Switching to bictegravir/emtricitabine/tenofovir alafenamide maintained HIV-1 RNA suppression in participants with archived antiretroviral resistance including M184V/I

Twelve-month effectiveness and safety of bictegravir/emtricitabine/tenofovir alafenamide in people with HIV: Real-world insights from BICSTaR cohorts

BACKGROUND

Real-world evidence is an essential component of evidence-based medicine. The aim of the BICSTaR (BICtegravir Single Tablet Regimen) study is to assess effectiveness and safety of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in antiretroviral treatment-naïve (TN) and treatment-experienced (TE) people with HIV.

METHODS

BICSTaR is a prospective, observational cohort study. Participants (≥18 years) are being followed for 24 months. A pooled analysis is presented at 12 months, with the primary endpoint of effectiveness (HIV-1 RNA <50 copies/mL) and secondary endpoints of safety and tolerability (as per protocol). An exploration of patient-reported outcome measures using standardized questionnaires is included.

RESULTS

Between June 2018 and May 2021, 1552 people with HIV were enrolled across 12 countries. The analysed population comprised 1509 individuals (279 TN, 1230 TE); most were white (76%), male (84%) and had one or more comorbid conditions (68%). Median age was 47 years. After 12 months of B/F/TAF treatment, HIV-1 RNA was <50 copies/mL in 94% (221/236) of TN participants and 97% (977/1008) of TE participants. Median CD4 cell count increased by 214 cells/μL (p < 0.001) in TN participants and 13 cells/μL (p = 0.014) in TE participants; median CD4/CD8 ratios increased by 0.30 and 0.03, respectively (both p < 0.001). Persistence was high at 12 months (TN, 97%; TE, 95%). No resistance to B/F/TAF emerged. Study drug-related adverse events occurred in 13% of participants through 12 months, leading to B/F/TAF discontinuation in 6%.

CONCLUSIONS

The findings of this study provide robust real-world evidence to support the broad use of B/F/TAF in both TN and TE people with HIV.

Use of genotypic HIV DNA testing: a DELPHI-type consensus

OBJECTIVES

As many disparities in the clinical use of HIV DNA sequencing are observed, a DELPHI-type consensus was initiated in France to homogenize use, techniques and interpretation of results.

METHODS

Based on a literature review and clinical experience, a steering committee (SC) of eight virologists and one infectious disease specialist formulated statements. Statements were submitted to an independent and anonymous electronic vote of virologists and HIV clinicians in France, between October 2022 and December 2022.

RESULTS

The SC developed 20 statements grouped into six categories: clinical situations for the use of HIV DNA genotyping; techniques for performing HIV DNA genotyping; consideration of apolipoprotein B mRNA editing enzyme (APOBEC) mutations; genotyping results reporting; recycling of antiretrovirals; and availability of HIV DNA genotyping tests and delays. Twenty-one virologists and 47 clinicians participated in two voting rounds and 18/20 (90%) assertions reached a 'strong' consensus. For example, that prior genotyping on HIV DNA is useful for clinical decision-making when considering switching to some long-acting regimens or to reduce the number of antiretroviral agents in virologically suppressed patients for whom RNA data are unavailable/not exploitable/not sufficiently informative. Two statements achieved no consensus: reporting any detected viral minority population for discussion in multidisciplinary meetings (virologists), and possible risk of virological failure when using a second-generation InSTI plus lamivudine or emtricitabine regimen in patients with undetectable viral load within ≥1 year and in the presence of a documented M184V mutation within the last 5 years (clinicians).

CONCLUSIONS

This DELPHI-type consensus will facilitate the strengthening and harmonization of good practice when performing HIV DNA sequencing.

Real-life data of immune recovery using bictegravir/emtricitabine/tenofovir alafenamide in virologically suppressed people living with HIV. Results at 48-96 weeks of RETROBIC Study

BACKGROUND

Switching strategy with bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) has become a gold standard for people living with HIV (PLWH), achieving high efficacy and safety rates. However, data regarding immune status in long-term real-life cohorts of pretreated patients are needed.

METHODS

We performed a multicentre, non-controlled, retrospective study in virologically suppressed PLWH switching to B/F/TAF. We evaluated CD4+, CD8+ and CD4+/CD8+ ratio, efficacy and safety at weeks 48 and 96.

RESULTS

The study comprised 1966 PLWH from 12 hospitals in Spain, of whom 80% were men, and the median age was 51.0 [42.0-57.0] years. The median time of HIV infection was 18.0 [10.0-27.0] years. No significant changes in CD4+, CD8+ T cells, or CD4+/CD8+ were observed after 96 weeks. Nevertheless, in women at weeks 48 and 96, we found a significant increase of CD4+ T cells and a significant decrease in CD8+ T cells. In patients ≥60 years at week 96, CD4 T cells significantly increased and CD8+ T cells significantly decreased at week 48. The on-treatment analysis revealed HIV-RNA <50 copies/mL in 95.6% (1700/1779) and 96.7% (1312/1356) of patients at weeks 48 and 96, respectively. The rates increased to 99.2% (1765/1779) and 99.7% (1352/1356) when considering HIV-RNA <200 copies/mL. No resistance mutations were detected in virologic failures. B/F/TAF discontinuations accounted for 10.2% (200). Simplification was the most common reason for discontinuation in 3.8% (74) of patients.

CONCLUSION

In long-term virologically controlled PLWH, B/F/TAF achieved high efficacy rates and slightly improved immune status in women and individuals aged 60 and over after 48 and 96 of switching.

Bictegravir/emtricitabine/tenofovir alafenamide in paediatrics: Real-life experience from a French cohort (2019-2023)

OBJECTIVES

Although widely recommended, data on bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) efficacy in HIV-1-infected children/adolescents are mainly extrapolated from studies in adults and one paediatric trial in which subjects have good treatment adherence. This study aimed to provide data about the risk of virological failure (VF) and acquired genotypic resistance in children and adolescents receiving BIC/FTC/TAF in a real-world setting.

METHODS

This retrospective monocentric study included 74 paediatric patients who received BIC/FTC/TAF during ≥6 months in 2019-2023. VF was defined as not achieving a plasma viral load <50 copies/mL within 6 months of BIC/FTC/TAF initiation or as experiencing virological rebound ≥50 copies/mL.

RESULTS

Most patients were antiretroviral therapy (ART)-experienced (93.2%), previously exposed to integrase inhibitors (85.1%) and displayed viral suppression at baseline (67.6%). Their median age was 11.2 years [interquartile range (IQR): 8.8-15.2]. BIC/FTC/TAF introduction reduced treatment burden in most ART-experienced subjects. Genotypic susceptibility score of BIC/FTC/TAF was ≥2 in all cases. Median follow-up was 40 months (IQR: 21-46). VF occurred in 28 people (37.8%), more frequently in the case of VF versus viral suppression at baseline (68% vs. 26%, P = 0.02). BIC/FTC/TAF was interrupted for suspected intolerance in only one case (1.4%). Nucleoside reverse transcriptase inhibitor (NRTI) mutation (T69D/N) emerged in one patient (3.6% of VF) after 47 months of continuous detectable viraemia while on ART. No acquisition of mutations in the integrase gene was observed.

CONCLUSION

Because of its high genetic barrier to resistance, BIC/FTC/TAF could be especially useful in the paediatric population, in which the risk of poor treatment adherence and VF is high.

Bictegravir/Emtricitabine/Tenofovir Alafenamide for HIV-1: What is the Hidden Potential of This Emerging Treatment?

Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is a single-tablet antiretroviral therapy regimen. B/F/TAF has become a popular treatment choice because of its small tablet size, high barrier to resistance, favorable tolerability, and limited drug-drug interaction profile. Continued research on B/F/TAF has revealed additional potential for this regimen. This review presents recent literature supporting the use of B/F/TAF as an option for consolidating therapy and maintaining virologic suppression in individuals despite M184V/I mutations. Additionally, children are a unique patient population with limited antiviral options. Standard dose B/F/TAF has demonstrated similar drug exposure in children and adolescents as adults, and low-dose B/F/TAF is approved for children living with HIV greater than two years of age and weighing at least 14 kg. Data supporting this recommendation is described in this review. Finally, despite a lack of prospective data, B/F/TAF may have a role in the future of pre- and post-exposure prophylaxis. This review discusses these discoveries and the continued exploration of the hidden potential of B/F/TAF.

Treatment-emergent reverse transcriptase resistance during antiretroviral therapy with bictegravir, tenofovir alafenamide, and emtricitabine: A case series

OBJECTIVES

Bictegravir/tenofovir alafenamide/emtricitabine (BIC/TAF/FTC) is a complete regimen for the treatment of HIV with a high barrier to resistance and few reported cases of treatment failure. We present three cases of treatment-emergent resistance to nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) in patients with suboptimal treatment adherence and assess whether the resistance-associated mutations were present before BIC/TAF/FTC initiation or emerged during therapy.

METHODS

We used genotypic drug resistance testing by Sanger sequencing to identify emergent resistance mutations in plasma viral load specimens collected after combination antiretroviral therapy initiation in all participants. Additionally, we performed ultra-deep sequencing by Illumina MiSeq on the earliest available plasma HIV-1 viral load specimen and on any available specimens closest in time to the initiation of BIC/TAF/FTC therapy to identify low-abundance resistance mutations present in the viral quasispecies.

RESULTS

All three participants developed NRTI resistance after prolonged exposure and incomplete adherence to BIC/TAF/FTC. The T69N, K70E, M184I, and/or T215I mutations identified in clinical samples at the time of virological failure were not present on deep sequencing of either baseline samples or samples collected before BIC/TAF/FTC initiation.

CONCLUSIONS

Despite a generally high genetic barrier to resistance, NRTI resistance-associated mutations may emerge during therapy with BIC/TAF/FTC in the setting of suboptimal adherence.

Biktarvy for the treatment of HIV infection: Progress and prospects

Bictegravir (BIC), a second-generation integrase strand-transfer inhibitor (INSTI) with high resilience to INSTI-resistance mutations, is integrated as a key component of Biktarvy® - a fixed-dose once-daily triple-drug regimen of bictegravir (BIC), emtricitabine (FTC) plus tenofovir alafenamide (TAF). Based on the accumulated evidence from HIV clinical trials and real-world studies, the clinical effectiveness of BIC + FTC + TAF has been proven non-inferior to other fixed-dose once-daily combinations such as dolutegravir + FTC + TAF and dolutegravir + abacavir + lamivudine. Biktarvy also shows limited drug-drug interactions and a high barrier to drug resistance. According to recent HIV guidelines, BIC + FTC + TAF is recommended as initial and long-term therapy for the treatment of HIV infection. For the pre-exposure prophylaxis, tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) remains advisable, but BIC may be possibly added to TDF or TAF. In the development of a long-acting once-monthly regimen, the novel nano-formulation of BIC + FTC + TAF could be possibly developed in the future.

HIV drug resistance in the era of contemporary antiretroviral therapy: A clinical perspective

Contemporary antiretroviral therapy (ART) regimens have high barriers to the development of drug resistance. However, resistance to earlier antiretrovirals and uncommon cases of resistance to contemporary ART illustrate the continued need for good clinical management of HIV drug resistance. Here, we describe HIV drug-resistance mechanisms, the interaction of HIV drug-resistant mutations and the patterns of drug resistance to contemporary ART. We then provide guidance on the management of HIV drug resistance, including how to limit the development of resistance and manage virologic failure that is complicated by resistance. To complement this, links to resources and treatment guidelines are provided that can assist with the interpretation of HIV drug resistance test results and optimal ART selection in the clinic.

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.

Efficacy, durability, and tolerability of bictegravir/emtricitabine/tenofovir alafenamide for the treatment of HIV in a real-world setting in Belgium

OBJECTIVES

Our objective was to evaluate the efficacy, durability, and tolerability of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) in a real-world setting in Belgium.

METHODS

This was a retrospective, multicentre cohort study involving adult treatment-naïve (TN) and treatment-experienced (TE) people living with HIV receiving BIC/FTC/TAF between 1 January 2019 and 30 September 2020. The primary outcome was rate of virological suppression (plasma HIV-1 viral load <50 copies/mL; on-treatment analysis) at weeks 24 and 48. The main secondary outcomes included loss of virological suppression (LVS; two consecutive viral loads of >200 copies/mL after being virologically suppressed) by week 48 and analysis of resistance-associated mutations at time of LVS; tolerability of BIC/FTC/TAF over the 48-week study period; and change in weight and proportion of participants reporting a >10% weight gain at week 48.

RESULTS

Overall, 2001 participants were included. Through 48 weeks, overall rate of virological suppression was 93.5%, with similar results observed in the following subgroups: age ≥50 years (92.7%), women (92.8%), Black sub-Saharan African (91%), TN (94%), TE (93.2%), and non-suppressed at baseline (86.6%). LVS was observed in 0.7% (n = 14) of participants, with one participant developing resistance-associated mutations to nucleoside reverse transcriptase inhibitors (184 V) and integrase strand transfer inhibitors (263KR). Of the 131 (6.5%) treatment discontinuations, the most common reason was an adverse event (2.4%), with the most frequent being central nervous system/psychiatric (0.4%) and gastrointestinal (0.4%) toxicity. Median weight gain at week 48 was 2 kg (interquartile range -1 to 5), and a >10% weight increase was observed in 11.6% of participants.

CONCLUSION

In this large real-world cohort, BIC/FTC/TAF showed excellent virological efficacy in a diverse population of patients with HIV. Rare occurrence of emergent drug resistance was observed, and treatment was well tolerated.

Assessing the Virologic Impact of Archived Resistance in the Dolutegravir/Lamivudine 2-Drug Regimen HIV-1 Switch Study TANGO through Week 144

The TANGO study (ClinicalTrials.gov, NCT03446573) demonstrated that switching to dolutegravir/lamivudine (DTG/3TC) was non-inferior to continuing tenofovir alafenamide-based regimens (TBR) through week 144. Retrospective baseline proviral DNA genotypes were performed for 734 participants (post-hoc analysis) to assess the impact of archived, pre-existing drug resistance on 144-week virologic outcomes by last on-treatment viral load (VL) and Snapshot. A total of 320 (86%) participants on DTG/3TC and 318 (85%) on TBR had both proviral genotype data and ≥1 on-treatment post-baseline VL results and were defined as the proviral DNA resistance analysis population. Archived International AIDS Society-USA major nucleoside reverse transcriptase inhibitor, non-nucleoside reverse transcriptase inhibitor, protease inhibitor, and integrase strand transfer inhibitor resistance-associated mutations (RAMs) were observed in 42 (7%), 90 (14%), 42 (7%), and 11 (2%) participants, respectively, across both groups; 469 (74%) had no major RAMs at baseline. M184V/I (1%), K65N/R (<1%), and thymidine analogue mutations (2%) were infrequent. Through week 144, >99% of participants on DTG/3TC and 99% on TBR were virologically suppressed (last on-treatment VL <50 copies/mL) regardless of the presence of major RAMs. Results from the sensitivity analysis by Snapshot were consistent with the last available on-treatment VL. In TANGO, archived, pre-existing major RAMs did not impact virologic outcomes through week 144.

Immune Reconstitution and Safe Metabolic Profile after the Switch to Bictegravir/Emtricitabine/Tenofovir Alafenamide Fumarate among Virologically Controlled PLWH: A 96 Week Update from the BICTEL Cohort

BACKGROUND

Bictegravir/emtricitabine/tenofovir alafenamide fumarate (BIC/FTC/TAF) is a recommended once-daily single-tablet regimen for the treatment of people living with HIV (PLWH). We aimed to assess efficacy, safety, and tolerability of BIC/FTC/TAF among PLWH, with a specific focus on people older than 55 years.

METHODS

We recruited an observational retrospective real-life cohort, including all PLWH who underwent a therapeutic switch to BIC/FTC/TAF, independently from the previous treatment regimen (the BICTEL cohort). Longitudinal nonparametric analyses and linear models were built.

RESULTS

After 96 weeks of follow-up, 164 PLWH were included, with 106 older than 55. Both the intention-to-treat and the per-protocol analysis showed low rates of virologic failure, independent of the pre-switch anchor drug. At week 96, a significant increase in CD4⁺ T cell count and in CD4⁺/CD8⁺ ratio was observed, inversely correlated with baseline immune status. Fasting serum lipid profile, total body weight, BMI, and hepatic function were not affected by the switch, without new onset of metabolic syndrome or weight gain. Compared to baseline, we observed a renal function worsening which is worthy of further follow-up.

CONCLUSION

BIC/FTC/TAF is an effective, safe, and well-tolerated switching strategy for PLWH, especially among those older than 55.

Bictegravir/emtricitabine/tenofovir alafenamide in older individuals with HIV: Results of a 96-week, phase 3b, open-label, switch trial in virologically suppressed people ≥65 years of age

OBJECTIVES

Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is an effective treatment for HIV-1 infection; however, clinical trial data in older people living with HIV (PLWH) are lacking. The primary 24-week and secondary 48-week analyses of study GS-US-380-4449 (NCT03405935), which assessed the efficacy and safety of switching to B/F/TAF in older PLWH, have been published. Here we report the results of the final 96-week analyses from the study.

METHODS

In this 96-week, phase 3b, open-label, single-arm trial, virologically suppressed PLWH aged ≥65 years switched from elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide or a tenofovir disoproxil fumarate-based regimen to B/F/TAF. Viral suppression, resistance, immune response, safety, tolerability and adherence were evaluated through week 96.

RESULTS

Of 90 participants screened, 86 were enrolled and switched to B/F/TAF. No participants had HIV-1 RNA ≥50 copies/ml (by FDA Snapshot algorithm) at weeks 72 or 96; virologic suppression rates were 94.2% (81/86; 95% CI 87.0-98.1) and 74.4% (64/86; 95% CI 63.9-83.2), respectively. No treatment-emergent resistance was observed, and CD4 counts remained stable. There were no study drug-related serious adverse events. Three participants experienced drug-related treatment-emergent adverse events that led to premature drug discontinuation. There were no clinically relevant changes from baseline to week 96 in fasting lipid parameters, and the median change in body weight at week 96 was 0.0 kg (IQR -2.3, 2.0). Median self-reported adherence was 100% (IQR 100-100%).

CONCLUSIONS

Switching to B/F/TAF is an effective long-term option for virologically suppressed adults ≥65 years of age, with favourable safety and tolerability profiles in this population.

Switching to coformulated bictegravir, emtricitabine, and tenofovir alafenamide maintained viral suppression in adults with historical virological failures and K65N/R mutation

OBJECTIVES

Real-world experience with coformulated bictegravir, emtricitabine, and tenofovir alafenamide (BIC/FTC/TAF) is sparse as a switch regimen among people living with HIV (PLWH) having achieved viral suppression after previous virologic failures with the emergence of K65N/R.

METHODS

In this retrospective study, PLWH aged ≥20 years who had previous virologic failures with emergent K65N/R were included for switching to BIC/FTC/TAF after having achieved plasma HIV RNA load (PVL) <200 copies/ml for ≥3 months. PLWH were excluded if integrase inhibitor resistance-associated mutations were detected. The primary end point was losing virologic control (PVL >50 copies/ml) at week 48 using a modified US Food and Drug Administration snapshot algorithm.

RESULTS

A total of 72 PLWH with K65N/R who switched to BIC/FTC/TAF were identified. A total of 42 (59.7%) had concurrent M184V/I, and 9 (12.5%) had ≥1 thymidine analog mutations. The median duration of viral suppression was 4.7 years (interquartile range 2.3-5.8), and 97.2% (n = 70) had PVL <50 copies/ml before switching. After a median observation of 98.6 weeks (interquartile range 77.9-120.3), 94.4% (n = 68) continued BIC/FTC/TAF. At week 48, the rate of losing virologic control was 2.8% (2/72). M184V/I was not associated with viral rebound.

CONCLUSION

Despite the emergence of K65N/R +/- M184V/I after virologic failures, BIC/FTC/TAF could be an option for simplification after viral suppression.

Genotypic Resistance Testing of HIV-1 DNA in Peripheral Blood Mononuclear Cells

HIV-1 DNA exists in nonintegrated linear and circular episomal forms and as integrated proviruses. In patients with plasma viremia, most peripheral blood mononuclear cell (PBMC) HIV-1 DNA consists of recently produced nonintegrated virus DNA while in patients with prolonged virological suppression (VS) on antiretroviral therapy (ART), most PBMC HIV-1 DNA consists of proviral DNA produced months to years earlier. Drug-resistance mutations (DRMs) in PBMCs are more likely to coexist with ancestral wild-type virus populations than they are in plasma, explaining why next-generation sequencing is particularly useful for the detection of PBMC-associated DRMs. In patients with ongoing high levels of active virus replication, the DRMs detected in PBMCs and in plasma are usually highly concordant. However, in patients with lower levels of virus replication, it may take several months for plasma virus DRMs to reach detectable levels in PBMCs. This time lag explains why, in patients with VS, PBMC genotypic resistance testing (GRT) is less sensitive than historical plasma virus GRT, if previous episodes of virological failure and emergent DRMs were either not prolonged or not associated with high levels of plasma viremia. Despite the increasing use of PBMC GRT in patients with VS, few studies have examined the predictive value of DRMs on the response to a simplified ART regimen. In this review, we summarize what is known about PBMC HIV-1 DNA dynamics, particularly in patients with suppressed plasma viremia, the methods used for PBMC HIV-1 GRT, and the scenarios in which PBMC GRT has been used clinically.

Impact of preexisting nucleos(t)ide reverse transcriptase inhibitor resistance on the effectiveness of bictegravir/emtricitabine/tenofovir alafenamide in treatment experience patients

INTRODUCTION

Few clinical trials and cohort studies have evaluated the efficacy of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in people with HIV (PWH) with preexisting M184V/I or other nucleos(t)ide reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs). Real-world data are also scarce.

METHODS

Retrospective review of treatment-experienced patients who started B/F/TAF in a cohort of PWH. HIV-RNA less than 50 copies/ml was analyzed at 48 weeks in an intention-to-treat (ITT) analysis (missing=failure) and per protocol analysis (patients with missing data or changes for reasons other than virological failure were excluded). Results were compared in patients with and without previous NRTI-RAMs.

RESULTS

Five hundred and six PWH were included (16.2% women). Median age and time with HIV infection were 52.3 and 18.9 years, respectively. At baseline, viral load was less than 50 copies/ml in 440 patients (86.6%). Overall, 69 (13.6%) participants had documented preexisting NRTI-RAMs: 57 (11.2%) M184V/I and 30 (5.9%) tenofovir RAMs. In the ITT analysis, 83% (420/506) had HIV-RNA less than 50 copies/ml [82.2% (359/437) and 88.4% (61/69) in persons without and with NRTI-RAMs, respectively ( P  = 0.2)]. In the per protocol analysis 94.2% (420/445) had HIV-RNA less than 50 copies/ml [94.4% (359/380) vs. 93.8% (61/65); P  = 0.2]. A total of 61 participants were excluded from the per protocol analysis (23 missing data, 19 discontinued B/F/TAF because of toxicity, 13 for other reasons, and 6 died).

CONCLUSION

Switching to B/F/TAF is well tolerated and effective in the real-world setting, even in patients with preexisting NRTI RAMs, such as M184V and RAMs conferring resistance to tenofovir. These results confirm the robustness of this combination.

HIV DNA Sequencing to Detect Archived Antiretroviral Drug Resistance

INTRODUCTION

Proviral HIV DNA integrated within CD4 T-cells maintains an archive of viral variants that replicate during the course of the infection, including variants with reduced drug susceptibility. We considered studies that investigated archived drug resistance, with a focus on virologically suppressed patients and highlighted interpretative caveats and gaps in knowledge.

RESULTS

Either Sanger or deep sequencing can be used to investigate resistance-associated mutations (RAMs) in HIV DNA recovered from peripheral blood. Neither technique is free of limitations. Furthermore, evidence regarding the establishment, maintenance, expression and clinical significance of archived drug-resistant variants is conflicting. This in part reflects the complexity of the HIV proviral landscape and its dynamics during therapy. Clinically, detection of RAMs in cellular HIV DNA has a variable impact on treatment outcomes, modulated by the drugs affected, treatment duration and additional determinants of virological failure, including those leading to suboptimal drug exposure.

CONCLUSIONS

Sequencing cellular HIV DNA can provide helpful complementary information in treatment-experienced patients with suppressed plasma HIV RNA who require a change of regimen. However, care should be taken when interpreting the results. Presence of RAMs is not necessarily a barrier to treatment success. Conversely, even the most sensitive sequencing techniques will fail to provide a comprehensive view of the HIV DNA archive. To inform treatment decisions appropriately, the overall clinical and treatment history of a patient must always be considered alongside the results of resistance testing. Prospective controlled studies are needed to validate the utility of drug resistance testing using cellular HIV DNA.

Impact of pre-existent drug resistance on virological efficacy of single tablet regimens in people living with HIV

Despite the broad use of single tablet regimens (STRs), few real-life data are available regarding the impact of pre-existent drug resistance on virological failure (VF). Through this study we aimed to fill this gap, by analyzing a large cohort of individuals selected from the ARCA database. The impact on VF of pre-existent resistance associated mutations (RAMs) and cumulative genotypic susceptibility score (cGSS) before STR start was evaluated through survival analysis. Potential emergence of resistance at VF was also evaluated. Overall, 3916 individuals were included: 678 treatment-naïve (G1), 2309 treatment-experienced aviremic (G2), and 929 viremic (G3); 65.2% of them was treated with an STR based on efavirenz (35.2%) or rilpivirine (30%). At two years after starting STR, the overall probability of VF was 5.9% in G1, 8.7% in G2, and 20.8% in G3. No impact of pre-existent resistance on VF was found in G1. The probability of VF was higher in patients with cGSS<3 (reduced susceptibility to at least one drug) than in those with cGSS=3 (full susceptibility to STR drugs) in both G2 and G3. A higher probability of VF was also found in presence of pre-existent M184V (alone or in combination with pre-existent thymidine analogue mutations). Among patients who failed STR, a significant emergence of RAMs was found only in those exposed to EFV/FTC/TDF in G3 (specifically K103N and M184V). Our results confirm a high efficacy of STRs in clinical settings. Pre-existent resistance seems to influence virological efficacy of STR in treatment-experienced individuals (both aviremic and viremic).

HIV drug resistance in various body compartments

PURPOSE OF REVIEW

HIV drug resistance testing using blood plasma or dried blood spots forms part of international guidelines. However, as the clinical utility of assessing drug resistance in other body compartments is less well established, we review this for blood cells and samples from other body compartments.

RECENT EVIDENCE

Although clinical benefit is not clear, drug resistance testing in blood cells is often performed when patients with suppressed plasma viral loads require a treatment substitution. In patients with HIV neurocognitive disease, cerebral spinal fluid (CSF) drug resistance is rarely discordant with plasma but has nevertheless been used to guide antiretroviral drug substitutions. Cases with HIV drug resistance in genital fluids have been documented but this does not appear to indicate transmission risk when blood plasma viral loads are suppressed.

SUMMARY

Drug-resistant variants, which may be selected in tissues under conditions of variable adherence and drug penetration, appear to disseminate quickly, and become detectable in blood. This may explain why drug resistance discordance between plasma and these compartments is rarely found. Partial compartmentalization of HIV populations is well established for the CSF and the genital tract but other than blood plasma, evidence is lacking to support drug resistance testing in body compartments.

Low-level viremia and virologic failure among people living with HIV who received maintenance therapy with co-formulated bictegravir, emtricitabine and tenofovir alafenamide versus dolutegravir-based regimens

BACKGROUND

Real-world experience with low-level viremia (LLV) and its impact remain less reported among people living with HIV (PLWH) who receive antiretroviral therapy (ART) containing second-generation integrase strand transferase inhibitors (INSTIs), including dolutegravir and bictegravir.

METHODS

Virally suppressed PLWH who had achieved plasma HIV RNA load (PVL) <50 copies/mL for ≥6 months and were switched to either dolutegravir- or bictegravir-based ART were included in this retrospective cohort study. The incidence rates of developing LLV events (PVL, 50-199 copies/mL) and virologic failure (VF) (PVL ≥1000 copies/mL) were compared between the dolutegravir and bictegravir cohorts.

RESULTS

A total of 623 and 862 PLWH switched to dolutegravir-based and bictegravir-based ART, respectively, were included. The incidence rates of developing LLV were 6.2 per 100 person-years of follow-up (PYFU) in the bictegravir cohort and 3.8 per 100 PYFU in the dolutegravir cohort (incidence rate ratio [IRR], 1.63; 95% confidence interval [CI], 0.90-2.95, p=0.08), while the rates of VF were 0.69 per 100 PYFU and 0.95 per 100 PYFU, respectively, in the bictegravir and dolutegravir cohort (IRR, 0.72; 95% CI, 0.12-3.39, p=0.34). Presence of LLV events was not associated with subsequent VF in multivariate analysis. Secondary analysis also demonstrated that resistance-associated mutations (RAMs) to nucleoside reverse-transcriptase inhibitors before switch were not associated with adverse virologic outcomes in either cohort.

CONCLUSIONS

Among virally suppressed PLWH, the incidences of developing LLV or VF were similar after switch to dolutegravir- or bictegravir-based ART. Preexisting RAMs to nucleoside reverse-transcriptase inhibitors or the LLV events were not associated with subsequent VF.

Brief Report: Bictegravir/Emtricitabine/Tenofovir Alafenamide Efficacy in Participants With Preexisting Primary Integrase Inhibitor Resistance Through 48 Weeks of Phase 3 Clinical Trials

BACKGROUND

Preexisting drug resistance limits the utility of HIV antiretroviral therapy. Studies have demonstrated safety and efficacy of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF), including in patients with M184V/I substitutions.

SETTING

We investigated virologic outcomes through 48 weeks of B/F/TAF treatment in individuals with preexisting primary integrase strand transfer inhibitor resistance (INSTI-R).

METHODS

Preexisting INSTI-R was retrospectively evaluated from 7 B/F/TAF studies. INSTI-R was assessed by historical genotypes and/or baseline RNA or DNA sequencing. Viral loads were measured at all visits.

RESULTS

Preexisting primary INSTI-R substitutions were detected in 20 of the 1907 participants (1.0%). The 20 participants were predominantly male (75%), were Black (65%), had HIV-1 subtype B (85%), and had baseline median CD4 counts of 594 cells/mm3 and median age of 52 years. Most of the participants (n = 19) were virologically suppressed at baseline and had one primary INSTI-R substitution, E92G, Y143C/H, S147G, Q148H/K/R, N155S, or R263K, +/-secondary substitutions. All suppressed participants maintained virologic suppression throughout 48 weeks without any viral blips. One treatment-naive participant had virus with Q148H+G140S that was fully sensitive to bictegravir but only partially to dolutegravir (phenotype <2.5-fold change and >4-fold change, respectively). With a baseline viral load of 30,000 copies/mL, this participant was virologically suppressed by week 4 and maintained <50 copies/mL through week 48.

CONCLUSIONS

This small cohort with primary INSTI-R achieved and/or maintained virologic suppression through 48 weeks of B/F/TAF treatment. Consistent with the potent in vitro activity of bictegravir against most INSTI-R patterns, B/F/TAF may be a potential treatment option for patients with select preexisting INSTI-R, if confirmed by further studies.

Pre-Treatment Integrase Inhibitor Resistance and Natural Polymorphisms among HIV-1 Subtype C Infected Patients in Ethiopia

Dolutegravir-based antiretroviral therapy (ART) has been scaled up in many developing countries, including Ethiopia. However, subtype-dependent polymorphic differences might influence the occurrence of HIV-drug-resistance mutations (HIVDRMs). We analyzed the prevalence of pre-treatment integrase strand transfer inhibitor (INSTI) HIVDRMs and naturally occurring polymorphisms (NOPs) of the integrase gene, using plasma samples collected as part of the national HIVDR survey in Ethiopia in 2017. We included a total of 460 HIV-1 integrase gene sequences from INSTI-naïve (n = 373 ART-naïve and n = 87 ART-experienced) patients. No dolutegravir-associated HIVDRMs were detected, regardless of previous exposure to ART. However, we found E92G in one ART-naïve patient specimen and accessory mutations in 20/460 (4.3%) of the specimens. Moreover, among the 288 integrase amino acid positions of the subtype C, 187/288 (64.9%) were conserved (<1.0% variability). Analysis of the genetic barrier showed that the Q148H/K/R dolutegravir resistance pathway was less selected in subtype C. Docking analysis of the dolutegravir showed that protease- and reverse-transcriptase-associated HIVDRMs did not affect the native structure of the HIV-1 integrase. Our results support the implementation of a wide scale-up of dolutegravir-based regimes. However, the detection of polymorphisms contributing to INSTI warrants the continuous surveillance of INSTI resistance.

Real-life experience with bictegravir/emtricitabine/tenofovir alafenamide in a large reference clinical centre

BACKGROUND

The use of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) is mainly based on robust, pivotal clinical trials.

OBJECTIVES

To provide data on clinical use of BIC/FTC/TAF in real life.

PATIENTS AND METHODS

This was an observational, retrospective and single-centre study. We included all adult, treatment-naive (TN) and treatment-experienced (TE) people living with HIV (PLWH) starting BIC/FTC/TAF from 8 June 2018. We evaluated effectiveness [on treatment (OT), modified intention-to-treat (mITT) and intention-to-treat (ITT)], tolerability and safety in those patients who reached 6 months of follow-up (M6).

RESULTS

We included 1584 PLWH [213 TN (13%) and 1371 TE (87%)]. The median (IQR) follow-up was 16 (7-21) months, with 81% and 53% of PLWH reaching M6 and M12, respectively. By OT, mITT and ITT, HIV-RNA <50 copies/mL was 77%, 70% and 62% at M6 and 92%, 77% and 63% at M12 for TN PLWH and 94%, 89% and 83% at M6 and 93%, 85% and 78% at M12 for TE PLWH, respectively. In PLWH carrying an M184V/I substitution, OT RNA <50 copies/mL was 89.5% at M6. The median CD4 cell count increased from 329 to 511/μL in TN PLWH and from 630 to 683/μL in TE PLWH at M6. Of the total, 1148 (88%) PLWH continued on BIC/FTC/TAF at M6. The most frequent known reason for discontinuation was toxicity [42 (69%) cases]; only 7 cases were considered virological failures (0.6% of the total OT cohort at M6), with no emerging resistance substitutions.

CONCLUSIONS

In real life, BIC/FTC/TAF showed high rates of virological suppression and also in PLWH carrying lamivudine/emtricitabine resistance substitutions. The tolerability and safety of BIC/FTC/TAF were good, with high persistence observed for patients on this regimen at M6.

High-level resistance to bictegravir and cabotegravir in subtype A- and D-infected HIV-1 patients failing raltegravir with multiple resistance mutations

OBJECTIVES

The second-generation integrase strand transfer inhibitor (INSTI) bictegravir is becoming accessible in low- and middle-income countries (LMICs), and another INSTI, cabotegravir, has recently been approved as a long-acting injectable. Data on bictegravir and cabotegravir susceptibility in raltegravir-experienced HIV-1 subtype A- and D-infected patients carrying drug resistance mutations (DRMs) remain very scarce in LMICs.

PATIENTS AND METHODS

HIV-1 integrase (IN)-recombinant viruses from eight patients failing raltegravir-based third-line therapy in Uganda were genotypically and phenotypically tested for susceptibility to bictegravir and cabotegravir. Ability of these viruses to integrate into human genomes was assessed in MT-4 cells.

RESULTS

HIV-1 IN-recombinant viruses harbouring single primary mutations (N155H or Y143R/S) or in combination with secondary INSTI mutations (T97A, M50I, L74IM, E157Q, G163R or V151I) were susceptible to both bictegravir and cabotegravir. However, combinations of primary INSTI-resistance mutations such as E138A/G140A/G163R/Q148R or E138K/G140A/S147G/Q148K led to decreased susceptibility to both cabotegravir (fold change in EC50 values from 429 to 1000×) and bictegravir (60 to 100×), exhibiting a high degree of cross-resistance. However, these same IN-recombinant viruses showed impaired integration capacity (14% to 48%) relative to the WT HIV-1 NL4-3 strain in the absence of drug.

CONCLUSIONS

Though not currently widely accessible in most LMICs, bictegravir and cabotegravir offer a valid alternative to HIV-infected individuals harbouring subtype A and D HIV-1 variants with reduced susceptibility to first-generation INSTIs but previous exposure to raltegravir may reduce efficacy, more so with cabotegravir.

Real-world efficacy and safety of switching to bictegravir/emtricitabine/tenofovir alafenamide in older people living with HIV

Approximately 50% of people living with HIV (PLWH) in the United States are ≥50 years old. Clinical trials of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) demonstrated potent efficacy and favorable safety in older PLWH; however, real-world data would be useful to validate these results.Retrospective cohort study.We evaluated records from PLWH aged ≥50 years at the Orlando Immunology Center who were switched to B/F/TAF between February 2018 and August 2019. Eligible patients had baseline HIV-1 RNA <50 copies/mL and 48 weeks of follow-up data. The primary endpoint was maintenance of HIV-1 RNA <50 copies/mL at Week 48. The impact of switching to B/F/TAF on drug-drug interactions (DDIs) and safety parameters were also assessed.Three-hundred and fifty patients met inclusion criteria, median age was 57 years, 20% were women, and 43% were non-White. Fifty-five percent of patients switched from integrase inhibitor-based regimens; the most common reason for switch was simplification. At Week 48, 330 (94%) patients maintained an HIV-1 RNA <50 copies/mL and 20 (6%) had an HIV-1 RNA between 50 and 400 copies/mL. One-hundred and forty potential DDIs were identified in 121 (35%) patients taking a boosting agent or rilpivirine at baseline that were resolved after switching to B/F/TAF. Treatment-related adverse events occurred in 51 (15%) patients (all Grade 1-2) and led to 8 discontinuations.In this real-world cohort, switching to B/F/TAF was associated with maintenance of virologic control, and avoidance of DDIs in a large proportion of patients. These data support use of B/F/TAF as a treatment option in older PLWH.

Prevalence of M184V and K65R in proviral DNA from PBMCs in HIV-infected youths with lamivudine/emtricitabine exposure

Objectives

We analysed the prevalence of M184V/I and/or K65R/E/N mutations archived in proviral DNA (pDNA) in youths with perinatal HIV, virological control and who previously carried these resistance mutations in historic plasma samples.

Methods

We included vertically HIV-infected youths/young adults aged ≥10 years in the Madrid Cohort of HIV-1 Infected Children and Adolescents, exposed to lamivudine and/or emtricitabine, with M184V/I and/or K65R/E/N in historic plasma samples, on antiretroviral therapy (ART), virologically suppressed (HIV-1 RNA <50 copies/mL), and with available PBMCs in the Spanish HIV BioBank. Genomic DNA was extracted from PBMCs and HIV-1 RT gene was amplified and sequenced for resistance testing by Stanford HIV Resistance tool.

Results

Among the 225 patients under follow-up in the study cohort, 13 (5.8%) met selection criteria, and RT sequences were recovered in 12 (92.3%) of them. All but one were Spaniards, carrying subtype B, with a median age at PBMCs sampling of 21.3 years (IQR: 15.6–23.1) with 4 years (IQR 2.1–6.5) of suppressed viral load (VL). Nine (75%) youths did not present M184V/I in pDNA after at least 1 year of viral suppression. In December 2019, the remaining three subjects carrying M184V/I in pDNA maintained suppressed viraemia, and two still used emtricitabine in ART.

Conclusions

The prevalence of resistance mutations to lamivudine and emtricitabine in pDNA in a cohort of youths perinatally infected with HIV who remain with undetectable VL, previously lamivudine and/or emtricitabine experienced, was infrequent. Our results indicate that ART including lamivudine or emtricitabine may also be safe and successful in youths with perinatal HIV with previous experience of and resistances to these drugs detected in plasma.

M184V/I does not impact the efficacy of abacavir/lamivudine/dolutegravir use as switch therapy in virologically suppressed patients

BACKGROUND

M184V/I NRTI resistance mutations can be selected by either lamivudine/emtricitabine or abacavir. There are controversies about the use of abacavir/lamivudine/dolutegravir combinations in HIV-1-infected treatment-experienced patients with a fully suppressed HIV viral load (VL) and harbouring M184V/I.

OBJECTIVES

We assessed the efficacy of abacavir/lamivudine/dolutegravir when used in HIV-infected pretreated patients with an undetectable VL who previously harboured M184V/I as a unique NRTI resistance mutation in a genotypic resistance test and had no resistance to integrase inhibitors.

PATIENTS AND METHODS

A total of 154 patients with a fully suppressed HIV-1 plasma VL (<50 copies/mL) treated with tenofovir disoproxil fumarate/emtricitabine/boosted PI or abacavir/lamivudine/boosted PI who switched to an abacavir/lamivudine/dolutegravir regimen and had M184V/I as a unique NRTI resistance mutation in their therapeutic history were retrospectively analysed up to 12 months after the switch to abacavir/lamivudine/dolutegravir. Assessment of residual viraemia was performed at Months 1, 3, 6 and 12. Plasma VL with undetectable HIV-1 RNA corresponded to an absence of residual viraemia.

RESULTS

During the 12 months of follow-up, three patients had a blip of VL (53, 62 and 106 copies/mL) at Month 3 followed by a subsequent VL <50 copies/mL. No patient harboured a virological failure during the follow-up. Moreover, there was no change in residual viraemia during the follow-up.

CONCLUSIONS

M184V/I as a unique NRTI resistance mutation, regardless of possible selection by regimens containing lamivudine/emtricitabine or abacavir, does not affect the virological response of well-controlled patients who switched to abacavir/lamivudine/dolutegravir for at least 12 months.

Case Report: Emergent Resistance in a Treatment-Naive Person With Human Immunodeficiency Virus Under Bictegravir-Based Therapy

Few instances of treatment-emergent resistance to bictegravir have been reported in the literature. We describe a case of treatment-emergent resistance to bictegravir in a person recently diagnosed with human immunodeficiency virus who developed M184V and R263K mutations while on therapy.

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.

Switching to Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) From Dolutegravir (DTG)+F/TAF or DTG+F/Tenofovir Disoproxil Fumarate (TDF) in the Presence of Pre-existing NRTI Resistance

BACKGROUND

Study 4030 was a phase 3, randomized, double-blinded study of 565 HIV-1 RNA-suppressed participants switching to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) or dolutegravir (DTG)+F/TAF. Nucleoside reverse transcriptase inhibitor (NRTI), non-NRTI, and protease inhibitor resistance (-R) was allowed, but integrase strand transfer inhibitor-R was excluded. Here, we describe the detailed resistance analysis.

METHODS

Historical plasma HIV-1 RNA genotypes and baseline proviral DNA genotypes were analyzed. Documented or investigator-suspected NRTI-R was grouped for stratification into 3 categories of level of resistance. Viral blips were assessed through week 48. Virologic failures had genotypic and phenotypic resistance analyses at week 48, confirmed failure, or last visit, if HIV-1 RNA did not resuppress to <50 copies/mL while on study drug.

RESULTS

In total, 83% (470/565) of participants had baseline genotypic data available with NRTI-R detected in 24% (138/565), including 5% (30/565) with K65R/E/N or ≥3 thymidine analog mutations and 19% (108/565) with other NRTI-R mutations. M184V/I was present in 14% (81/565). Pre-existing integrase strand transfer inhibitor-R mutations were found in 4% (20/565) of participants. Primary non-NRTI-R and protease inhibitor-R mutations were present in 21% (118/565) and 7% (38/565) of participants. High rates of viral suppression were maintained in all groups through week 48; blips were observed in only 15 participants (2.7%). Three participants met criteria for resistance analysis (all in DTG+F/TAF arm); none developed treatment-emergent resistance to study drugs.

CONCLUSIONS

Participants with baseline NRTI resistance, much of which was previously undocumented, maintained suppression 48 weeks after switching to B/F/TAF or DTG+F/TAF triple therapy. Blips and virologic failure were uncommon using either regimen, with no treatment-emergent resistance.

Bictegravir/Emtricitabine/Tenofovir Alafenamide in Virologically Suppressed People with HIV Aged ≥ 65 Years: Week 48 Results of a Phase 3b, Open-Label Trial

Introduction

We report the 48-week results of an ongoing study to assess the efficacy and safety of switching older people with HIV to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF).

Methods

This was a 96-week, phase 3b, open-label, single-arm study (GS-US-380-4449; NCT03405935). Virologically suppressed individuals aged ≥ 65 years receiving elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide or a tenofovir disoproxil fumarate-based regimen were switched to B/F/TAF. Primary endpoint was the percentage of participants with HIV-1 RNA < 50 copies/ml at week 24.

Results

Eighty-six participants (median age 69 [range 65–80] years; 87% male; 95% white) were enrolled and treated in five European countries. Rates of virologic suppression were 97.7% at week 24 and 90.7% at week 48; none had HIV-1 RNA ≥ 50 copies/ml, and 100% had virologic suppression by missing = excluded analysis at both time points. No treatment-emergent resistance was observed. There were no grade 3–4 study drug-related adverse events (AEs) or study drug-related serious AEs or deaths. Three AEs led to premature discontinuation; one (moderate abdominal discomfort) was attributed to the study drug by the investigator. At week 48, median changes from baseline in weight and estimated glomerular filtration rate were + 0.1 kg (interquartile range [IQR] − 1.0, 2.3) and − 6.0 ml/min (IQR − 10.2, 0.0), respectively. There were no clinically relevant changes from baseline to week 48 in fasting lipid parameters. Treatment satisfaction improved, and health-related quality of life was maintained from baseline through week 48. Median adherence to the study drug was 98.6% (IQR 96.0, 100).

Conclusions

Switching to B/F/TAF was effective and well tolerated through 48 weeks in virologically suppressed adults aged ≥ 65 years.

Trial Registration

ClinicalTrials.gov identifier, NCT03405935.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00419-5.

Antiretroviral Drug Treatment of Individuals that Used Preexposure Prophylaxis (PrEP) Before Diagnosis

Purpose of review

The antiretroviral drugs, tenofovir and emtricitabine used as preexposure prophylaxis (PrEP), are also used in treatment of HIV. Drug resistance due to PrEP can therefore jeopardize future treatment options. This review discusses treatment of individuals that used PrEP in whom viral mutations against tenofovir (K65R) or emtricitabine (M184I/V) are found.

Recent findings

Although no studies systematically investigated the optimal treatment of individuals who used PrEP before diagnosis, there is anecdotal evidence that HIV including the K65R and/or M184I/V can be successfully treated using recommended first-line regimens.

Summary

Drug resistance can be ascribed to use of PrEP while having an unrecognized acute HIV infection, partial adherence to PrEP, and transmission of HIV resistant to PrEP drugs. First-line antiretroviral drug treatment in individuals who used PrEP before diagnosis must be optimized based on genotypic resistance test results. Individuals in whom M184I/V and/or K65R is detected can be treated with dolutegravir-based, bictegravir-based, or darunavir-based regimens plus tenofovir plus lamivudine or emtricitabine. Dual therapy using dolutegravir plus lamivudine is not recommended for induction therapy in individuals with viral mutations against the drugs used as PrEP. There is an urgent need to confirm the anecdotal evidence for successful treatment using first-line regimens.

Simulating HIV Breakthrough and Resistance Development During Variable Adherence to Antiretroviral Treatment

BACKGROUND

Barriers to lifelong HIV-1 suppression by antiretrovirals include poor adherence and drug resistance; regimens with higher tolerance to missed doses (forgiveness) would be beneficial to patients. To model short-term nonadherence, in vitro experiments monitoring viral breakthrough (VB) and resistance development were conducted.

METHODS

HIV breakthrough experiments simulated drug exposures at full adherence or suboptimal adherence to bictegravir+emtricitabine+tenofovir alafenamide (BIC+FTC+TAF) or dolutegravir + lamivudine (DTG+3TC). MT-2 cells were infected with wild-type or low frequency M184V HIV-1, exposed to drug combinations, monitored for VB, and rebound virus was deep sequenced. Drug concentrations were determined using human plasma-free adjusted clinical trough concentrations (Cmin), at simulated Cmin after missing 1 to 3 consecutive doses (Cmin - 1 or Cmin - 2, and Cmin - 3) based on drug or active metabolite half-lives.

RESULTS

Cultures infected with wild-type or low frequency M184V HIV-1 showed no VB with BIC+FTC+TAF at drug concentrations corresponding to Cmin, Cmin - 1, or Cmin - 2 but breakthrough did occur in 26 of 36 cultures at Cmin - 3, where the M184V variant emerged in one culture. Experiments using DTG + 3TC prevented most breakthrough at Cmin concentrations (9/60 had breakthrough) but showed more breakthroughs as drug concentrations decreased (up to 36/36) and variants associated with resistance to both drugs emerged in some cases.

CONCLUSIONS

These in vitro VB results suggest that the high potency, long half-lives, and antiviral synergy provided by the BIC/FTC/TAF triple therapy regimen may protect from viral rebound and resistance development after short-term lapses in drug adherence.

Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2020 Recommendations of the International Antiviral Society-USA Panel

Importance

Data on the use of antiretroviral drugs, including new drugs and formulations, for the treatment and prevention of HIV infection continue to guide optimal practices.

Objective

To evaluate new data and incorporate them into current recommendations for initiating HIV therapy, monitoring individuals starting on therapy, changing regimens, preventing HIV infection for those at risk, and special considerations for older people with HIV.

Evidence Review

New evidence was collected since the previous International Antiviral (formerly AIDS) Society-USA recommendations in 2018, including data published or presented at peer-reviewed scientific conferences through August 22, 2020. A volunteer panel of 15 experts in HIV research and patient care considered these data and updated previous recommendations.

Findings

From 5316 citations about antiretroviral drugs identified, 549 were included to form the evidence basis for these recommendations. Antiretroviral therapy is recommended as soon as possible for all individuals with HIV who have detectable viremia. Most patients can start with a 3-drug regimen or now a 2-drug regimen, which includes an integrase strand transfer inhibitor. Effective options are available for patients who may be pregnant, those who have specific clinical conditions, such as kidney, liver, or cardiovascular disease, those who have opportunistic diseases, or those who have health care access issues. Recommended for the first time, a long-acting antiretroviral regimen injected once every 4 weeks for treatment or every 8 weeks pending approval by regulatory bodies and availability. For individuals at risk for HIV, preexposure prophylaxis with an oral regimen is recommended or, pending approval by regulatory bodies and availability, with a long-acting injection given every 8 weeks. Monitoring before and during therapy for effectiveness and safety is recommended. Switching therapy for virological failure is relatively rare at this time, and the recommendations for switching therapies for convenience and for other reasons are included. With the survival benefits provided by therapy, recommendations are made for older individuals with HIV. The current coronavirus disease 2019 pandemic poses particular challenges for HIV research, care, and efforts to end the HIV epidemic.

Conclusion and Relevance

Advances in HIV prevention and management with antiretroviral drugs continue to improve clinical care and outcomes among individuals at risk for and with HIV.

Marked decrease in acquired resistance to antiretrovirals in latest years in Italy

OBJECTIVES

The aim of this study was to evaluate acquired drug resistance in Italy in the 2009-2018 period.

METHODS

We analysed 3094 patients from the Italian ARCA database who had failed antiretroviral treatment and who had received a genotypic test after 6 months of treatment. Drug resistance mutations were identified using International AIDS Society (IAS)-USA tables and the Stanford HIVdb algorithm. The global burden of acquired resistance was calculated among all subjects with antiretroviral failure. Time trends and correlates of resistance were analysed using standard statistical tests.

RESULTS

Patients of non-European origin and non-B subtypes increased significantly from 11.5% (103/896) to 19.2% (33/172) and from 13.1% (141/1079) to 23.8% (53/223), respectively, over time. Overall, 14.5% (448/3094), 12.1% (374/3094) and 37.8% (1169/3094) of patients failed first, second and later lines, respectively. According to both IAS and HIVdb, in the study period resistance to any class, nucleoside reverse inhibitor, non-nucleoside reverse inhibitor, and protease inhibitors (PIs) declined significantly. Integrase strand transfer inhibitor (INSTI) resistance declined significantly from 31% (36/116) to 20.8% (41/197) according to HIVdb but not to IAS. Divergent data were highlighted regarding the proportion of non-European patients carrying any, PI and INSTI resistance using IAS tables compared with the Stanford HIVdb algorithm, as the former failed to detect a decrease in resistance while the latter indicates a reduction of 1.6-, 5- and 1.8-fold resistance for such drug classes. In the multivariate analysis, the risk of resistance increased in patients with a larger number of treatment lines and higher viraemia and decreased in those starting therapy in the last biennium of the study.

DISCUSSION

A marked reduction in drug resistance was observed over 10 years, compatible with higher genetic barrier and potency of new antiretrovirals. Nonetheless, concerns remain for subjects with non-B subtypes when using mutation lists instead of interpretation systems because of the extensive polymorphism of the protease region.

Failure to bictegravir and development of resistance mutations in an antiretroviral-experienced patient

We present here one of the first cases of virological failure during treatment with bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). On March 2019, an antiretroviral-experienced HIV-infected patient was admitted to hospital because of cerebral toxoplasmosis. After undergoing treatment with sulfadiazine-pyrimethamine for two weeks, the patient initiated a BIC/FTC/TAF treatment, with 6.01 HIV RNA Log copies/mL, and 37 CD4 cells/μL. After two months under antiretroviral therapy (ART), acute neurologic deterioration with epilepsy, right hemiparesis and dysphagia occurred, leading to nasogastric nutrition and treatment. After several weeks, virological failure was confirmed with 4.01 HIV RNA Log copies/mL and R263K and M184V resistance mutations were detected.

Clinical Outcomes Following the Use of Archived Proviral HIV-1 DNA Genotype to Guide Antiretroviral Therapy Adjustment

Background

Evidence regarding the safety of using proviral HIV-1 DNA genotype (DNA GT) to guide antiretroviral therapy (ART) is limited. We hypothesized that HIV RNA would not increase following ART adjustment guided by DNA GT in a university HIV clinic.

Methods

Data were obtained from electronic medical records of adult persons living with HIV-1 (PWH) who underwent DNA GT testing and changed ART between October 2014 and November 2017. Logistic regression was used to evaluate the effect of ART switch on HIV RNA over time.

Results

Eighty-three PWH had DNA GT performed, 66 (80%) switched ART, and 59 had postswitch follow-up. Data were analyzed pre-/postswitch for these 59 PWH (median age, 54 years; 71% LWH ≥10 years; 46% ≥2 previous regimens; 36% recent low-level viremia; 34% unknown medication history). On DNA GT, 58% had ≥1-class ART resistance, 34% ≥2-class, and 10% 3-class. Median follow-up (range) was 337 (34–647) days. There was no change in probability of HIV RNA ≥50 copies/mL over time (P > .05). At baseline, 76% had HIV RNA <50 vs 88% at last postswitch follow-up (P = .092). Protease inhibitor use decreased from 58% to 24% (P < .001). Average daily pills and dosing frequency decreased from 3.48 to 2.05 (P < .001) and 1.39 to 1.09 (P < .001), respectively; ART cost did not change.

Conclusions

DNA GT facilitated changes in ART in a treatment-experienced population without increases in HIV RNA. Decreased pill burden occurred without increased ART cost. Further studies to identify optimal use of DNA GT are needed.

5′-Chloro-5′-deoxy-2′,3′-O-isopropylidene-6-fluoro nebularine

In this paper, we report on the synthesis and spectroscopic characterization of the novel nucleoside 5′-chloro-5′-deoxy-2′,3′-O-isopropylidene-6-fluoro nebularine, obtained as a side product during the second step of the synthesis of 5′-fluoro-5′-deoxy-5-aminoimidazole-4-carboxamide-β-d-riboside (5′-F-AICAR), a non-phosphorylable analogue of 5-aminoimidazole-4-carboxamide-β-d-riboside (AICAR).