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

Clinical considerations when switching antiretroviral therapy

INTRODUCTION

Antiretroviral therapy (ART) can be personalized through simple formulations with high resistance barriers, favorable safety profiles, and novel administration routes. Switching treatments has become a key clinical strategy for addressing drug toxicity and interactions and enhancing adherence and convenience. This strategy aims to improve the quality of life and long-term efficacy, even in challenging cases like people living with HIV (PLWH) with multiple comorbidities, prior virological failure, and drug resistance.

AREAS COVERED

The authors reviewed clinical trials and cohort studies providing evidence of benefits and risks of current antiretroviral (ARV) drugs as switching options for PLWH in various scenarios. The literature search included clinical trials, meta-analyses, observational studies, and review articles in English published after 2000, and current HIV treatment guidelines in English and Spanish as of February 2024.

EXPERT OPINION

New ARV drugs offer advantages in efficacy and safety over previous options but may also have adverse effects. Second-generation integrase inhibitors and tenofovir alafenamide show benefits as switching options in various scenarios, though more research is needed on potential weight gain and metabolic issues. Injectable long-acting ART is promising for switching strategies, but finding the optimal combination of new drugs remains challenging.

Switching Human Immunodeficiency Virus Therapy: Basic Principles and Options

The number of options for effective antiretroviral therapy (ART) is steadily increasing. Although older regimens may achieve the goal of virologic suppression, newer options can offer advantages in safety, tolerability, and convenience. In this article, we offer guiding principles for switching ART, highlighting reasons to pursue a switch and key factors to consider when selecting a new regimen.

Multicentre service evaluation of injectable cabotegravir and rilpivirine delivery and outcomes across 12 UK clinics (SHARE LAI-net)

INTRODUCTION

Long-acting injectable cabotegravir + rilpivirine (CAB + RPV LAI) was approved for use in virally suppressed adults in the England and Wales national health service in November 2021. We describe a service evaluation of delivery processes and outcomes in 12 clinics.

METHODS

Centres populated a database using information from local policies and clinical records. Services were asked to describe approval processes, clinic pathways, and adherence to national guidelines. Additional data were collected on reasons for regimen choice, treatment discontinuations, and management of viraemia.

RESULTS

In total, 518 adults from 12 clinics were approved for CAB + RPV LAI between February 2022 and December 2023. Of the 518 people approved for CAB + RPV LAI, 423 received at least one injection. Median duration on CAB + RPV was 7.5 months (interquartile range 3.7-11.3). In total, 97% of injections were administered within the ±7-day window. Virological failure occurred in 0.7%, and 6% discontinued CAB + RPV.

CONCLUSION

In this large UK-based cohort, robust approval processes and clinic protocols facilitated on-time injections and low rates of both discontinuation and virological failure.

Effectiveness, safety and discontinuation rates of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) in people with HIV using real-world data: a systematic review and meta-analysis

BACKGROUND

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

OBJECTIVES

To assess the effectiveness and safety of BIC/FTC/TAF in treatment-naïve (TN) and treatment-experienced (TE) people with HIV using available real-world cohort studies.

METHODS

Systematic review and meta-analysis of publications and communications identified via Boolean search in Medline, PubMed and Embase, and conference abstracts reporting retrospective real-world use of BIC/FTC/TAF, published until 31 January 2024. The primary endpoint was the proportion of TN and TE people with HIV with viral load (VL) < 50 copies/mL at 48 weeks while on treatment.

RESULTS

Of the 38 identified publications and conference abstracts, for the present analysis we included 12 publications (comprising 792 TN and 6732 TE individuals). For the three publications including 507 TN participants reporting the primary outcome, VL suppression was 97% [95% confidence intervals (CI): 89-100]. For the nine publications including 4946 TE participants reporting the primary outcome, VL suppression was 95% (95% CI: 94-96), with suppression >93% in all studies. Total discontinuations at 48 weeks in TE individuals were 3% (95% CI: 2-5), 1% (95% CI: 0-2) due to side effects. A total of four publications with 151 TE individuals with previous presence of M184V substitution were identified, reporting a suppression rate at 48 weeks of 95% (95% CI: 88-100).

CONCLUSIONS

Real-world studies demonstrate low discontinuation rates and high rates of virologic suppression in individuals treated with BIC/FTC/TAF, both TN and TE with and without previous detection of M184V substitution.

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 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.

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.

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.

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.

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.

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.

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.

Pharmacokinetic interactions of modern antiretroviral therapy

Drug--drug interactions (DDIs) have been a clinical challenge in HIV medicine for over two decades. The newer antiretroviral drugs (ARTs) have significantly fewer DDIs than protease inhibitors and boosted integrase inhibitors (INSTIs). The lower propensity of such newer antiretrovirals (e.g. unboosted integrase inhibitors; doravirine) to cause DDIs, has been largely offset by the ageing cohort of patients with multiple comorbidities, who are taking multiple chronic medicines. Furthermore, the introduction of newly marketed drugs into clinical practice needs to be closely monitored, as the new drugs may be perpetrators of DDIs, leading to a potential change in the efficacy or toxicity of the coadministered antiretrovirals.

Combined cART including Tenofovir Disoproxil, Emtricitabine, and Dolutegravir has potent therapeutic effects in HIV-1 infected humanized mice

HIV-1 reservoirs persist in the presence of combined antiretroviral therapy (cART). However, cART has transformed HIV-1 infection into a chronic disease marked by control of HIV-1 viral load and mortality reduction. Major challenges remain, including viral resistance upon termination of cART and persistence and identification of tissue distribution of HIV-1 reservoirs. Thus, appropriate animal models that best mimic HIV-1 pathogenesis are important, and the current study complements our previously published validation of the CD34+ hematopoietic humanized mouse model for this purpose. Here we analyze viral suppression using the recently developed combination of antiretrovirals that include Tenofovir Disoproxil (TDF), Emtricitabine (FTC), and Dolutegravir (DTG), a choice based on recent clinical outcomes showing its improved antiretroviral potency, CD4+ T cell preservation, tolerability, and prevention of viral drug resistance compared to that of previous regimens. We used quantitative Airyscan-based super resolution confocal microscopy of selected mouse tissues. Our data allowed us to identify specific solid tissue reservoirs of human T cells expressing the HIV-1 core protein p24. In particular, lymph node, brain, spleen, and liver were visualized as reservoirs for residual infected cells. Marked reduction of viral replication was evident. Considering that detection and visualization of cryptic sites of HIV-1 infection in tissues are clearly crucial steps towards HIV-1 eradication, appropriate animal models with pseudo-human immune systems are needed. In fact, current studies with humans and non-human primates have limited sample availability at multiple stages of infection and cannot easily analyze the effects of differently administered combined antiretroviral treatments on multiple tissues. That is easier to manage when working with humanized mouse models, although we realize the limitations due to low human cell recovery and thus the number of cells available for thorough and comprehensive analyses. Nonetheless, our data further confirm that the CD34+ humanized mouse model is a potentially useful pre-clinical model to study and improve current anti-HIV-1 therapies.

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.