894. Trend of Transmitted Resistance Associated Mutations in People Living with HIV (PLWH) in a Large Southeastern U.S. Ryan White Clinic

Background Department of Health and Human Services (DHHS) guidelines recommend integrase strand transfer inhibitors (INSTIs) as the backbone of preferred initial antiretroviral (ART) regimens (1). Baseline mutation rates for the INSTI class is 0.8% compared with an overall rate of 19% for all ART classes, based on Centers for Disease Control and Prevention (CDC) U.S. data from 2013-16 (2). First-generation INSTIs (raltegravir and elvitegravir) have a lower genetic barrier to resistance compared with newer, second generation INSTIs (bictegravir and dolutegravir) (3, 4). DHHS guidelines do not currently recommend routine HIV genotypic resistance testing to INSTIs prior to ART initiation (1). Our study seeks to determine the current prevalence of transmitted INSTI and overall resistance in a large southeastern U.S. Ryan White clinic. Methods This was a single-center, retrospective analysis of treatment naïve PLWH presenting for care from January 1, 2017 to December 31, 2020. Of these, 164 had a baseline genotype performed by one of two commercially available assays – Vela Genomics or ViroSeq. Subsequent interpretations were based on Stanford HIV Drug Resistance Database. Results 65 patients (39.6%) had at least one transmitted resistance associated mutation (RAMs). Of these, 24 (36.9%) had an INSTI RAM. Baseline PI, NRTI, and NNRTI RAMs declined during the four-year interval (2017-2020), while the rate of INSTI RAMs increased from 11.1% to 19%; all conferred resistance to the first generation INSTIs with one also conferring resistance to second generation INSTIs. INSTI Resistance Associated Mutation Prevalence 2017-2020 Frequency of Antiretroviral Therapy Class Mutations Per Year Trend of INSTI Mutations and Resistance Associated Mutations 2017-2020 Conclusion Unlike the CDC data which showed the overall prevalence of INSTI RAM transmission rates during 2013-2016 to be 0.8%, our data suggests a higher rate of INSTI RAMs (14.6%) with overall ART RAM transmission of 39.6%. This increase in baseline resistance to the INSTI class, which occurred over time, mimics the historical development of RAMs seen in the earlier ART classes. Though suboptimal adherence in the population promotes development of RAMs, increased frequency of INSTI RAMs may be due to a lower barrier to resistance of first generation INSTIs. Should our observed trend continue, routine baseline INSTI resistance testing may need to be considered prior to ART initiation. Disclosures Cheryl Newman, MD, Gilead (Scientific Research Study Investigator)GSK/ViiV (Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau)Janssen (Scientific Research Study Investigator)Merck (Scientific Research Study Investigator)

HIV-1 Subtype C Drug Resistance Mutations in Heavily Treated Patients Failing Integrase Strand Transfer Inhibitor-Based Regimens in Botswana

There are limited real-world mutational and virological outcomes data of treatment-experienced persons diagnosed with HIV-1 subtype C (HIV-1 C) who are failing Integrase Strand Transfer Inhibitor-based regimens. Requisition forms sent for HIV-1 genotypic resistance testing (GRT) between May 2015 and September 2019 were reviewed and participants experiencing virologic failure while on dolutegravir (DTG) or raltegravir (RAL) cART at sampling recruited. Sanger sequencing of the HIV-1 Pol gene was performed from residual plasma samples and drug resistance mutational (DRM) analysis performed using the Stanford University HIV drug resistance database. 40 HIV-1C integrase sequences were generated from 34 individuals, 24 of whom were on DTG cART, three on RAL cART and seven on an unknown (DTG or RAL)-anchored cART at time of GRT. 11/34 (32%) individuals had DRMs to DTG and other integrase inhibitors. 7/11 (64%) patients had exposure to a RAL-based cART at the time of sampling. Out of the 11 individuals with DRMs, one (9%) had 2-class, 6 (55%) had 3-class, and 4 (36%) had 4-class multidrug-resistant HIV-1C. 7/11 individuals (64%) are currently virologically suppressed. Of the four individuals not virologically suppressed, three had extensive DRMs involving 4-classes of ARV drugs and one individual has demised. Resistance to DTG occurs more often in patients exposed to RAL cART. Individuals with 4-class DRMs plus integrase T97 and E157Q mutations appear to have worse outcomes. There is a need for frequent VL monitoring and GRT amongst treatment-experienced HIV-1C diagnosed individuals.

Drug Resistance Mutations Among South African Children Living With HIV on WHO-recommended ART Regimens

Background Children living with human immunodeficiency virus (HIV) (CLHIV) receiving antiretroviral therapy (ART) in resource-limited settings are susceptible to high rates of acquired HIV drug resistance (HIVDR), but few studies include children initiating age-appropriate World Health Organization (WHO)-recommended first-line regimens. We report data from a cohort of ART-naive South African children who initiated first-line ART. Methods ART-eligible CLHIV aged 0–12 years were enrolled from 2012 to 2014 at 5 public South African facilities and were followed for up to 24 months. Enrolled CLHIV received standard-of-care WHO-recommended first-line ART. At the final study visit, a dried blood spot sample was obtained for viral load and genotypic resistance testing. Results Among 72 successfully genotyped CLHIV, 49 (68.1%) received ABC/3TC/LPV/r, and 23 (31.9%) received ABC/3TC/EFV. All but 2 children on ABC/3TC/LPV/r were <3 years, and all CLHIV on ABC/3TC/EFV were ≥3 years. Overall, 80.6% (58/72) had at least one drug resistance mutation (DRM). DRMs to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) were found among 65% and 51% of all CLHIV, respectively, with no statistical difference by ART regimen. More CLHIV on ABC/3TC/EFV, 47.8% (11/23), were found to have 0 or only 1 effective antiretroviral drug remaining in their current regimen compared to 8.2% (4/49) on ABC/3TC/LPV/r. Conclusions High levels of NNRTI and NRTI DRMs among CLHIV receiving ABC/3TC/LPV/r suggests a lasting impact of failed mother-to-child transmission interventions on DRMs. However, drug susceptibility analysis reveals that CLHIV with detectable viremia on ABC/3TC/LPV/r are more likely to have maintained at least 2 effective agents on their current HIV regimen than those on ABC/3TC/EFV.

Characterization of viral rebounds on dual etravirine/raltegravir maintenance therapy (ANRS-163 ETRAL trial)

Background The ANRS-163 ETRAL trial, a switch study to an etravirine 200 mg/raltegravir 400 mg twice-daily regimen in 165 patients with HIV-1 infection, showed durable efficacy until Week 96. The aim of this work was to investigate in detail the virological rebounds (VRs), defined as at least one plasma HIV viral load (VL) >50 copies/mL. Methods Quantification of HIV-DNA level was assessed at baseline, Week 48 and Week 96 (n = 157). VLs were measured in seminal plasma at Week 48 (n = 26). Genotypic resistance testing by ultra-deep sequencing (UDS) for reverse transcriptase (RT) and integrase regions was performed at baseline and at the time of VR. Results In this study, 19 patients experienced VR, with 2 patients having virological failure (VF; two consecutive VLs >50 copies/mL). For the first patient with VF, UDS detected minority resistant variants only in RT (K103N, 9.6%; Y181C, 4.9%) at baseline. Some RT variants became dominant at VF (K101E, 86.3%; Y181C, 100.0%; G190A, 100.0%) and others emerged in integrase (Y143C, 2.4%; Q148R, 6.2%; N155H, 18.8%). For the second patient with VF, neither RT nor integrase mutations were detected at baseline and VF. Median HIV-DNA level was similar at baseline, Week 48 and Week 96 (2.17, 2.06 and 2.11 log10 copies/106 cells, respectively). Only one patient had a detectable seminal HIV VL (505 copies/mL). Conclusions The dual etravirine/raltegravir regimen as maintenance therapy was effective and the emergence of mutations in cases of VF was similar to that seen in other dual-regimen studies. No HIV-DNA level modification was evidenced by Week 96.

Successful establishment of third-line antiretroviral therapy in Malawi: lessons learned

Setting: Malawi has an extensive national antiretroviral treatment (ART) program, and although less than 2% of all patients receive second-line ART, there are increasingly more patients failing on these regimens.Objective: To establish a virtual ART committee using limited available local facilities and expertise to recommend third-line regimens based on genotype resistance of samples sent abroad.Design: A secretariat and a laboratory sample hub were established. The committee started work after locally organizing training courses. Decisions about ART regimens were mainly based on a relatively simple, previously described algorithm, which allowed decisions to be taken without extensive expert knowledge.Results: Of the 25 applications assessed, 23 samples were sent for resistance testing from June 2017 to April 2018. Major protease inhibitor (PI) resistance was detected in 65% of the samples. PI resistance was found even in patients exposed to PIs for short periods. In particular, patients who received co-administration of PIs and rifampicin frequently showed resistance mutations.Conclusion: Third-line ART using genotypic resistance testing and algorithm-based treatment regimens are feasible in low-resource settings. Our model can serve as a base for similar programs initiating programmatic third-line ART in other African countries.

Analysis of unusual and signature APOBEC-mutations in HIV-1 pol next-generation sequences

ABSTRACTIntroductionAt low mutation-detection thresholds, next generation sequencing (NGS) for HIV-1 genotypic resistance testing is susceptible to artifactual detection of mutations arising from PCR error and APOBEC-mediated G-to-A hypermutation.MethodsWe analyzed published HIV-1 pol Illumina NGS data to characterize the distribution of mutations at eight NGS thresholds: 20%, 10%, 5%, 2%, 1%, 0.5%, 0.2%, and 0.1%. At each threshold, we determined the proportion of amino acid mutations that were unusual (defined as having a prevalence <0.01% in HIV-1 group M sequences) or were signature APOBEC mutations.ResultsEight studies, containing 855 samples, in the NCBI Sequence Read Archive were analyzed. As detection thresholds were lowered, there was a progressive increase in the proportion of positions with both usual and unusual mutations and in the proportion of all mutations that were unusual. The median proportion of positions with an unusual mutation increased gradually from 0% at the 20% threshold to 0.3% at the 1% threshold and then exponentially to 1.3% (0.5% threshold), 6.9% (0.2% threshold), and 23.2% (0.1% threshold). In two of three studies with available plasma HIV-1 RNA levels, the proportion of positions with unusual mutations was negatively associated with virus levels. Although the complete set of signature APOBEC mutations was much smaller than that of unusual mutations, the former outnumbered the latter in one-sixth of the samples at the 0.5%, 1%, and 2% thresholds.ConclusionsThe marked increase in the proportion of positions with unusual mutations at thresholds below 1% and in samples with lower virus loads suggests that, at low thresholds, many unusual mutations are artifactual, reflecting PCR error or G-to-A hypermutation. Profiling the numbers of unusual and signature APOBEC pol mutations at different NGS thresholds may be useful to avoid selecting a threshold that is too low and poses an unacceptable risk of identifying artifactual mutations.

A2 Phylogenetic investigation of transmitted HIV-1 drug resistance mutations in Denmark, 2009–17

Transmission of HIV-1 resistance mutations among therapy-naïve patients impairs the efficiency of antiretroviral therapy (ART). Therefore, genotypic resistance testing of patients is recommended at baseline, as this both allows for the selection of the correct ART regimen and for surveillance of transmitted drug resistance mutations (TDRM) among therapy naive HIV-1 patients. In Denmark, the occurrence of TDRM in newly diagnosed and therapy naïve HIV-1 patients is monitored through the SERO project. Here, we investigated if the prevalence of TDRM differed between patients within and outside of phylogenetically identified transmission clusters. Samples from 1,227 newly diagnosed HIV-1 patients were sent along with epidemiological information to the Virological Surveillance and Research group at Statens Serum Institut. HIV-1 RNA extraction, RT-PCR and Sanger sequencing of the pol gene was performed using an in-house assay. The sequences were analyzed using BioNumerics v. 6.6 and manually checked for the presence of mixed mutations and analyzed for mutations using the HIVDB 8.4 algorithm implemented at the Stanford database. Sequence alignments were performed in Mafft, and phylogenetic analysis was performed using Mega 6.0 using the Maximum likelihood general time reversible model with 100 bootstrap replicates. Clusters were identified with ClusterPicker at default settings (cluster support = 90%, genetic distance 4.5%). Active clusters contained newly diagnosed patients from the 2015 to 2017 period. HIV-1 sequences from 588 patients belonged to one of 154 clusters, and sequences from 639 patients did not belong to a cluster. Patients in clusters were significantly more likely to be men who have sex with men and subtype B and significantly less likely to be late presenters (Fisher’s test P < 0.05). The TDRM prevalence was significantly higher for patients outside of clusters than within clusters, 16.6 per cent versus 12.1 per cent, respectively (Fisher’s test P < 0.05); however, no significant differences were found in the TDRM prevalence between the 75 active and 79 inactive clusters, nor between small (<3 patients) and large (≥3 patients) clusters. E138A, V179D, and K103N were the three most prevalent TDRMs for both patient groups, whereas M41L differed between them. In Denmark, the TDRM prevalence is lower within clusters than outside, indicating that TDRM cases are either imported and/or belong to yet unidentified clusters.