Two-drug regimens for HIV treatment

Combination therapy with three antiretroviral agents has been integral to successful HIV-1 treatment since 1996. Although the efficacy, adverse effects, and toxicities of contemporary three-drug regimens have improved, even the newest therapies have potential adverse effects. The use of two-drug regimens is one way to reduce lifetime exposure to antiretroviral drugs while maintaining the benefits of viral suppression. Multiple large, randomised trials have shown the virological non-inferiority of certain two-drug regimens versus three-drug comparators, including adverse effect differences that reflect known profiles of the antiretroviral drugs in the respective regimens. Two-drug combinations are now recommended in treatment guidelines and include the first long-acting antiretroviral regimen for the treatment of HIV-1. Recommended two-drug regimens differ in their risks for, and factors associated with, virological failure and emergent resistance. The tolerability, safety, metabolic profiles, and drug interactions of two-drug regimens also vary by the constituent drugs. No current two-drug regimen is recommended for people with chronic hepatitis B virus as none include tenofovir. Two-drug regimens have increased options for individualised care.

Altered subcutaneous adipose tissue parameters after switching ART-controlled HIV+ patients to raltegravir/maraviroc

OBJECTIVE

To evaluate the effect on anthropometric, metabolic and adipose tissue parameters of switching ART-controlled persons living with HIV (PLWH) from a protease inhibitor regimen to raltegravir/maraviroc.

DESIGN

Sub-study of the ANRS157 ROCnRAL study with the investigation of subcutaneous abdominal adipose tissue (SCAT) biopsy at inclusion and study end.

METHODS

We performed lipoaspiration of paired SCAT samples, histology on fresh/fixed samples and examined the transcriptomic profile analyzed using Illumina microarrays after RNA extraction. Statistical analyses used the Wilcoxon-paired test.

RESULTS

The patients (n = 8) were mainly male (7/8), aged (mean ± standard error of the mean) 54.9 ± 1.2 years, BMI 26.1 ± 1.2 kg/m2, CD4+ 699 ± 56 cells/mm3, all viral load (VL) <50 copies/ml. After a follow-up of 6 ± 0.5 months, all PLWH remained with VL <50 copies/ml. BMI, trunk and limb fat amounts were unchanged yet systemic insulin resistance increased. Adipose tissue histology was unchanged except for borderline increased adipocyte diameter (P = 0.1). Among the 16 094 RNA transcripts, 458 genes were up-regulated and 244 were down-regulated. Analyses of the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology databases, evaluating modifications in the main functional pathways, revealed that genes related to immune recognition/function were less expressed as were genes encoding T-cell receptor and receptor signaling pathways. The gene expression profiles indicated decreased inflammation but genes involved in adipogenesis and insulin resistance were overexpressed.

CONCLUSION

After 6 months of raltegravir/maraviroc, adipogenesis-related gene profile was enhanced in SCAT, in agreement with a tendency for increased adipocyte size. Enhanced SCAT insulin resistance-related profile was concordant with higher systemic insulin resistance. However, the immune activation/inflammation profile was globally lowered. We propose that raltegravir/maraviroc might favor SCAT gain but reduce inflammation/immune activation.

Optimizing Antiretroviral Therapy in Treatment-Experienced Patients Living with HIV: A Critical Review of Switch and Simplification Strategies. An Opinion of the HIV Practice and Research Network of the American College of Clinical Pharmacy

Simplifying or switching antiretroviral therapy (ART) in treatment-experienced people living with HIV (PLWH) may improve adherence, tolerability, toxicities, and/or drug–drug interactions. The purpose of this review is to critically evaluate the literature for efficacy and safety associated with switching or simplifying ART in treatment-experienced PLWH. A systematic literature search using MEDLINE was performed from January 1, 2010 to April 30, 2018. References within articles of interest, the Department of Health and Human Services guidelines, and conference abstracts were also reviewed. Switch/simplification strategies were categorized as those supported by high-level clinical evidence and those with emerging data. Rates of virologic suppression were noninferior for several switch/simplification strategies when compared to baseline ART. Potential for reducing adverse events was also seen. Additional evidence for some strategies, including most 2-drug regimens, is needed before they can be recommended.

Metabolic complications affecting adipose tissue, lipid and glucose metabolism associated with HIV antiretroviral treatment

Introduction: Efficient antiretroviral-treatment (ART) generally allows control of HIV infection. However, persons-living-with-HIV (PLWH), when aging, present a high prevalence of metabolic diseases. Area covered: Altered adiposity, dyslipidemias, insulin resistance, diabetes, and their consequences are prevalent in PLWH and could be partly related to ART. Expert opinion: At first, personal and lifestyle factors are involved in the onset of these complications. The persistence of HIV in tissue reservoirs could synergize with some ART and enhance metabolic disorders. Altered fat repartition, diagnosed as lipodystrophy, has been related to first-generation nucleoside-reverse-transcriptase-inhibitors (NRTIs) (stavudine zidovudine) and some protease inhibitors (PIs). Recently, use of some integrase-inhibitors (INSTI) resulted in weight/fat gain, which represents a worrisome unresolved situation. Lipid parameters were affected by some first-generation NRTIs, non-NRTIs (efavirenz) but also PIs boosted by ritonavir, with increased total and LDL-cholesterol and triglycerides. Insulin resistance is common associated with abdominal obesity. Diabetes incidence, high with first-generation-ART (zidovudine, stavudine, didanosine, indinavir) has declined with contemporary ART close to that of the general population. Metabolic syndrome, a dysmetabolic situation with central obesity and insulin resistance, and liver steatosis are common in PLWH and could indirectly result from ART-associated fat gain and insulin resistance. All these dysmetabolic situations increase the atherogenic cardiovascular risk.

Antiretroviral exposure and comorbidities in an aging HIV-infected population: The challenge of geriatric patients

As HIV-infected adults on successful antiretroviral therapy (ART) are expected to have close to normal lifespans, they will increasingly develop age-related comorbidities. The objective of this cross-sectional study was to compare in the French Dat’AIDS cohort, the HIV geriatric population, aged 75 years and over, to the elderly one, aged from 50 to 74 years. As of Dec 2015, 16,436 subjects (43.8% of the French Dat’AIDS cohort) were aged from 50 to 74 (elderly group) and 572 subjects (1.5%) were aged 75 and over (geriatric group). Durations of HIV infection and of ART were slightly but significantly different, median at 19 and 18 years, and 15 and 16 years in the elderly and geriatric group, respectively. The geriatric group was more frequently at CDC stage C and had a lower nadir CD4. This group had been more exposed to first generation protease inhibitors and thymidine analogues. Despite similar virologic suppression, type of ART at the last visit significantly differed between the 2 groups: triple ART in 74% versus 68.2%, ART ≥ 4 drugs in 4.7% versus 2.7%; dual therapy in 11.6% versus 16.4% in the elderly group and the geriatric group, respectively. In the geriatric group all co-morbidities were significantly more frequent, except dyslipidemia, 4.3% of the elderly group had ≥4 co-morbidities versus18.4% in the geriatric group. Despite more co-morbidities and more advanced HIV infection the geriatric population achieve similar high rate of virologic suppression than the elderly population. A multidisciplinary approach should be developed to face the incoming challenge of aging HIV population.

CCR5 Revisited: How Mechanisms of HIV Entry Govern AIDS Pathogenesis

The chemokine receptor CCR5 has been the focus of intensive studies since its role as a coreceptor for HIV entry was discovered in 1996. These studies lead to the development of small molecular drugs targeting CCR5, with maraviroc becoming in 2007 the first clinically approved chemokine receptor inhibitor. More recently, the apparent HIV cure in a patient transplanted with hematopoietic stem cells devoid of functional CCR5 rekindled the interest for inactivating CCR5 through gene therapy and pharmacological approaches. Fundamental research on CCR5 has also been boosted by key advances in the field of G-protein coupled receptor research, with the realization that CCR5 adopts a variety of conformations, and that only a subset of these conformations may be targeted by chemokine ligands. In addition, recent genetic and pathogenesis studies have emphasized the central role of CCR5 expression levels in determining the risk of HIV and SIV acquisition and disease progression. In this article, we propose to review the key properties of CCR5 that account for its central role in HIV pathogenesis, with a focus on mechanisms that regulate CCR5 expression, conformation, and interaction with HIV envelope glycoproteins.

Dolutegravir and rilpivirine for the maintenance treatment of virologically suppressed HIV-1 infection

INTRODUCTION

Triple combinations of antiretroviral therapy (ART) drugs are the standard treatment for human immunodeficiency virus (HIV) infection, but the challenges include long-term side effects, high costs, and adherence. The recent advent of potent and well-tolerated ART has renewed the interest for newer ART strategies. A dual regimen with the combination of dolutegravir (DTG) and rilpivirine (RPV), two well-tolerated, metabolic-friendly, and potent drugs could offer additional benefits. Areas covered: A review of recent randomized trials and observational cohorts concerning the use of a dual therapy with DTG plus RPV as a switching strategy in patients with viral suppression. Expert commentary: Currently, data of more of 900 patients switched to this dual regimen are available. This combination shows a high rate of virological suppression, above 90% at 48 weeks, few discontinuations due to adverse events, improvement in bone and kidney parameters for patients discontinuing tenofovir disoproxil fumarate, lack of loss of the inflammatory control achieved with triple therapy, and a neutral effect on lipid parameters. Thus, for the first time, a dual regimen without protease inhibitors is effective, avoiding metabolic side effects and drug interactions. Longer follow-up is needed, but this dual regimen appears as a promising strategy for aging HIV-infected patients.

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.

Two-Drug Treatment Approaches in HIV: Finally Getting Somewhere?

The advent of combination antiretroviral therapy (ART) has significantly decreased AIDS-related morbidity and mortality. Nevertheless, the benefits of ART are only realized through adherence to lifelong treatment. Though contemporary antiretroviral (ARV) drugs have fewer adverse effects in comparison to older ARV drugs, many agents are associated with negative or unknown long-term effects. There is increasing evidence that two-drug (dual-therapy) regimens may be an effective alternative to the currently recommended three-drug (triple-therapy) regimens. In this review, we provide a comprehensive and critical review of recently completed and ongoing trials of dual-therapy regimens in treatment-naïve and treatment-experienced HIV-1-infected patients. We also review current HIV/AIDS society recommendations regarding dual therapy as well as future therapeutic possibilities.

Switch to Ritonavir-Boosted versus Unboosted Atazanavir plus Raltegravir Dual-Drug Therapy Leads to Similar Efficacy and Safety Outcomes in Clinical Practice

Objectives

To assess immunovirological response, safety and pharmacokinetic of NRTI-sparing regimen dual therapy of atazanavir (ATV) and raltegravir (RAL) in maintenance strategy.

Methods

A retrospective analysis was conducted on a cohort of HIV-infected adults followed in French centers (Dat’AIDS cohort), comparing the proportions of virological and therapeutic failures between ATV + RAL and ATV/ritonavir + RAL dual therapy regimens.

Results

283 patients were assessed: 185 switched for ATV + RAL and 98 for ATV/ritonavir + RAL dual therapy. Virological failure rate at week 96 was 13.8% (95% CI, 9.8–17.8), without difference between the two groups (Log-rank Test, p = 0.87). The cumulative percentages of patients remaining free of therapeutic failure at week 24, 48 and 96 of dual therapy were 74.9% (95% CI, 69.9–80.0), 65.4% (95% CI, 59.8–70.9) and 53.4% (95% CI, 47.5–59.2), respectively. Four out of 39 confirmed virological failures developed RAL resistance. By multivariate analysis, virological failure was associated with high HIV-1 RNA zenith (p = 0.02), low CD4+ T-cell count at baseline (p<0.001) and short duration on antiretroviral therapy (p<0.001). Before week 96, dual therapy was discontinued in 44 patients (16%) because of various adverse events, with no difference between the two groups. Minimal plasma levels were targeted in 84% and 87% of patients for ATV and RAL, respectively, and both were significantly higher in ritonavir-boosted regimen.

Conclusions

Emerging RAL-resistance and discontinuations for adverse events resulted in moderate efficacy rates of ATV and RAL dual therapy in heavily pretreated patients.

Modifying Antiretroviral Therapy in Virologically Suppressed HIV-1-Infected Patients

HIV-1-infected patients with suppressed plasma viral loads often require changes to their antiretroviral (ARV) therapy to manage drug toxicity and intolerance, to improve adherence, and to avoid drug interactions. In patients who have never experienced virologic failure while receiving ARV therapy and who have no evidence of drug resistance, switching to any of the acceptable US Department of Health and Human Services first-line therapies is expected to maintain virologic suppression. However, in virologically suppressed patients with a history of virologic failure or drug resistance, it can be more challenging to change therapy while still maintaining virologic suppression. In these patients, it may be difficult to know whether the discontinuation of one of the ARVs in a suppressive regimen constitutes the removal of a key regimen component that will not be adequately supplanted by one or more substituted ARVs. In this article, we review many of the clinical scenarios requiring ARV therapy modification in patients with stable virologic suppression and outline the strategies for modifying therapy while maintaining long-term virologic suppression.

Maraviroc/raltegravir simplification strategy following 6 months of quadruple therapy with tenofovir/emtricitabine/maraviroc/raltegravir in treatment-naive HIV patients

OBJECTIVE

We assessed the virological efficacy of a 6 month maraviroc/raltegravir simplification strategy following 6 months of quadruple therapy combining tenofovir disoproxil fumarate/emtricitabine with maraviroc/raltegravir.

METHODS

HIV-1-infected naive patients were enrolled in an open label, single-arm, Phase 2 trial. All patients received maraviroc 300 mg twice daily, raltegravir 400 mg twice daily and tenofovir/emtricitabine for 24 weeks. Patients with stable HIV-RNA <50 copies/mL stopped tenofovir/emtricitabine at week (W) 24 and pursued maraviroc/raltegravir until W48. The primary endpoint was the virological response defined by HIV-RNA <50 copies/mL at W48.

RESULTS

Thirty-three patients were analysed. Patients were mostly male (94%), Caucasians (91%), MSM (82%); their median age was 42 years. At baseline, median CD4 cell count was 453 cells/mm³ and HIV-RNA was 4.3 log copies/mL. All patients had CCR5-tropic viruses by genotropism and phenotropism assays. All but one patient had an HIV-RNA < 50 copies/mL at W24 and entered the simplification phase. Virological success was maintained at W48 in 88% (90% CI 79%-97%) of patients. N155H mutation was detected at failure in one patient. No tropism switch was observed. Raltegravir and maraviroc plasma exposure were satisfactory in 92% and 79% of 41 samples from 21 patients. Five severe adverse events (SAEs) were observed up to W48; none was related to the study drugs. Four patients presented grade 3 AEs; none was related to the study. No grade 4 AE was observed. No patient died.

CONCLUSIONS

Maraviroc/raltegravir maintenance therapy following a 6 month induction phase with maraviroc/raltegravir/tenofovir/emtricitabine was well tolerated and maintained virological efficacy in these carefully selected patients.

Dutrebis (lamivudine and raltegravir) for use in combination with other antiretroviral products for the treatment of HIV-1 infection

Raltegravir and lamivudine have been part of highly active therapy regimens throughout the past years of antiretroviral therapy. A fixed-dose, single-tablet regimen comprising a non-poloxamer formulation of the integrase inhibitor raltegravir and the transcriptase inhibitor lamivudine (raltegravir/lamivudine; Dutrebis(®)) has been recently licensed for the treatment of HIV-1 infection. In several Phase I pharmacokinetic studies, one Dutrebis (150 mg lamivudine/300 mg raltegravir) fixed-dose combination tablet showed a higher bioavailability but comparable lamivudine and 400 mg raltegravir poloxamer exposures. Thus, the co-administration of raltegravir together with lamivudine created a potent, effective, well-tolerated antiretroviral combination, which could be more convenient for the patient. However, the disadvantage of twice a day administration, and the existence of other fixed-dose combinations limit its widespread clinical use. This article reviews pharmacokinetics data and appraises their potential use in current and future HIV therapy.

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.

Pharmacokinetic and pharmacodynamic evaluation of raltegravir and experience from clinical trials in HIV-positive patients

INTRODUCTION

Raltegravir was the first available integrase inhibitor for treating HIV-positive patients. This review aims to provide an overview of its role in the management of HIV-1 infection, highlighting its key pharmacokinetic and pharmacodynamic properties.

AREAS COVERED

This review covers material searched and obtained through Medline and PubMed up to April 2015.

EXPERT OPINION

Raltegravir for its tolerability, efficacy, few drug-to-drug interactions and for the amount of available data in difficult subgroups of patients is a key drug in the antiretroviral armamentarium. For its weak genetic barrier to resistance and erratic pharmacokinetic profile, it should be administered twice daily and with fully active companion antiretrovirals.

Dual Therapy Treatment Strategies for the Management of Patients Infected with HIV: A Systematic Review of Current Evidence in ARV-Naive or ARV-Experienced, Virologically Suppressed Patients

Objective

We reviewed the current literature regarding antiretroviral (ARV)-sparing therapy strategies to determine whether these novel regimens can be considered appropriate alternatives to standard regimens for the initial treatment of ARV-naive patients or as switch therapy for those patients with virologically suppressed HIV infection.

Methods

A search for studies related to HIV dual therapy published from January 2000 through April 2014 was performed using Biosis, Derwent Drug File, Embase, International Pharmaceutical Abstracts, Medline, Pascal, SciSearch, and TOXNET databases; seven major trial registries, and the abstracts of major conferences. Using predetermined criteria for inclusion, an expert review committee critically reviewed and qualitatively evaluated all identified trials for efficacy and safety results and potential limitations.

Results

Sixteen studies of dual therapy regimens were critiqued for the ARV-naive population. Studies of a protease inhibitor/ritonavir in combination with the integrase inhibitor raltegravir or the nucleoside reverse transcriptase inhibitor lamivudine provided the most definitive evidence supporting a role for dual therapy. In particular, lopinavir/ritonavir or darunavir/ritonavir combined with raltegravir and lopinavir/ritonavir combined with lamivudine demonstrated noninferiority to standard of care triple therapy after 48 weeks of treatment. Thirteen trials were critiqued in ARV-experienced, virologically suppressed patients. The virologic efficacy outcomes were mixed. Although overall data regarding toxicity are limited, when compared with standard triple therapy, certain dual therapy regimens may offer advantages in renal function, bone mineral density, and limb fat changes; however, some dual combinations may elevate lipid or bilirubin levels.

Conclusions

The potential benefits of dual therapy regimens include reduced toxicity, improved tolerability and adherence, and reduced cost. Although the data reviewed here provide valuable insights into the effectiveness and tolerability of dual therapy regimens, it remains unclear whether these potential benefits can be maintained long-term. Appropriately powered studies with longer follow-up periods are needed to more definitively assess potential toxicity reduction advantages with dual therapy.

Maraviroc: a review of its use in HIV infection and beyond

The human immunodeficiency virus-1 (HIV-1) enters target cells by binding its envelope glycoprotein gp120 to the CD4 receptor and/or coreceptors such as C-C chemokine receptor type 5 (CCR5; R5) and C-X-C chemokine receptor type 4 (CXCR4; X4), and R5-tropic viruses predominate during the early stages of infection. CCR5 antagonists bind to CCR5 to prevent viral entry. Maraviroc (MVC) is the only CCR5 antagonist currently approved by the United States Food and Drug Administration, the European Commission, Health Canada, and several other countries for the treatment of patients infected with R5-tropic HIV-1. MVC has been shown to be effective at inhibiting HIV-1 entry into cells and is well tolerated. With expanding MVC use by HIV-1-infected humans, different clinical outcomes post-approval have been observed with MVC monotherapy or combination therapy with other antiretroviral drugs, with MVC use in humans infected with dual-R5- and X4-tropic HIV-1, infected with different HIV-1 genotype or infected with HIV-2. This review discuss the role of CCR5 in HIV-1 infection, the development of the CCR5 antagonist MVC, its pharmacokinetics, pharmacodynamics, drug–drug interactions, and the implications of these interactions on treatment outcomes, including viral mutations and drug resistance, and the mechanisms associated with the development of resistance to MVC. This review also discusses available studies investigating the use of MVC in the treatment of other diseases such as cancer, graft-versus-host disease, and inflammatory diseases.

Virological factors associated with outcome of dual maraviroc/raltegravir therapy (ANRS-157 trial)

OBJECTIVES

ROCnRAL ANRS-157 was a single-arm study designed to evaluate a switch to a maraviroc (300 mg twice a day) plus raltegravir (400 mg twice a day) regimen in virologically suppressed HIV-1-infected patients (ClinicalTrials.gov: NCT01420523). The aim of this work was to investigate the factors associated with virological failure (VF) (5/44 patients) or virological rebound defined as one viral load (VL) >50 copies/mL or VL >1 copy/mL.

METHODS

At baseline (BL), ultradeep sequencing (UDS) of DNA gp120 V3 and integrase regions and quantification of HIV DNA were performed in PBMCs. Tropism, VL, BL ultrasensitive HIV RNA VL, BL HIV DNA VL, subtype, age, ethnicity, transmission group, AIDS status, nadir CD4 and BL CD4 cell count, time since HIV diagnosis, duration of ART and suppressed viraemia, VL zenith, CD4/CD8 ratio and BL CD8 cell count were investigated as potential factors associated with virological rebound.

RESULTS

The proportion of patients with VL <1 copy/mL did not evolve over time. Among the 44 included patients, 3 had minority X4-tropic viruses determined by UDS at BL and one of them presented VF. Minority resistant variants in the integrase gene were detected at BL at two positions (E138 and G140) for three patients who did not have VF. Among all studied factors, none was associated with virological rebound.

CONCLUSIONS

Maraviroc plus raltegravir failed to maintain virological suppression in virologically suppressed HIV-1-infected patients. However, neither minority viral variants nor ultrasensitive viraemia was found to be a predictive factor of VF or virological rebound in this context.

Switch to maraviroc/raltegravir dual therapy leads to an unfavorable immune profile with low-level HIV viremia

Immunovirological consequences of a switch to a maraviroc/raltegravir dual therapy were analyzed in 16 HIV-infected patients with persistent viral load below 50 copies/ml. At 26-week postswitch, the CD4/CD8 ratio decreased and the CD8 T-cell activation increased. A decrease in classical monocytes was associated with a shift toward a proinflammatory monocyte profile and negatively correlated with ultrasensitive viral load. Thus, this therapeutic switch induced a proinflammatory profile probably driven by a slight loss of virus control.

Efficacy and pharmacokinetics of the combination of etravirine plus raltegravir as novel dual antiretroviral maintenance regimen in HIV-infected patients

Novel combination antiretroviral regimens may be needed for selected HIV-infected patients with toxicity or resistance. We evaluated prospectively 25 virologically suppressed patients, largely pretreated (15.6 years on therapy) with antiretroviral drug toxicity (n=19) or interactions (n=9, mainly with chemotherapy against non-Hodgkin lymphoma or anti-HCV therapy), who switched to a dual therapy with etravirine (ETR) plus raltegravir (RAL). Patients were required not to have prior virological failure or resistance to both drugs. After a median follow up of 722 days (473-1088: 53.3 patients-year), there were no cases of transient virological replication or failure. Only 1 patient left therapy at day 10 due to a grade 2 rash, and therefore efficacy by intent-to-treat analysis was 96% at 48 weeks. There were no cases of liver toxicity grade 3-4, and total cholesterol (TC) and triglycerides (TG) levels decrease significantly after initiation (TC, -17 mg/dl; p=0.01; TG, -42 mg/dl; p=0.01), as well as the TC/High density lipoprotein-cholesterol ratio (from 4.35 to 4.28). Geometric mean plasma trough level of RAL was 166 ng/ml (IQR, 40-249), well above the inhibitory concentration 90 (IC(90)). In conclusion, a novel dual therapy with ETR plus RAL is effective and well tolerated, and it could be an option to maintain durable viral suppression in hard-to-treat HIV-infected patients.

Switch strategies in antiretroviral therapy regimens

Despite great advances in antiretroviral therapy in the last decade, several limitations still remain such as adverse effects, lack of adherence and drug-drug interactions. Switching antiretroviral therapy in stable, virologically suppressed patients with the aim of improving tolerability and convenience is an expanding strategy in clinical practice. Several factors need to be taken into consideration when switching a suppressive regimen, such as previous virologic failure, genetic barrier of the new regimen, prior duration of virologic suppression and expected level of adherence. The most frequently used strategies include reductions in the number of pills, drugs or doses. Although switching strategies may be useful, not all the regimens used in clinical practice are based on data from randomized clinical trials and some may not be the best option for certain patients; therefore, therapy should be individualized taking into consideration available information as well as patient and drug characteristics.

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.

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

The nucleoside(tide) reverse transcriptase inhibitors (NRTIs) have traditionally been an important 'back-bone' of an antiretroviral therapy (ART) regimen. However all agents have been associated with both short- and long-term toxicity. There have also been concerns regarding the efficacy and safety of a treatment sequencing strategy in which those with past exposure and/or resistance to one or more NRTIs are re-exposed to 'recycled' NRTIs in subsequent ART regimens. Newer, potent and possible safer, agents from various ART classes continue to become available. There has therefore been growing interest in evaluating NRTI-sparing regimens. In this review, we examined studies of NRTI-sparing regimens in adult HIV-positive patients with varying degrees of ART experience. We found that in treatment experienced patients currently on a failing regimen with detectable viral load, there now exists a robust evidence for the use of NRTI-sparing regimens including raltegravir with a boosted-protease inhibitor with or without a third agent. In those on a virologically suppressive regimen switching to a NRTI-sparing regimen or in those ART-naïve patients initiating an NRTI-sparing regimen, evidence is sparse and largely comes from small exploratory trials or observational studies. Overall, these studies suggest that caution needs to be exercised in carefully selecting the right candidate and agents, especially in the context of a dual-therapy regimen, to minimise the risks of virological failure. There is residual toxicity conferred by the ritonavir boost in protease-inhibitor containing NRTI-sparing regimens. Fully-powered studies are needed to explore the place of N (t)RTI-sparing regimens in the sequencing of ART. Additionally research is required to explore how to minimise the adverse effects associated with ritonavir-based pharmacoenhancement.