algorithms, 2018 administered by the French Agency for Research on AIDS and Viral Hepatitis.

RESULTS

Phylogenetic analysis revealed significant inter-regional and intra-regional diversity reflecting persistent HIV-1 viral replication in the different brain areas. Although some cerebral regions shared HIV-variants, most of them harbored a specific HIV-subpopulation reflecting HIV compartmentalization in the central nervous system. Furthermore, proportion and distribution of resistance mutations to nucleoside and non-nucleoside reverse transcriptase inhibitors differed among different brain areas of the same case suggesting that penetration of antiretroviral treatment may differ from one compartment to another.

CONCLUSION

This study, performed with a powerful sequencing technique, confirmed HIV compartmentalization in the central nervous system already shown by classical sequencing, suggesting that there are several reservoirs within the brain.

Diagnostic Accuracy of Pan-Degenerate Amplification and Adaptation Assay for HIV-1 Drug Resistance Mutation Analysis in Low- and Middle-Income Countries

HIV drug resistance (HIVDR) is a barrier to sustained virologic suppression in low- and middle-income countries (LMICs). Point mutation assays targeting priority drug resistance mutations (DRMs) are being evaluated to improve access to HIVDR testing. In a cross-sectional study (June 2018 to September 2019), we evaluated the diagnostic accuracy of a simple and rapid HIVDR assay (the pan-degenerate amplification and adaptation [PANDAA] assay targeting the mutations K65R, K103NS, M184VI, Y181C, and G190A) compared to Sanger sequencing and next-generation sequencing (NGS). Plasma samples from adolescents and young adults (aged 10 to 24 years) failing antiretroviral therapy (viral load, >1,000 copies/ml on 2 consecutive occasions 1 month apart) were analyzed. Sensitivity and specificity of the PANDAA assay were determined by a proprietary application designed by Aldatu Biosciences. Agreement between genotyping methods was evaluated using Cohen's kappa coefficient. One hundred fifty samples previously characterized by Sanger sequencing were evaluated using PANDAA. For all DRMs detected, PANDAA showed a sensitivity and specificity of 98% and 94%, respectively. For nucleotide reverse transcriptase inhibitor DRMs, sensitivity and specificity were 98% (95% confidence interval [CI], 92% to 100%) and 100% (94% to 100%), respectively. For non-nucleotide reverse transcriptase inhibitor DRMs, sensitivity and specificity were 100% (97% to 100%) and 76% (61% to 87%), respectively. PANDAA showed strong agreement with Sanger sequencing for K65R, K103NS, M184VI, and G190A (kappa > 0.85) and substantial agreement for Y181C (kappa = 0.720). Of the 21 false-positive samples genotyped by PANDAA, only 6 (29%) were identified as low-abundance variants by NGS. With the high sensitivity and specificity to detect major DRMs, PANDAA could represent a simple and rapid alternative HIVDR assay in LMICs.

Detection of pretreatment minority HIV-1 reverse transcriptase inhibitor-resistant variants by ultra-deep sequencing has a limited impact on virological outcomes

OBJECTIVES

Ultra-deep sequencing (UDS) is a powerful tool for exploring the impact on virological outcome of minority variants with low frequencies, some even <1% of the virus population. Here, we compared HIV-1 minority variants at baseline, through plasma RNA and PBMC DNA analyses, and the dominant variants at the virological failure (VF) point, to evaluate the impact of minority drug-resistant variants (MDRVs) on virological outcomes.

METHODS

Single-molecule real-time sequencing (SMRTS) was performed on baseline RNA and DNA. The Stanford HIV-1 drug resistance database was used for the identification and evaluation of drug resistance-associated mutations (DRAMs).

RESULTS

We classified 50 patients into virological success (VS) and VF groups. We found that the rates of reverse transcriptase inhibitor (RTI) DRAMs determined by SMRTS did not differ significantly within or between groups, whether based on RNA or DNA analyses. There was no significant difference in the level of resistance to specific drugs between groups, in either DNA or RNA analyses, except for the DNA-based analysis of lamivudine, for which there was a trend towards a higher prevalence of intermediate/high-level resistance in the VF group. The RNA MDRVs corresponded to DNA MDRVs, except for M100I and Y188H. Sequencing from DNA appeared to be more sensitive than from RNA to detect MDRVs.

CONCLUSIONS

Detection of pretreatment minority HIV-1 RTI-resistant variants by UDS showed that MDRVs at baseline were not significantly associated with virological outcome. However, HIV-1 DNA sequencing by UDS was useful for detecting pretreatment drug resistance mutations in patients, potentially affecting virological responses, suggesting a potential clinical relevance for ultra-deep DNA sequencing.

Near Real-Time Identification of Recent Human Immunodeficiency Virus Transmissions, Transmitted Drug Resistance Mutations, and Transmission Networks by Multiplexed Primer ID-Next-Generation Sequencing in North Carolina

BACKGROUND

The identification of recent human immunodeficiency virus (HIV) 1 infections among people with new HIV diagnoses is important to both tailoring and assessing the impact of HIV-1 prevention strategies.

METHODS

We developed a multiplexed Primer ID-next-generation sequencing approach to identify recent infections by measuring the intrahost viral diversity over multiple regions of the HIV-1 genome, in addition to detecting drug resistance mutations (DRMs) and phylogenetically linked clusters. We summarize the field implementation of this all-in-one platform among persons with newly diagnosed HIV-1 by the North Carolina State Laboratory of Public Health in 2018.

RESULTS

Overall, recent infection was identified in 94 (35%) of 268 patients with new HIV diagnoses. People <30 years old, and people who inject drugs were more likely to have diagnoses of recent infection. The reverse-transcriptase region K103N was the most commonly detected DRM (prevalence, approximately 15%). We found a total of 28 clusters, and persons with recent infection were more likely to be cluster members than were those with chronic infections (P = .03).

CONCLUSIONS

We demonstrate the rapid identification of recent infection and pretreatment DRMs coupled with cluster analysis that will allow prioritization of linkage to care, treatment, and prevention interventions to those at highest risk of onward transmission.

Multi-Laboratory Comparison of Next-Generation to Sanger-Based Sequencing for HIV-1 Drug Resistance Genotyping

Next-generation sequencing (NGS) is increasingly used for HIV-1 drug resistance genotyping. NGS methods have the potential for a more sensitive detection of low-abundance variants (LAV) compared to standard Sanger sequencing (SS) methods. A standardized threshold for reporting LAV that generates data comparable to those derived from SS is needed to allow for the comparability of data from laboratories using NGS and SS. Ten HIV-1 specimens were tested in ten laboratories using Illumina MiSeq-based methods. The consensus sequences for each specimen using LAV thresholds of 5%, 10%, 15%, and 20% were compared to each other and to the consensus of the SS sequences (protease 4-99; reverse transcriptase 38-247). The concordance among laboratories' sequences at different thresholds was evaluated by pairwise sequence comparisons. NGS sequences generated using the 20% threshold were the most similar to the SS consensus (average 99.6% identity, range 96.1-100%), compared to 15% (99.4%, 88.5-100%), 10% (99.2%, 87.4-100%), or 5% (98.5%, 86.4-100%). The average sequence identity between laboratories using thresholds of 20%, 15%, 10%, and 5% was 99.1%, 98.7%, 98.3%, and 97.3%, respectively. Using the 20% threshold, we observed an excellent agreement between NGS and SS, but significant differences at lower thresholds. Understanding how variation in NGS methods influences sequence quality is essential for NGS-based HIV-1 drug resistance genotyping.

Next-Generation Sequencing for HIV Drug Resistance Testing: Laboratory, Clinical, and Implementation Considerations

Higher accessibility and decreasing costs of next generation sequencing (NGS), availability of commercial kits, and development of dedicated analysis pipelines, have allowed an increasing number of laboratories to adopt this technology for HIV drug resistance (HIVDR) genotyping. Conventional HIVDR genotyping is traditionally carried out using population-based Sanger sequencing, which has a limited capacity for reliable detection of variants present at intra-host frequencies below a threshold of approximately 20%. NGS has the potential to improve sensitivity and quantitatively identify low-abundance variants, improving efficiency and lowering costs. However, some challenges exist for the standardization and quality assurance of NGS-based HIVDR genotyping. In this paper, we highlight considerations of these challenges as related to laboratory, clinical, and implementation of NGS for HIV drug resistance testing. Several sources of variation and bias occur in each step of the general NGS workflow, i.e., starting material, sample type, PCR amplification, library preparation method, instrument and sequencing chemistry-inherent errors, and data analysis options and limitations. Additionally, adoption of NGS-based HIVDR genotyping, especially for clinical care, poses pressing challenges, especially for resource-poor settings, including infrastructure and equipment requirements and cost, logistic and supply chains, instrument service availability, personnel training, validated laboratory protocols, and standardized analysis outputs. The establishment of external quality assessment programs may help to address some of these challenges and is needed to proceed with NGS-based HIVDR genotyping adoption.

Impact of the mutational load on the virological response to a first-line rilpivirine-based regimen

OBJECTIVES

To determine how the load of rilpivirine-resistant variants (mutational load) influences the virological response (VR) of HIV-1-infected patients to a rilpivirine-based first-line regimen.

PATIENTS AND METHODS

Four hundred and eighty-nine patients infected with HIV-1 whose reverse transcriptase gene had been successfully resistance genotyped using next-generation sequencing were given a first-line regimen containing rilpivirine. Variables associated with the VR at 12 months were identified using a logistic model. The results were used to build a multivariate model for each mutational load threshold and the R2 variations were analysed to identify the mutational load threshold that best predicted the VR.

RESULTS

The mutational load at baseline was the only variable linked to the VR at 12 months (P  < 0.01). The VR at 12 months decreased from 96.9% to 83.4% when the mutational load was >1700 copies/mL and to 50% when the mutational load was > 9000 copies/mL. The threshold of 9000 copies/mL was associated with the VR at 12 months with an OR of 36.7 (95% CI 4.7-285.1). The threshold of 1700 copies/mL was associated with the VR at 12 months with an OR of 7.2 (95% CI 1.4-36.8).

CONCLUSIONS

There is quantifiable evidence that determining a mutational load threshold can be used to identify those patients on a first-line regimen containing rilpivirine who are at risk of virological failure. The clinical management of HIV-infected patients can be improved by evaluating the frequency of mutant variants at a threshold of < 20% together with the plasma HIV-1 viral load at the time of resistance genotyping.

Are We Ready for NGS HIV Drug Resistance Testing? The Second "Winnipeg Consensus" Symposium

HIV drug resistance is a major global challenge to successful and sustainable antiretroviral therapy. Next-generation sequencing (NGS)-based HIV drug resistance (HIVDR) assays enable more sensitive and quantitative detection of drug-resistance-associated mutations (DRMs) and outperform Sanger sequencing approaches in detecting lower abundance resistance mutations. While NGS is likely to become the new standard for routine HIVDR testing, many technical and knowledge gaps remain to be resolved before its generalized adoption in regular clinical care, public health, and research. Recognizing this, we conceived and launched an international symposium series on NGS HIVDR, to bring together leading experts in the field to address these issues through in-depth discussions and brainstorming. Following the first symposium in 2018 (Winnipeg, MB Canada, 21-22 February, 2018), a second "Winnipeg Consensus" symposium was held in September 2019 in Winnipeg, Canada, and was focused on external quality assurance strategies for NGS HIVDR assays. In this paper, we summarize this second symposium's goals and highlights.

A single variant sequencing method for sensitive and quantitative detection of HIV-1 minority variants

HIV drug resistance is a major threat to achieving long-term viral suppression in HIV-positive individuals. Drug resistant HIV variants, including minority variants, can compromise response to antiretroviral therapy. Many studies have investigated the clinical relevance of drug resistant minority variants, but the level at which minority variants become clinically relevant remains unclear. A combination of Primer-ID and deep sequencing is a promising approach that may quantify minority variants more accurately compared to standard deep sequencing. However, most studies that used the Primer-ID method have analyzed clinical samples directly. Thus, its sensitivity and quantitative accuracy have not been adequately validated using known controls. Here, we constructed defined proportions of artificial RNA and virus quasispecies and measured their relative proportions using the Primer-ID based, quantitative single-variant sequencing (qSVS) assay. Our results showed that minority variants present at 1% of quasispecies were detected reproducibly with minimal variations between technical replicates. In addition, the measured frequencies were comparable to the expected frequencies. These data validate the accuracy and reproducibility of the qSVS assay in quantifying authentic HIV minority variants, and support the use of this approach to examine the impacts of minority HIV variants on virologic response and clinical outcome.