Predictors of virological failure in HIV-1-infected patients switching to dolutegravir maintenance monotherapy

Comparison of the design and methodology of Phase 3 clinical trials of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) and dolutegravir-based dual therapy (DTG) in HIV: a systematic review of the literature

INTRODUCTION

Current recommended antiretroviral regimens include a combination of two (dual; DT) or three (triple; TT) antiretroviral drugs. This study aims to determine whether the quality of evidence from clinical trials of dolutegravir (dolutegravir/lamivudine [DTG/3TC] or dolutegravir/rilpivirine [DTG/RPV]) is methodologically comparable to that of clinical trials conducted with bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF).

AREAS COVERED

A systematic review of the medical literature was carried out in PubMed without date or language restrictions, following the PRISMA guidelines. All aspects of the methodological design of phase 3 randomized clinical trials (RCTs) of DT and TT, evaluated by the European Medicines Agency (registration trials), were reviewed. The quality of clinical trials was assessed using the Jadad scale.

EXPERT OPINION

The search identified 5, 3 and 2 phase 3 RCTs with BIC/FTC/TAF, DTG/3TC and DTG/RPV, respectively, that met the inclusion criteria. The designs would not be comparable due to differences in pre-randomization losses, blinding, patient recruitment, as well as differences in methodological quality, with the average score of the RCTs conducted with BIC/FTC/TAF, DTG/3TC and DTG/RPV being 4.2 (high quality), 3.0 (medium quality) and 3.0 (medium quality), respectively. Due to methodological differences between the BIC/FTC/TAF, DTG/3TC and DTG/RPV RCTs, the results of these are not comparable.

Pre-treatment HIV-1 drug resistance in antiretroviral therapy-naive adults in Eastern Africa: a systematic review and meta-analysis

BACKGROUND

Pre-treatment HIV drug resistance (PDR) may result in increased risk of virological failure and acquisition of new resistance mutations. With recently increasing ART coverage and periodic modifications of the guidelines for HIV treatment, there is a need for an updated systematic review to assess the levels of the PDR among adults newly initiating ART in Eastern Africa.

METHODS

We conducted a systematic search for studies published between 1 January 2017 and 30 April 2022 in the MEDLINE Complete and CINAHL Complete, searched simultaneously using EBSCOhost, and Web of Science. To determine the overall PDR prevalence estimates, we extracted data from eligible articles and analysed prevalence estimates using Stata 14.2.

RESULTS

A total of 22 eligible observation studies were selected. The studies included a total of 5852 ART-naive people living with HIV. The overall pooled prevalence of PDR was 10.0% (95% CI: 7.9%-12.0%, I2 = 88.9%) and 9.4% (95% CI: 7.0%-11.9%, I2 = 90.4%) for NNRTIs, 2.6% (95% CI: 1.8%-3.4%, I2 = 69.2%) for NRTIs and 0.7% (95% CI: 0.3%-1.2%, I2 = 29.0%) for PIs. No major integrase strand transfer inhibitors (INSTI)-related mutations were identified.

CONCLUSIONS

We observed a moderate overall PDR prevalence among new ART initiators in this study. PDR to NNRTIs is more prevalent, underscoring the importance of the current WHO recommendation for replacement of NNRTIs by INSTIs. PDR to NRTIs was low but notable, which warrants continuous surveillance of pre-existing resistance to the dolutegravir co-administered NRTI in Eastern Africa.

Dolutegravir monotherapy as maintenance strategy: a meta-analysis of individual participant data from randomized controlled trials

Background

Dolutegravir monotherapy (DTG-m) results in virological failure (VF) in some people with human immunodeficiency virus (PWH). We sought to identify the independent factors associated with the risk of VF and to explore the effect size heterogeneity between subgroups of PWH enrolled in DTG-m trials.

Methods

We searched for randomized clinical trials (RCTs) evaluating DTG-m versus combined antiretroviral therapy (cART) among PWH virologically controlled for at least 6 months on cART. We performed an individual participant data meta-analysis of VF risk factors and quantified their explained heterogeneity in random-effect models. Definition of VF was a confirmed plasma human immunodeficiency virus (HIV)-1 ribonucleic acid (RNA) >50 copies/mL by week 48.

Results

Among 416 PWH from 4 RCTs, DTG-m significantly increased the risk of VF (16 of 227 [7%] versus 0 of 189 for cART; risk difference 7%; 95% confidence interval [CI], 1%–2%; P = .02; I² = 51%). Among 272 participants exposed to DTG-m, VF were more likely in participants with the following: first cART initiated ≥90 days from HIV acute infection (adjusted hazard ratio [aHR], 5.16; 95% 95% CI, 1.60–16.65), CD4 T cells nadir <350/mm³ (aHR, 12.10; 95% CI, 3.92–37.40), HIV RNA signal at baseline (aHR, 4.84; 95% CI, 3.68–6.38), and HIV-deoxyribonucleic acid (DNA) copy number at baseline ≥2.7 log/10⁶ peripheral blood mononuclear cells (aHR, 3.81; 95% CI, 1.99–7.30). Among these independent risk factors, the largest effect size heterogeneity was found between HIV DNA subgroups (I² = 80.2%; P for interaction = .02).

Conclusions

Our study supports the importance of a large viral reservoir size for explaining DTG-m simplification strategy failure. Further studies are needed to link size and genetic diversity of the HIV-1 reservoir.

External quality assessment of HIV-1 DNA quantification assays used in the clinical setting in Italy

Total cell-associated HIV-1 DNA is a surrogate marker of the HIV-1 reservoir, however, certified systems for its quantification are not available. The Italian HIV DNA Network was launched to validate HIV-1 DNA quantification methods in use at University and Hospital labs. A quality control panel including HIV-1 DNA standards, reconstructed blood samples (RBSs) and DNA from different HIV-1 subtypes was blindly tested by 12 participating labs by quantitative real-time PCR (n = 6), droplet digital PCR (n = 3) or both (n = 3). The median 95% hit rate was 4.6 (3.7–5.5) copies per test and linearity in the tested range was excellent (R2 = 1.000 [1.000–1.000]). The median values obtained across labs were 3,370 (2,287–4,245), 445 (299–498), 59 (40–81) and 7 (6–11) HIV-1 DNA copies, for the 3,584, 448, 56 and 7-copy standards, respectively. With RBSs, measured values were within twofold with respect to the median in two thirds of cases. HIV-1 subtypes were missed (CRF01_AE by 3 labs) or underestimated by > 1 log (subtypes A, C, D, F by one lab; CRF01_AE by one lab; CRF02_AG by one lab). The overall performance was excellent with HIV-1 DNA standards, however detection of different HIV-1 subtypes must be improved.

Quantification of Total HIV DNA as a Marker to Measure Viral Reservoir: Methods and Potential Implications for Clinical Practice

The focus of this review is to examine the importance of quantifying total HIV DNA to target the HIV reservoir and the clinical implications and challenges involved in its future application in clinical practice. Despite intrinsic limitations, the quantification of total HIV DNA is currently the most widely used marker for exploring the HIV reservoir. As it allows estimating all forms of HIV DNA in the infected cells, total HIV DNA load is the biomarker of the HIV reservoir that provides most of the insights into HIV pathogenesis. The clinical role of total HIV-DNA in both untreated and treated patients is extensively supported by important lines of evidence. Thus, predictive models that include total HIV DNA load together with other variables could constitute a prognostic tool for use in clinical practice. To date, however, this marker has been primarily used in experimental evaluations. The main challenge is technical. Although the implementation of droplet digital PCR could improve analytical performance over real-time PCR, the lack of standardization has made cross-comparisons of the data difficult. An effort by investigators to compare protocols is needed. Furthermore, the main effort now should be to involve the biomedical industry in the development of certified assays for in vitro diagnostics use.

Long-term follow-up of HIV-infected patients on dolutegravir monotherapy

BACKGROUND

In recent years, dolutegravir monotherapy has been explored as a drug-reduced regimen for HIV patients.

METHODS

This was a retrospective observational study, including patients virologically suppressed for ≥6 months, without previous virological failure (VF) under integrase inhibitors (INIs), who had been switched to dolutegravir monotherapy (50 mg/day). The primary aim was to report the proportion of VF at week 48 (W48) and week 96 (W96) of dolutegravir monotherapy. The evolution from baseline to W48 of residual viraemia on ultra-deep sequencing and HIV DNA was also evaluated.

RESULTS

Sixty-one patients were included. Prior to switching to dolutegravir monotherapy, they had a median (IQR) of 15.4 (6.5-19.9) years of antiretroviral exposure, 5.8 (3.2-10.3) years of viral suppression and 687 (461-848) CD4+ cells/mm3. They remained on dolutegravir monotherapy for a median (IQR) of 100 (29-148) weeks. Forty-two out of 61 patients (68.9%) reached W48 and 32 out of 61 patients (52.5%) reached W96. VF occurred in three patients, with the emergence of INI resistance. VF occurred before W24 and in patients pre-exposed to INIs. At W48, the probability of VF (Kaplan-Meier analysis) was 5.6% (95% CI = 1.8%-16.4%). The same result was obtained at W96. Detectable residual viraemia did not increase and median HIV DNA did not change significantly (2.4 log/106 cells at baseline and 2.3 log/106 cells at W48). Dolutegravir plasma concentration was above the IC90 in 41/41 samples, from 22 patients.

CONCLUSIONS

Long-term follow-up showed a low risk of VF under dolutegravir monotherapy, in a selected population of patients with previous long-term virological suppression and low HIV reservoir.

Integrase Strand Transfer Inhibitors Are Effective Anti-HIV Drugs

Integrase strand transfer inhibitors (INSTIs) are currently recommended for the first line treatment of human immunodeficiency virus type one (HIV-1) infection. The first-generation INSTIs are effective but can select for resistant viruses. Recent advances have led to several potent second-generation INSTIs that are effective against both wild-type (WT) HIV-1 integrase and many of the first-generation INSTI-resistant mutants. The emergence of resistance to these new second-generation INSTIs has been minimal, which has resulted in alternative treatment strategies for HIV-1 patients. Moreover, because of their high antiviral potencies and, in some cases, their bioavailability profiles, INSTIs will probably have prominent roles in pre-exposure prophylaxis (PrEP). Herein, we review the current state of the clinically relevant INSTIs and discuss the future outlook for this class of antiretrovirals.

Mechanistic Analysis of the Broad Antiretroviral Resistance Conferred by HIV-1 Envelope Glycoprotein Mutations

Although combination antiretroviral (ARV) therapy is highly effective in controlling the progression of HIV disease, drug resistance can be a major obstacle. Recent findings suggest that resistance can develop without ARV target gene mutations.

Despite the effectiveness of antiretroviral (ARV) therapy, virological failure can occur in some HIV-1-infected patients in the absence of mutations in drug target genes. We previously reported that, in vitro, the lab-adapted HIV-1 NL4-3 strain can acquire resistance to the integrase inhibitor dolutegravir (DTG) by acquiring mutations in the envelope glycoprotein (Env) that enhance viral cell-cell transmission. In this study, we investigated whether Env-mediated drug resistance extends to ARVs other than DTG and whether it occurs in other HIV-1 isolates. We demonstrate that Env mutations can reduce susceptibility to multiple classes of ARVs and also increase resistance to ARVs when coupled with target-gene mutations. We observe that the NL4-3 Env mutants display a more stable and closed Env conformation and lower rates of gp120 shedding than the WT virus. We also selected for Env mutations in clinically relevant HIV-1 isolates in the presence of ARVs. These Env mutants exhibit reduced susceptibility to DTG, with effects on replication and Env structure that are HIV-1 strain dependent. Finally, to examine a possible in vivo relevance of Env-mediated drug resistance, we performed single-genome sequencing of plasma-derived virus from five patients failing an integrase inhibitor-containing regimen. This analysis revealed the presence of several mutations in the highly conserved gp120-gp41 interface despite low frequency of resistance mutations in integrase. These results suggest that mutations in Env that enhance the ability of HIV-1 to spread via a cell-cell route may increase the opportunity for the virus to acquire high-level drug resistance mutations in ARV target genes.

A systematic review of the genetic mechanisms of dolutegravir resistance

Background

Characterizing the mutations selected by the integrase strand transfer inhibitor (INSTI) dolutegravir and their effects on susceptibility is essential for identifying viruses less likely to respond to dolutegravir therapy and for monitoring persons with virological failure (VF) on dolutegravir therapy.

Methods

We systematically reviewed dolutegravir resistance studies to identify mutations emerging under dolutegravir selection pressure, the effect of INSTI resistance mutations on in vitro dolutegravir susceptibility, and the virological efficacy of dolutegravir in antiretroviral-experienced persons.

Results and conclusions

We analysed 14 studies describing 84 in vitro passage experiments, 26 studies describing 63 persons developing VF plus INSTI resistance mutations on a dolutegravir-containing regimen, 41 studies describing dolutegravir susceptibility results, and 22 clinical trials and 16 cohort studies of dolutegravir-containing regimens. The most common INSTI resistance mutations in persons with VF on a dolutegravir-containing regimen were R263K, G118R, N155H and Q148H/R, with R263K and G118R predominating in previously INSTI-naive persons. R263K reduced dolutegravir susceptibility ∼2-fold. G118R generally reduced dolutegravir susceptibility >5-fold. The highest levels of reduced susceptibility occurred in viruses containing Q148 mutations in combination with G140 and/or E138 mutations. Dolutegravir two-drug regimens were highly effective for first-line therapy and for virologically suppressed persons provided dolutegravir’s companion drug was fully active. Dolutegravir three-drug regimens were highly effective for salvage therapy in INSTI-naive persons provided one or more of dolutegravir’s companion drugs was fully active. However, dolutegravir monotherapy in virologically suppressed persons and functional dolutegravir monotherapy in persons with active viral replication were associated with a non-trivial risk of VF plus INSTI resistance mutations.

Noninferiority of Simplified Dolutegravir Monotherapy Compared to Continued Combination Antiretroviral Therapy That Was Initiated During Primary Human Immunodeficiency Virus Infection: A Randomized, Controlled, Multisite, Open-label, Noninferiority Trial

BACKGROUND

Patients who start combination antiretroviral therapy (cART) during primary human immunodeficiency virus type 1 (HIV-1) infection show a smaller HIV-1 latent reservoir, less immune activation, and less viral diversity compared to patients who start cART during chronic infection. We conducted a pilot study to determine whether these properties would allow sustained virological suppression after simplification of cART to dolutegravir monotherapy.

METHODS

EARLY-SIMPLIFIED is a randomized, open-label, noninferiority trial. Patients who started cART <180 days after a documented primary HIV-1 infection and had an HIV-1 RNA <50 copies/mL plasma for at least 48 weeks were randomized (2:1) to monotherapy with dolutegravir 50 mg once daily or to continuation of cART. The primary efficacy endpoint was the proportion of patients with <50 HIV-1 RNA copies/mL on or before week 48; noninferiority margin 10%.

RESULTS

Of the 101 patients randomized, 68 were assigned to simplification to dolutegravir monotherapy and 33 to continuation of cART. At week 48 in the per-protocol population, 67/67 (100%) had virological response in the dolutegravir monotherapy group vs 32/32 (100%) in the cART group (difference, 0.00%; 95% confidence interval, -100%, 4.76%). This showed noninferiority of the dolutegravir monotherapy at the prespecified level.

CONCLUSION

In this pilot study consisting of patients who initiated cART during primary HIV-1 infection and had <50 HIV-1 RNA copies/mL for at least 48 weeks, monotherapy with once-daily dolutegravir was noninferior to cART. Our results suggest that future simplification studies should use a stratification according to time of HIV infection and start of first cART.

CLINICAL TRIALS REGISTRATION

NCT02551523.

Dolutegravir Monotherapy Versus Dolutegravir/Abacavir/Lamivudine for Virologically Suppressed People Living With Chronic Human Immunodeficiency Virus Infection: The Randomized Noninferiority MONotherapy of TiviCAY Trial

BACKGROUND

We investigated whether dolutegravir (DTG) monotherapy could be used to maintain virological suppression in people living with human immunodeficiency virus (HIV) on a successful dolutegravir-based triple therapy.

METHODS

MONCAY (MONotherapy of TiviCAY) was a 48-week, multicentric, randomized, open-label, 12% noninferiority margin trial. Patients with CD4 nadir >100/μL, plasma HIV-1 RNA <50 copies/mL for ≥12 months, and stable regimen with DTG/abacavir (ABC)/lamivudine (3TC) were 1:1 randomized to continue their regimen or to DTG monotherapy. The primary endpoint was the proportion of patients with HIV RNA <50 copies/mL at week 24 in intention-to-treat snapshot analysis. Virologic failure (VF) was defined as 2 consecutive HIV RNA >50 copies/mL within 2 weeks apart.

RESULTS

Seventy-eight patients were assigned to DTG monotherapy and 80 to continue DTG/ABC/3TC. By week 24, 2 patients in the DTG group experienced VF without resistance to the integrase strand transfer inhibitor (INSTI) class; 1 patient discontinued DTG/ABC/3TC due to an adverse event. The success rate at week 24 was 73/78 (93.6%) in the DTG arm and 77/80 (96.3%) in the DTG/ABC/3TC arm (difference, 2.7%; 95% confidence interval [CI], -5.0 to 10.8). During subsequent follow-up, 5 additional VFs occurred in the DTG arm (2 of which harbored emerging resistance mutation to INSTI). The cumulative incidence of VF at week 48 was 9.7% (95% CI, 2.8 to 16.6) in the DTG arm compared with 0% in the DTG/ABC/3TC arm (P = .005 by the log-rank test). The Data Safety Monitoring Board recommended to reintensify the DTG arm with standardized triple therapy.

CONCLUSIONS

Because the risk of VF with resistance increases over time, we recommend avoiding DTG monotherapy as a maintenance strategy among people living with chronic HIV infection.

CLINICAL TRIALS REGISTRATION

NCT02596334 and EudraCT 2015-002853-36.

Occurrence of the S230R integrase strand inhibitor mutation in a treatment-naïve individual case report

RATIONALE

Transmitted resistance to integrase strand inhibitors (INSTI) has been uncommon, but is slowly becoming more prevalent among those living with HIV. In an era with 2-drug regimens for antiretroviral therapy, transmitted resistance for INSTI is alarming.

PATIENT CONCERNS

A 28-year-old African American female was recently diagnosed with HIV during a 30-week prenatal visit.

DIAGNOSIS

HIV 4th generation test was positive as well as confirmation. Genotype was performed using next generation sequencing.

INTERVENTIONS

Patient was initially rapidly started on a dolutegravir based regimen and changed to a protease inhibitor regimen once her genotype reported an S230R mutation.

OUTCOMES

Patient became virally suppressed on antiretroviral therapy and delivered an HIV negative baby.

LESSONS

INSTI resistance testing should be done for treatment-naïve and INSTI-naïve persons, particularly when considering 2 drug INSTI based regimens.

Virological Outcome After Choice of Antiretroviral Regimen Guided by Proviral HIV-1 DNA Genotyping in a Real-Life Cohort of HIV-Infected Patients

Issues have been raised concerning clinical relevance of HIV-1 proviral DNA genotypic resistance test (DNA GRT). To assess impact of DNA GRT on choice of antiretroviral therapy (ART) and subsequent virological outcome, we retrospectively reviewed decision-making and viral load (VL) evolution following DNA GRT performed in our center between January 2012 and December 2017, except those prescribed within the framework of a clinical trial. A total of 304 DNA GRTs were included, 185 (62%) performed in a context of virological success. Only 34% of tests were followed by ART change, more frequently in situation of virological success (39% vs. 26%, p = 0.02). In this situation, ART change guided by DNA GRT led to VL >20 copies/mL after 6 months in 5% of cases. In multivariate analysis, higher HIV DNA quantification (p = 0.01) was associated with occurrence of viremia. A higher nadir of CD4 count (p = 0.04) and a longer time with VL <20 copies/mL (p = 0.04) were independently associated with a lower risk of viremia. In situation of low-level viremia, ART change guided by DNA GRT led to VL <20 copies/mL after 6 months in 52% of cases, while decision to maintain the same treatment led to VL <20 copies/mL in 74% of cases. In multivariate analysis, longer time with VL >20 copies/mL (p = 0.02) was associated with persistence of virological replication. In conclusion, in situation of virological success, use of DNA GRT in addition to analysis of historical RNA GRT to guide ART optimization appears safe. Its prescription framework in situation of low-level viremia deserves to be better defined.

Switching to dual antiretroviral regimens is associated with improvement or no changes in activation and inflammation markers in virologically suppressed HIV-1-infected patients: the TRILOBITHE pilot study

OBJECTIVES

While the use of dual antiretroviral therapies could reduce the toxicity of antiretroviral treatment in treatment-experienced HIV-1-infected patients, it is crucial to know if reducing the number of drugs could lead to an adverse increase in inflammation and activation markers.

METHODS

This was a cross-sectional pilot study conducted at the HIV-1 Unit at the Tertiary University Hospital in Madrid, Spain, evaluating biomarkers of activation [interferon-γ-induced protein 10 (IP10), high-sensitivity C-reactive protein (hs-CRP), soluble CD14 (sCD14) and sCD163], inflammation [interleukin-6 (IL-6)], blood coagulation (d-dimer), and immune response [interferon (IFN)-γ, tumour necrosis factor (TNF)-α and IL-4] in three groups of suppressed HIV-1-infected patients: patients continuing on triple therapy (26 patients), and patients who switched from triple to dual therapy, at 24 or 48 weeks after switching (13 and 36 patients, respectively).

RESULTS

Demographic and immunovirological parameters were similar in the three groups of patients. IL-6 and sCD14 levels were lower in patients at 48 weeks after switching to dual therapy compared with those found in patients who continued to receive triple therapy (P = 0.012 and P = 0.001, respectively), with no differences in the levels of the remaining biomarkers. Among patients with nadir CD4 count ≤ 200 cells/μL, sCD14 levels were lower in patients who had been on dual therapy for 48 weeks (14 patients) compared with those found in patients who received ongoing triple therapy (11 patients; P = 0.029), with no differences in the levels of the other biomarkers.

CONCLUSIONS

HIV-1-infected patients receiving dual regimens showed similar or even lower levels of inflammatory and activation markers compared with those found in patients who received ongoing triple therapy. Of note, similar data were obtained in patients with low nadir CD4 count.