Antiretroviral regimens sparing agents from the nucleoside(tide) reverse transcriptase inhibitor class: a review of the recent literature

Clinical Profile and Adverse Effects of Dolutegravir Treatment in HIV-Positive Patients: A Prospective Observational Study

Background The emergence of dolutegravir (DTG) within antiretroviral therapy (ART) has drastically improved the management of HIV/AIDS, marking a shift toward a chronic manageable condition. Nevertheless, concerns persist regarding the real-world tolerability and adverse effects (AEs) of DTG. Objective This study aims to explore the clinical characteristics, adverse reactions, and adherence to treatment with DTG among HIV-positive individuals. Methods Through a prospective approach, we examined HIV-positive patients undergoing DTG-based ART regimens. Key parameters, including socio-demographic data, treatment adherence, and clusters of differentiation 4 (CD4) count, were evaluated. Enrolled patients were followed up for six months for the development of comorbidities and AEs. Results Initial observations indicate successful viral suppression and enhanced CD4 counts with DTG-based regimens, t(318)=2.0664, p=0.0392. However, a subset of participants experienced AEs such as neuropsychiatric symptoms (headaches and mood fluctuations), unintended weight gain, and other comorbidities linked to prolonged ART usage. Conclusion While DTG-based therapies offer substantial advantages in HIV/AIDS management, such as rapid viral suppression and reduced toxicity, ongoing vigilance for adverse effects, particularly neuropsychiatric symptoms and metabolic disturbances, is imperative for optimizing patient care. Further research is necessary to fully elucidate the safety profile of DTG in real-world scenarios and mitigate potential adverse reactions.

Studying the Changes in Physical Functioning and Oxidative Stress-Related Molecules in People Living with HIV after Switching from Triple to Dual Therapy

BACKGROUND

Physical activity could increase the production of oxidative stress biomarkers, affecting the metabolism and excretion of antiretroviral drugs and, consequently, the clinical outcome. Nowadays, people living with HIV (PLWH) are mostly switching from triple to dual therapy, but no data are available in terms of physical functioning and oxidative stress. The aim of this study was to evaluate if some antioxidant biomarkers and physical functioning tests could be different according to triple or dual antiretroviral therapy.

METHODS

PLWH were evaluated at baseline (BL), while treated with three drugs, and six months after the switch to dual therapy. Physical functioning was quantified using validated tools. Mitochondrial and cytosol antioxidant molecules were evaluated through liquid chromatography.

RESULTS

Twenty-five patients were analyzed. A statistically significant difference between triple and dual therapy was found for mitochondrial glutathione, but not for physical tests. Evaluating differences between physically active and inactive individuals, the following statistically significant differences were suggested, considering triple therapy (mitochondrial n-formyl-methionine p = 0.022, triglycerides p = 0.023) and double therapy (mitochondrial glycine p = 0.035, cytosol glutamic acid p = 0.007, cytosol s-adenosylmethionine p = 0.021).

CONCLUSIONS

For the first time, this study suggests possible differences in terms of antioxidant molecules and physical functioning in PLWH switching from triple to dual therapy.

Machine learning aided multiscale modelling of the HIV-1 infection in the presence of NRTI therapy

Human Immunodeficiency Virus (HIV) is one of the most common chronic infectious diseases in humans. Extending the expected lifetime of patients depends on the use of optimal antiretroviral therapies. Emergence of the drug-resistant strains can reduce the effectiveness of treatments and lead to Acquired Immunodeficiency Syndrome (AIDS), even with antiretroviral therapy. Investigating the genotype-phenotype relationship is a crucial process for optimizing the therapy protocols of the patients. Here, a mathematical modelling framework is proposed to address the impact of existing mutations, timing of initiation, and adherence levels of nucleotide reverse transcriptase inhibitors (NRTIs) on the evolutionary dynamics of the virus strains. For the first time, the existing Stanford HIV drug resistance data have been combined with a multi-strain within-host ordinary differential equation (ODE) model to track the dynamics of the most common NRTI-resistant strains. Overall, the D4T-3TC, D4T-AZT and TDF-D4T drug combinations have been shown to provide higher success rates in preventing treatment failure and further drug resistance. The results are in line with the genotype-phenotype data and pharmacokinetic parameters of the NRTI inhibitors. Moreover, we show that the undetectable mutant strains at the diagnosis have a significant effect on the success/failure rates of the NRTI treatments. Predictions on undetectable strains through our multi-strain within-host model yielded the possible role of viral evolution on the treatment outcomes. It has been recognized that the improvement of multi-scale models can contribute to the understanding of the evolutionary dynamics, and treatment options, and potentially increase the reliability of genotype-phenotype models.

Case study: New onset of neuropsychiatric symptoms following switching to a dolutegravir regimen

Although reports of neuropsychiatric side effects have been reported with efavirenz, these have been limited in comparison with regard to the now recommended dolutegravir regimens. We present a patient with new onset neuropsychiatric manifestations secondary to dolutegravir that resulted in significant physical injuries. The patient was initiated on risperidone for symptomatic control which was subsequently weaned and discontinued following reverting to an original efavirenz antiretroviral regimen, with resolution of neuropsychiatric symptoms. Neuropsychiatric side effects are increasingly noted with dolutegravir, and these should be monitored for on initiation and switching of treatment regimens.

Switching to a Dual-Drug Regimen in HIV-Infected Patients Could Be Associated With Macrophage Activation?

Objectives: The aim of this study was to evaluate the effect on immune activation of switching from a triple-drug to a dual-drug regimen in HIV-1 infected patients on successful combination antiretroviral treatment (cART). Immunadapt is a prospective study evaluating the impact of cART simplification on immune activation.

Methods: We prospectively collected blood samples in HIV-1 infected patients on stable and successful cART switching from triple to dual regimens as a simplifying strategy. We compared immune activation markers: high sensitivity CRP, IL-1, IL-6, IL-8, IP-10, MCP-1, TNF-alpha, soluble CD14 (sCD14), soluble CD163 (sCD163), lipopolysaccharide binding protein, and D-dimer before cART change and at least 6 months after the switch. Patients were stratified according to low or high risk factors of immune activation (low CD4 nadir, previous AIDS-defining condition or very-low-level viremia during follow-up).

Results: From April 2019 to May 2020, 20 subjects were included (mean age 57 years, 25 years since HIV infection, CD4 666 cells/mm3, CD8 766 cells/mm3, CD4/CD8 0.94, CD4 nadir 326 cells/mm3, 15% with AIDS, 18 years on cART, 6 cART regimens received, current cART duration: 56 months). Fourteen patients were prescribed Dolutegravir + Rilpivirine and six received Dolutegravir + Lamivudine. After 6.9 months, a significant sCD163 increase (+ 25.5% vs. + 0.5%, p = 0.02) was observed in subjects with high risk factors, despite maintaining a viral load <50 cp/ml.

Conclusion: cART simplification in favor of dual therapy is associated with macrophage activation in patients at risk of immune activation despite sustained virological control. Risk factors should thus be considered before generalizing such strategies.

Risk of failure in dual therapy versus triple therapy in naïve HIV patients: a systematic review and meta-analysis

OBJECTIVES

Several attempts have been made to test different drug-sparing strategies to reduce the drug-burden and drug-related toxicities. The objective of this meta-analysis was to evaluate the relative risk (RR) of failure of dual therapies compared to triple therapies in HIV-naïve patients.

METHODS

We searched MEDLINE, Google Scholar and the Cochrane Library. The following criteria were used: present data from original articles comparing the two treatment regimens; published from January 2007 up to January, 2020. No language or study design restriction was applied. Subjects were HIV-positive naïve patients treated with dual or triple antiretroviral therapy (ART). A systematic review and meta-analysis was performed. Treatment failure (TF) was the primary outcome evaluated; heterogeneity was assessed using the Q statistic and I².

RESULTS

Fourteen studies were included, allowing a meta-analysis on 5205 patients. The meta-analysis performed on studies that presented data at 48 weeks showed that the RR of TF (RR > 1 favouring triple therapy) in 10 studies was 1.20 (95% confidence interval (CI): 0.91-1.59, I²: 49.2%); the RR of virological failure (VF) in eight studies was 1.54 (95% CI: 0.84-2.86, I²: 54%); the RR of adverse drug reaction leading to discontinuation of the regimen at 48 weeks in eight studies was 0.76 (95% CI: 0.43-1.33, I²: 17.7%). In patients with less than 200 CD4+, the RR of TF in two studies without maraviroc was 2.09 (95% CI: 1.05-4.17, I²: 0.0%). Regarding the studies at 96 weeks there was no difference except in rate of development of resistance, RR 1.94 (95% CI: 1.06-3.53, I²: 6.2%).

CONCLUSION

Dual therapies are as effective as those with three drugs, showing no difference according to the different dual therapies, except in patients with less than 200 CD4; however, they are associated with a higher selection of resistance-associated mutations at 96 weeks of therapy.

Efficacy and Safety of Switching to Dolutegravir With Boosted Darunavir in Virologically Suppressed Adults With HIV-1: A Randomized, Open-Label, Multicenter, Phase 3, Noninferiority Trial: The DUALIS Study

Background

Dolutegravir (DTG) and boosted darunavir (bDRV) are potent antiretrovirals with a high resistance barrier and might be valuable switch options for people with HIV (PWH).

Methods

DUALIS, a randomized, open-label, phase 3b, noninferiority clinical trial, compared the switch to DTG + bDRV (2DR) with continuation of 2 nucleoside reverse transcriptase inhibitors (2NRTI) + bDRV (3DR). PWH with HIV RNA <50 copies/mL taking 2NRTI + bDRV (3DR) for ≥24 weeks (1 accepted blip <200 copies/mL) were randomized to either switch to DTG 50 mg + DRV 800 mg (boosted with 100 mg of ritonavir) or continue taking 3DR. The primary end point (PE) was the proportion of HIV RNA <50 copies/mL at week (W) 48. Change in NRTI backbone was not classified as failure. The estimated sample size for PE analysis was 292; the noninferiority margin was ≤-10.0%.

Results

In total, 263 subjects were randomized and treated (2DR n = 131, 3DR n = 132; 90.1% male; 89.7% Caucasian; median age [interquartile range], 48 [39-54] years). At W48, 86.3% (n = 113/131) of the 2DR subject and 87.9% (n = 116/132) of the 3DR subjects had HIV RNA <50 copies/mL; the difference between arms was -1.6% (95.48% CI, based on the adjusted alpha level accounting for the interim analysis at W24, -9.9% to +6.7%; discontinuations due to adverse events: 2DR, 4.6% [n = 6]; 3DR, 0.8% [n = 1]). Kaplan-Meier estimates of confirmed HIV RNA ≥50 copies/mL at W48 were 1.6% (n = 2) in the 2DR and 3.1% (n = 4) in the 3DR group. Development of treatment-emergent resistance was not observed.

Conclusions

Switching to DTG + bDRV was noninferior to continuing 3DR in subjects already treated with bDRV.

Dolutegravir/rilpivirine for the treatment of HIV-1 infection

Much progress has been made in the development of antiretroviral therapies (ARTs) for HIV-1 infection. Beginning a little over a decade ago, single tablet combination regimens (STRs) became available, and subsequently, newer STR formulations with improved safety profiles have emerged. Recently, there is a growing interest in regimen simplification with the primary goal of further reducing long-term toxicities of ART and improving medication adherence. Dolutegravir/rilpivirine (DTG/RPV) was approved by the US Food and Drug Administration (FDA) as the first dual antiretroviral STR for the maintenance therapy of HIV-1 infection. Following an extensive review of all published papers on RPV and DTG, administered alone and in combination, extracted from databases including PubMed, Google scholar, and EMBASE, as well as drug package inserts and conference abstracts and proceedings, this review discusses the chemical properties and composition, pharmacodynamics and pharmacokinetic properties, clinical trial efficacy and safety data, as well as important drug-drug interactions associated with DTG/RPV. An expert opinion section discusses ideal candidates for DTG/RPV in the context of available but limited data and in comparison to currently available and emerging ART alternatives.

Biochemical and inflammatory modifications after switching to dual antiretroviral therapy in HIV-infected patients in Italy: a multicenter retrospective cohort study from 2007 to 2015

BACKGROUND

Triple-drug regimens are the gold standard for HIV therapy. Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) reducing regimens are used to decrease drugs toxicity, exposure and costs. Aim of our study was to evaluate trends of biochemical and inflammatory indices in patients switching to dual therapy (DT).

METHODS

We included patients that a) switched to a DT from 2007 to 2015 from a tenofovir/abacavir-based triple regimen b) previously maintained a triple and c) subsequently a dual regimen for 12 months with virological suppression. We retrieved data measured at 5 points (at the switch, 6 and 12 months before and after switch). We used platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR) and CD4/CD8 ratio as inflammatory indices. We assessed temporal trends of viro-immunological, biochemical and inflammatory parameters.

RESULTS

Overall, 364 and 65 patients switched from a tenofovir- and an abacavir-triple regimen, respectively. In the tenofovir-reducing group, creatinine clearance and lipids raised after the switch. There was a significant increase in both CD4+ cells and CD4/CD8. CD8+ cells rose after the switch, while opposite trend was found for PLR. In the abacavir-reducing group total lipids showed a decrease during the first 6 months after the switch and then stabilized. An increase of CD4+ and a decrease of CD8+ cells was observed during the study period, although not statistically significant. While CD4/CD8 remained stable after simplification, PLR decreased significantly after 6 months, then returning to baseline. CD8+ cells increased in the tenofovir-reducing group despite a viro-immunological response. Intriguingly, PLR decreased, maintaining this trend for 12 and 6 months after tenofovir and abacavir interruption respectively.

CONCLUSIONS

Increased PLR has been linked to hypercholesterolemia and metabolic-syndrome, while high CD8+ cells count to increased risk of non-AIDS-related events regardless of CD4 T-cell recovery and to virological failure. Whether these findings may have clinical implications, and which role DT plays on the immune system and on inflammation should be further investigated.

Current and emerging two-drug approaches for HIV-1 therapy in ART-naïve and ART-experienced, virologically suppressed patients

INTRODUCTION

Current guidelines recommend a 2-drug antiretroviral regimen as an alternative to triple antiretroviral therapy (ART) in selected patients to reduce long-term toxicity and costs.

AREAS COVERED

This review is intended to provide insight into the efficacy, safety and tolerability of 2-drug versus 3-drug ART in naïve and in treatment-experienced virologically-suppressed patients.

EXPERT OPINION

Dual therapy regimens are not feasible in HBV-coinfected individuals and should not be applied during pregnancy. Positive data on 2-drug ART in drug naïve patients are still limited, while, in virologically-suppressed individuals, several regimens have shown non-inferiority as compared to 3-drug regimens. The strongest evidence of efficacy applies to ritonavir-boosted PI regimens combined with lamivudine and to dolutegravir with rilpivirine. Dual therapies showed improved renal function and bone mineral density over tenofovir disoproxil fumarate-based 3-drug regimens. There are also great expectations for ongoing phase 3 trials testing dolutegravir with lamivudine. New and future single tablet co-formulations of dual regimens are expected to improve their suitability. Despite the lack of comparison with tenofovir alafenamide-based 3-drug regimens, the 2-drug regimens showing consistent non-inferiority and safety versus 3-drug regimens will challenge the current paradigm of 3-drug ART.

Removing inactive NRTIs in a salvage regimen is safe, maintains virological suppression and reduces treatment costs: results from the VERITAS study (TMC114HIV4054)

BACKGROUND

Despite the benefit of maintaining inactive Nucleotide/side reverse transcriptase inhibitors (NRTIs) in salvage regimens, they are associated with increased toxicity and treatment costs. Current evidence suggests that NRTI-sparing regimens in patients failing ART are non-inferior to NRTI-including regimens. This study aimed to evaluate the impact of removing at least one inactive NRTI on virologic, safety, and financial outcomes.

METHODS

Drug-resistant, virologically suppressed patients with CD4 >250 cells/ml on a stable regimen of four or more antiretrovirals (ARVs) were enrolled in a 48-week prospective, open-label pilot trial. One inactive NRTI was removed at baseline. Patients taking over five ARVs had a second inactive NRTI removed at 24 weeks. Viral load, CD4 count, and adverse events were assessed at baseline, 24, and 48 weeks.

RESULTS

Thirty-one male patients participated. Twenty-nine (94%) patients had lamivudine (3TC) or emtricitabine (FTC) removed and four patients had an additional NRTI removed. One patient was excluded at week 26 for discontinuing an active NRTI. All patients maintained undetectable viral loads at weeks 24 (100%) and 48 [PP = 100%; Intent-to-treat (ITT) = 97%]. At 48 weeks, patients had a median gain of 20 CD4 (IQR: - 50, +133; mean +39) compared to baseline. Three patients exhibited Grade III bilirubin elevation (two Grade II and one Grade III at baseline), which returned to baseline levels. No serious adverse events were observed. Removal of one or two ARVs equated to a mean annual savings of $3319 CDN (11%) and $8630 CDN (24%), respectively.

CONCLUSION

Removing inactive NRTIs in patients with a controlled viral load appears to be safe, maintains virological suppression, and reduces treatment costs.

Increased CD127+ and decreased CD57+ T cell expression levels in HIV-infected patients on NRTI-sparing regimens

BACKGROUND

NRTIs-sparing regimens exert favourable profiles on T-cell homeostasis associated parameters. Our aim was to analyze the effect of NRTIs sparing regimen (NRTI-sparing-cART) vs NRTIs-containing regimen (NRTI-cART), on T-cell homeostasis associated parameters in naive HIV-infected patients.

METHODS

Biomarkers of cell survival (CD127) and replicative senescence (CD57), were measured by multiparametric flow cytometry for T-cell phenotyping on peripheral blood mononuclear cells (PBMCs) samples just before (baseline) and after 48 weeks of undetectable viral load in patients on NRTI-sparing-cART (N = 13) and NRTI-cART (N = 14). After 48 weeks a subgroup of patients (n = 5) on NRTI-cART switched to NRTI-sparing-cART for another additional 48 weeks. In vitro assays were performed on PBMCs from HIV-uninfected healthy donors exposed or not to HIV. To analyze the independent factors associated with type of cART bivariate and stepwise multivariate analysis were performed after adjusting for basal CD4+, CD8+ and nadir CD4+ T-cell counts.

RESULTS

After 48 weeks of a NRTI-sparing-cART vs NRTI-cART patients have higher effector memory (EM) CD4+ CD127+ T-cell levels, lower EM CD4+ CD57+ T-cell levels, higher CD8+ CD127+ T-cell levels, lower CD8+ CD57+ T-cell levels and higher memory CD8+ T-cell levels. This effect was confirmed in the subgroup of patients who switched to NRTI-sparing-cART. In vitro assays confirmed that the deleterious effect of a NRTIs-containing regimen was due to NRTIs.

CONCLUSIONS

The implementation of NRTI-sparing regimens, with a favourable profile in CD127 and CD57 T-cell expression, could benefit cART-patients. These results could have potential implications in a decrease in the number of Non-AIDS events.

Chronic Kidney Disease and Antiretroviral Therapy in HIV-Positive Individuals: Recent Developments

Chronic kidney disease (CKD) has emerged as an important health concern in HIV-positive individuals. Preventing long-term kidney toxicity from an antiretroviral therapy is therefore critical. Selected antiretroviral agents, especially tenofovir disoproxil fumarate (TDF) and some ritonavir-boosted protease inhibitors (PI/rs), have been associated with increased risk of CKD. However, the CKD risk attributable to these agents is overall small, especially in those with low baseline risk of CKD and normal renal function. CKD risk in HIV-positive individuals can be further minimized by timely identification of those with worsening renal function and discontinuation of potentially nephrotoxic agents. Clinicians can use several monitoring tools, including the D:A:D risk score and routine measurements of estimated glomerular filtration (eGFR) and proteinuria, to identify high-risk individuals who may require an intervention. Tenofovir alafenamide (TAF), a TDF alternative, promises to be safer in terms of TDF-associated kidney and bone toxicity. While the short-term data on TAF does indicate lower eGFR decline and lower risk of proteinuria (vs. TDF), long-term data on renal safety of TAF are still awaited. Promising results have also emerged from recent trials on alternative dual-therapy antiretroviral regimens which exclude the nucleoside(tide) reverse transcriptase class as well as possibly the PI/rs, thereby reducing the drug burden, and possibly the toxicity. However, long-term safety or benefits of these dual-therapy regimens are still unclear and will need to be studied in future prospective studies. Finally, addressing risk factors such as hypertension and diabetes will continue to be important in this population.

Switch to Dolutegravir plus Rilpivirine Dual Therapy in cART-Experienced Subjects: An Observational Cohort

INTRODUCTION

Little information is available on the efficacy and safety of the dual combination of ripivirine plus dolutegravir. This work aims at beginning to fill this gap.

METHODS

All HIV-1 infected subjects treated with ripivirine plus dolutegravir between October 2014 and September 2015 in eight Italian centres were included in an observational cohort. Data were collected at baseline and at weeks 4, 12, 24 and 48.

RESULTS

One hundred and thirty-two subjects were followed for a median of 24 months, mean 33 months. One subject discontinued the study drug at week 24 for headache, one for drug interaction and one died after week 24 of illicit drug abuse. The mean age was 51.8, females 31.7% and non-caucasians 10%. Fifty-seven (43.2%) had at least one failure in their treatment history. Reasons for switching were simplification (53.0%), toxicity (34.8%), drug interactions (n = 7), persistent low-level viremia (n = 4), non-adherence (n = 3) and viral failure (n = 2). Sixty patients (45.5%) had reverse transcriptase (RT) mutations and 69 (44,7%) had protease (PR) mutations. Sixteen had baseline viral replication, 27 had < 50 HIV-1 RNA copies/mL and in 89 (67.4%) no virus was detected (NVD, 0 copies/mL). At w4, 114 (86.4%) had NVD, 15 had 1 to 49 HIV-1 RNA copies/mL and 3 had 50 to 57 copies/mL. At week 24 one subject had viral rebound without mutations due to missed drug refill, 19 had 1 to 49 copies/mL, and 112 had NVD. All 132 subjects were tested at weeks 4 and 24. Of the 50 subjects who had a 48-week follow-up, one had a treatment interruption, four had 1 to 49 copies/mL and 45 had NVD. Among the entire population, one subject had low-level, one intermediate and 4 high-level resistance to rilpivirine: none failed by week 48. Mean serum creatinine increased by +0.1 mg/dL. During the follow-up one patient reported headache and insomnia.

CONCLUSIONS

Ripivirine plus dolutegravir proved safe and effective in this cohort of non-naïve HIV-1 infected subjects.

Dolutegravir monotherapy as treatment de-escalation in HIV-infected adults with virological control: DoluMono cohort results

BACKGROUND

The potential toxicity of long-term antiretroviral therapy (ART) requires ongoing investigation of novel strategies for treatment of HIV-infected patients. Monotherapy with the integrase inhibitor (INSTI) dolutegravir (DTG) may offer a favourable safety profile. Additionally, DTG has a high barrier of resistance, crucial for successful maintenance of virological control. However, published data is sparse.

METHODS

Retrospective, single-centre cohort study. We enrolled patients on suppressive ART who were switched to DTG monotherapy in routine clinical practice and fulfilled the following inclusion criteria: HIV RNA level <50 copies/ml for ≥6 months at time of switch (one blip <200 copies/ml with re-suppression accepted), no known INSTI resistance or prior INSTI failure, no replicative HBV infection and no history of AIDS.

RESULTS

We identified 31 patients with 24-weeks of follow-up data. Previous ART included a non-nucleoside reverse transcriptase inhibitor, a boosted protease inhibitor or an INSTI in 32%, 6% and 61% of patients, respectively. At week 24, HIV RNA remained <50 copies/ml in all but two patients (94%). One patient chose to discontinue DTG monotherapy and another developed confirmed virological failure (HIV RNA 538 copies/ml) with new INSTI mutations (Q148H/G140S). Immune status and renal and metabolic function showed no statistically significant changes, apart from a significant decrease in gamma-glutamyl transferase.

CONCLUSIONS

De-escalating to DTG monotherapy in selected patients might be a safe and feasible option. However, in one case evolution of INSTI resistance was observed. Further studies should assess particular risk factors for DTG monotherapy failure. In the meanwhile, caution is warranted.

Once-daily maraviroc versus tenofovir/emtricitabine each combined with darunavir/ritonavir for initial HIV-1 treatment

Objective:

The aim of this study was to evaluate the efficacy of maraviroc along with darunavir/ritonavir, all once daily, for the treatment of antiretroviral-naive HIV-1 infected individuals.

Design:

MODERN was a multicentre, double-blind, noninferiority, phase III study in HIV-1 infected, antiretroviral-naive adults with plasma HIV-1 RNA at least 1000 copies/ml and no evidence of reduced susceptibility to study drugs.

Methods:

At screening, participants were randomized 1 : 1 to undergo either genotypic or phenotypic tropism testing. Participants with CCR5-tropic HIV-1 were randomized 1 : 1 to receive maraviroc 150 mg once daily or tenofovir/emtricitabine once daily each with darunavir/ritonavir once daily for 96 weeks. The primary endpoint was the proportion of participants with HIV-1 RNA less than 50 copies/ml (Food and Drug Administration snapshot algorithm) at Week 48. A substudy evaluated bone mineral density, body fat distribution and serum bone turnover markers.

Results:

Seven hundred and ninety-seven participants were dosed (maraviroc, n = 396; tenofovir/emtricitabine, n = 401). The Data Monitoring Committee recommended early study termination due to inferior efficacy in the maraviroc group. At Week 48, the proportion of participants with HIV-1 RNA less than 50 copies/ml was 77.3% for maraviroc and 86.8% for tenofovir/emtricitabine [difference of −9.54% (95% confidence interval: −14.83 to −4.24)]. More maraviroc participants discontinued for lack of efficacy, which was not associated with non-R5 tropism or resistance. Discontinuations for adverse events, Category C events, Grade 3/4 adverse events and laboratory abnormalities were similar between groups.

Conclusion:

A once-daily nucleos(t)ide-sparing two-drug regimen of maraviroc and darunavir/ritonavir was inferior to a three-drug regimen of tenofovir/emtricitabine and darunavir/ritonavir in antiretroviral-naive adults.

Maraviroc, as a Switch Option, in HIV-1-infected Individuals With Stable, Well-controlled HIV Replication and R5-tropic Virus on Their First Nucleoside/Nucleotide Reverse Transcriptase Inhibitor Plus Ritonavir-boosted Protease Inhibitor Regimen: Week 48 Results of the Randomized, Multicenter MARCH Study

BACKGROUND

Alternative combination antiretroviral therapies in virologically suppressed human immunodeficiency virus (HIV)-infected patients experiencing side effects and/or at ongoing risk of important comorbidities from current therapy are needed. Maraviroc (MVC), a chemokine receptor 5 antagonist, is a potential alternative component of therapy in those with R5-tropic virus.

METHODS

The Maraviroc Switch Study is a randomized, multicenter, 96-week, open-label switch study in HIV type 1-infected adults with R5-tropic virus, virologically suppressed on a ritonavir-boosted protease inhibitor (PI/r) plus double nucleoside/nucleotide reverse transcriptase inhibitor (2 N(t)RTI) backbone. Participants were randomized 1:2:2 to current combination antiretroviral therapy (control), or replacing the protease inhibitor (MVC + 2 N(t)RTI arm) or the nucleoside reverse transcriptase inhibitor backbone (MVC + PI/r arm) with twice-daily MVC. The primary endpoint was the difference (switch minus control) in proportion with plasma viral load (VL) <200 copies/mL at 48 weeks. The switch arms were judged noninferior if the lower limit of the 95% confidence interval (CI) for the difference in the primary endpoint was < -12% in the intention-to-treat (ITT) population.

RESULTS

The ITT population comprised 395 participants (control, n = 82; MVC + 2 N(t)RTI, n = 156; MVC + PI/r, n = 157). Baseline characteristics were well matched. At week 48, noninferior rates of virological suppression were observed in those switching away from a PI/r (93.6% [95% CI, -9.0% to 2.2%] and 91.7% [95% CI, -9.6% to 3.8%] with VL <200 and <50 copies/mL, respectively) compared to the control arm (97.6% and 95.1% with VL <200 and <50 copies/mL, respectively). In contrast, MVC + PI/r did not meet noninferiority bounds and was significantly inferior (84.1% [95% CI, -19.8% to -5.8%] and 77.7% [95% CI, -24.9% to -8.4%] with VL <200 and <50 copies/mL, respectively) to the control arm in the ITT analysis.

CONCLUSIONS

These data support MVC as a switch option for ritonavir-boosted PIs when partnered with a 2-N(t)RTI backbone, but not as part of N(t)RTI-sparing regimens comprising MVC with PI/r.

CLINICAL TRIALS REGISTRATION

NCT01384682.

HIV Salvage Therapy Does Not Require Nucleoside Reverse Transcriptase Inhibitors: A Randomized, Controlled Trial

BACKGROUND

Nucleoside reverse transcriptase inhibitors (NRTIs) are often included in antiretroviral regimens in treatment-experienced patients in the absence of data from randomized trials.

OBJECTIVE

To compare treatment success between participants who omit versus those who add NRTIs to an optimized antiretroviral regimen of 3 or more agents.

DESIGN

Multicenter, randomized, controlled trial. (ClinicalTrials.gov: NCT00537394).

SETTING

Outpatient HIV clinics.

PARTICIPANTS

Treatment-experienced patients with HIV infection and viral resistance.

INTERVENTION

Open-label optimized regimens (not including NRTIs) were selected on the basis of treatment history and susceptibility testing. Participants were randomly assigned to omit or add NRTIs.

MEASUREMENTS

The primary efficacy outcome was regimen failure through 48 weeks using a noninferiority margin of 15%. The primary safety outcome was time to initial episode of a severe sign, symptom, or laboratory abnormality before discontinuation of NRTI assignment.

RESULTS

360 participants were randomly assigned, and 93% completed a 48-week visit. The cumulative probability of regimen failure was 29.8% in the omit-NRTIs group versus 25.9% in the add-NRTIs group (difference, 3.2 percentage points [95% CI, -6.1 to 12.5 percentage points]). No significant between-group differences were found in the primary safety end points or the proportion of participants with HIV RNA level less than 50 copies/mL. No deaths occurred in the omit-NRTIs group compared with 7 deaths in the add-NRTIs group.

LIMITATION

Unblinded study design, and the study may not be applicable to resource-poor settings.

CONCLUSION

Treatment-experienced patients with HIV infection starting a new optimized regimen can safely omit NRTIs without compromising virologic efficacy. Omitting NRTIs will reduce pill burden, cost, and toxicity in this patient population.

PRIMARY FUNDING SOURCES

National Institute of Allergy and Infectious Diseases, Boehringer Ingelheim, Janssen, Merck, ViiV Healthcare, Roche, and Monogram Biosciences (LabCorp).

Nanoparticle-Based ARV Drug Combinations for Synergistic Inhibition of Cell-Free and Cell-Cell HIV Transmission

Nanocarrier-based drug delivery systems are playing an emerging role in human immunodeficiency virus (HIV) chemoprophylaxis and treatment due to their ability to alter the pharmacokinetics and improve the therapeutic index of various antiretroviral (ARV) drug compounds used alone and in combination. Although several nanocarriers have been described for combination delivery of ARV drugs, measurement of drug-drug activities facilitated by the use of these nanotechnology platforms has not been fully investigated for topical prevention. Here, we show that physicochemically diverse ARV drugs can be encapsulated within polymeric nanoparticles to deliver multidrug combinations that provide potent HIV chemoprophylaxis in relevant models of cell-free, cell-cell, and mucosal tissue infection. In contrast to existing approaches that coformulate ARV drug combinations together in a single nanocarrier, we prepared single-drug-loaded nanoparticles that were subsequently combined upon administration. ARV drug-nanoparticles were prepared using emulsion-solvent evaporation techniques to incorporate maraviroc (MVC), etravirine (ETR), and raltegravir (RAL) into poly(lactic-co-glycolic acid) (PLGA) nanoparticles. We compared the antiviral potency of the free and formulated drug combinations for all pairwise and triple drug combinations against both cell-free and cell-associated HIV-1 infection in vitro. The efficacy of ARV-drug nanoparticle combinations was also assessed in a macaque cervicovaginal explant model using a chimeric simian-human immunodeficiency virus (SHIV) containing the reverse transcriptase (RT) of HIV-1. We observed that our ARV-NPs maintained potent HIV inhibition and were more effective when used in combinations. In particular, ARV-NP combinations involving ETR-NP exhibited significantly higher antiviral potency and dose-reduction against both cell-free and cell-associated HIV-1 BaL infection in vitro. Furthermore, ARV-NP combinations that showed large dose-reduction were identified to be synergistic, whereas the equivalent free-drug combinations were observed to be strictly additive. Higher intracellular drug concentration was measured for cells dosed with the triple ARV-NP combination compared to the equivalent unformulated drugs. Finally, as a first step toward evaluating challenge studies in animal models, we also show that our ARV-NP combinations inhibit RT-SHIV virus propagation in macaque cervicovaginal tissue and block virus transmission by migratory cells emigrating from the tissue. Our results demonstrate that ARV-NP combinations control HIV-1 transmission more efficiently than free-drug combinations. These studies provide a rationale to better understand the role of nanocarrier systems in facilitating multidrug effects in relevant cells and tissues associated with HIV infection.

A new hypothesis on HIV cure

In this opinion article, I provide the rationale for my hypothesis that nucleoside reverse transcriptase inhibitors (NRTIs) may prevent human immunodeficiency virus (HIV) cure by promoting the survival of cells with integrated provirus. If correct, we may be closer to a cure than we realize.

ARVs: the next generation. Going boldly together to new frontiers of HIV treatment

New antiretrovirals (ARVs), particularly the potentially “game-changing” ARV dolutegravir, offer major potential to meet the compelling need for simpler and better HIV treatment for tens of millions of people in the coming decade. Advantages include substantially lower manufacturing cost, fewer side effects, and less risk of resistance. But key obstacles must be addressed in order to develop and introduce new ARVs in specific combinations optimized for the needs of low- and middle-income countries. Strong leadership will be essential from the global health community to nurture more focused collaboration between the private and public sectors.

Efficacy and safety of switching to raltegravir plus atazanavir dual therapy in pretreated HIV-1-infected patients over 144 weeks: a cohort study

BACKGROUND

To decrease drug burden among HIV-1-positive adults, we need a new gold standard for antiretroviral therapy maintenance strategies.

METHODS

This retrospective study aimed to assess efficacy in maintenance strategy of atazanavir (ATV) and raltegravir (RAL) dual therapy. The proportion of patients with HIV-1 RNA < 40 copies/ml at specific time points was recorded. Immunological response, safety, and pharmacokinetics were assessed.

RESULTS

Overall, 39 patients were switched to a RAL/ATV (n = 32) or RAL/ATV plus ritonavir (n = 7) regimen. Almost all patients (95%) received RAL twice daily. Most patients (70%) received a 400 mg ATV dosing per day, once (26%) or twice daily (44%). The percentages of virological success at weeks 24, 48, 96, and 144 were 92% (95% confidence interval (CI), 83-10), 86% (95% CI, 74-98), 70% (95% CI, 52-88), and 63% (95% CI, 42-84), respectively. Overall, 12 (31%) patients stopped dual therapy: 7 patients because of adverse events, mostly clinical myositis (n = 3). Confirmed virological failure occurred in three patients; two of them developed RAL resistance patterns. A significant increase in the CD4+/CD8 + T-cell ratio was observed at week 48 (p < 0.005). Only grade 1-2 adverse events were observed. Trough plasma levels presented a wide variability. Suggested trough concentrations were achieved in 79% and 94% of patients for ATV and RAL, respectively. An unboosted 400 mg per day ATV dosing seemed to be appropriate, regarding the targeted levels achieved and the lack of grade 3 or 4 hyperbilirubinemia.

CONCLUSIONS

We demonstrated, on a 3-year follow-up, the efficacy and safety of RAL plus ATV maintenance dual therapy.

Dolutegravir: clinical efficacy and role in HIV therapy

The human immunodeficiency virus type-1 (HIV-1) integrase enzyme has recently emerged as a primary alternative target to block viral replication, and integrase strand transfer inhibitors (INSTIs) are now considered an alternative 'third agent' class of antiretroviral (ARV) drugs. Dolutegravir is the first next-generation INSTI showing some novel and intriguing characteristics: it has a favorable pharmacokinetic profile with a prolonged intracellular halflife, rendering feasible a once daily dosing without the need for pharmacokinetic boosting. Secondly, it is largely metabolized via uridine diphosphate glucuronosyltransferase-1A1 with a minor component of cytochrome P450 isoforms, thus allowing a low grade of drug-drug interactions, so that its metabolic profile consents co-administration with the majority of the other ARV drugs without dose adjustments. Lastly, but no less important, virological studies have clearly demonstrated that dolutegravir has a significant activity against HIV-1 isolates showing raltegravir and/or elvitegravir associated resistance mutations. The attributes of once daily administration and the potential to treat INSTI-resistant viruses make dolutegravir an interesting and promising new agent in the treatment of both naïve and experienced HIV-1 subjects. In this review, the main concerns on dolutegravir efficacy are focused through the analysis of the currently available data from clinical studies in naïve and experienced patients, evaluating its possible place within the anti-HIV-1 drug armamentarium. The development of newer once daily, single tablet coformulations improved drug adherence and maximized the success of ARV therapy. Pharmacokinetic studies and dose-ranging trials suggested that dolutegravir is a good candidate for a single tablet regimen in one or more new coformulated pills that will be available in the near future.

Moving away from Ritonavir, Abacavir, Tenofovir, and Efavirenz (RATE)--agents that concern prescribers and patients: a feasibility study and call for a trial

Objectives

Regimens sparing RATE (ritonavir, abacavir, tenofovir, efavirienz) agents might have better long-term safety. We conducted a feasibility exercise to assess the potential for a randomised trial evaluating RATE-sparing regimens.

Design

Observational.

Methods

We first calculated RATE-sparing options available to an average patient receiving RATE agents. We reviewed treatment history and all resistance assays from patients attending the St. Vincent’s Hospital (Sydney) clinic and receiving ≥2 RATE agents (n = 120). A viable RATE-sparing regimen with 2 or 3 fully-active agents was constructed from the following six ‘safer’ agents: rilpivirine or etravirine; atazanavir; raltegravir; maraviroc; and lamivudine. Activity for each drug was predicted as 1 (full-activity), 0.5 or 0 (no activity) using the Stanford mutation database. The utility of maraviroc was calculated assuming both maraviroc activity and inactivity where unknown. The analysis was restricted to regimens for which supporting evidence was identified in the literature or conference proceedings. Finally, we calculated the proportion of patients in the nationally representative Australian HIV Observational Database (AHOD) cohort receiving ≥2 RATE agents (n = 1473) to measure the potential population-level uptake of RATE-sparing agents.

Results

Assuming full maraviroc activity, 117(97.5%) and 107(89.2%) individuals had at least one option with 2 or 3 active RATE-sparing agents, respectively. Assuming no maraviroc activity this decreased to 113(94.2%) and 104(86.7%), respectively. In AHOD, 837(56.8%) patients were receiving ≥2 RATE agents.

Conclusion

Feasible treatment switch options sparing RATE agents exist for the majority of patients. Understanding the pros and cons of switching stable patients onto new RATE-sparing regimens requires evidence derived from randomised controlled trials.