Dual Raltegravir-Etravirine Combination as Maintenance Regimen in Virologically Suppressed HIV-1-Infected Patients

Lamivudine-based two-drug regimens with dolutegravir or protease inhibitor: Virological suppression in spite of previous therapy failure or renal dysfunction

BACKGROUND

Two-Drug Regimens (2DR) have proven effective in clinical trials but real-world data, especially in resource-limited settings, is limited.

OBJECTIVES

To evaluate viral suppression of lamivudine-based 2DR, with dolutegravir or ritonavir-boosted protease inhibitor (lopinavir/r, atazanavir/r or darunavir/r), among all cases regardless of selection criteria.

PATIENTS AND METHODS

A retrospective study, conducted in an HIV clinic in the metropolitan area of São Paulo, Brazil. Per-protocol failure was defined as viremia above 200 copies/mL at outcome. Intention-To-Treat-Exposed (ITT-E) failure was considered for those who initiated 2DR but subsequently had either (i) Delay over 30 days in Antiretroviral Treatment (ART) dispensation, (ii) ART changed or (iii) Viremia > 200 copies/mL in the last observation using 2DR.

RESULTS

Out of 278 patients initiating 2DR, 99.6% had viremia below 200 copies/mL at last observation, 97.8% below 50 copies/mL. Lamivudine resistance, either documented (M184V) or presumed (viremia > 200 copies/mL over a month using 3TC) was present in 11% of cases that showed lower suppression rates (97%), but with no significant hazard ratio to fail per ITT-E (1.24, p = 0.78). Decreased kidney function, present in 18 cases, showed of 4.69 hazard ratio (p = 0.02) per ITT-E for failure (3/18). As per protocol analysis, three failures occurred, none with renal dysfunction.

CONCLUSIONS

The 2DR is feasible, with robust suppression rates, even when 3TC resistance or renal dysfunction is present, and close monitoring of these cases may guarantee long-term suppression.

HIV and Drug-Resistant Subtypes

Acquired Immunodeficiency Syndrome (AIDS) is a human viral infectious disease caused by the positive-sense single-stranded (ss) RNA Human Immunodeficiency Virus (HIV) (Retroviridae family, Ortervirales order). HIV-1 can be distinguished into various worldwide spread groups and subtypes. HIV-2 also causes human immunodeficiency, which develops slowly and tends to be less aggressive. HIV-2 only partially homologates to HIV-1 despite the similar derivation. Antiretroviral therapy (ART) is the treatment approved to control HIV infection, based on multiple antiretroviral drugs that belong to different classes: (i) NNRTIs, (ii) NRTIs, (iii) PIs, (iv) INSTIs, and (v) entry inhibitors. These drugs, acting on different stages of the HIV life cycle, decrease the patient's total burden of HIV, maintain the function of the immune system, and prevent opportunistic infections. The appearance of several strains resistant to these drugs, however, represents a problem today that needs to be addressed as best as we can. New outbreaks of strains show a widespread geographic distribution and a highly variable mortality rate, even affecting treated patients significantly. Therefore, novel treatment approaches should be explored. The present review discusses updated information on HIV-1- and HIV-2-resistant strains, including details on different mutations responsible for drug resistance.

Long-term follow-up of HIV-1 multi-drug-resistant treatment-experienced participants treated with etravirine, raltegravir and boosted darunavir: towards drug-reduced regimen? ANRS CO3 Aquitaine Cohort 2007-2018

OBJECTIVE

To assess the efficacy of raltegravir, etravirine and darunavir/ritonavir (TRIO regimen) in treatment-experienced patients with human immunodeficiency virus-1 (HIV-1) infection by describing the proportion of patients who experienced virological failure (VF) at Week 24. The secondary objectives were to assess the HIV-1 plasma viral load (pVL) after Week 24, the proportion of patients who were receiving dual therapy or monotherapy at the last visit, and the number of deaths.

METHODS

Patients from the ANRS CO3 Aquitaine Cohort who were prescribed the TRIO regimen between February 2007 and September 2018 were classified into two groups based on their pVL at study inclusion: the virological failure group (VFG; pVL >50 copies/mL) and the virologically suppressed group (VSG; pVL <50 copies/mL). The impact of baseline pVL and genotypic susceptibility score (GSS) on VF was analysed.

RESULTS

In total, 184 patients were enrolled in this study, with 123 (66.8%) in the VFG and 61 (33.2%) in the VSG. The median length of follow-up was 7.5 (interquartile range 4.1-9.6) years, and 29 (15.8%) patients died. Thirty-seven (25.5%) patients experienced VF at Week 24, including 32/145 (32.7%) in the VFG and 5/47 (10.6%) in the VSG (P<0.01). Resistance-associated mutations were detected in integrase, reverse transcriptase and protease for 7/37 (18.9%), 3/37 (8.1%) and 1/37 (2.7%) patients, respectively. High pVL and GSS at baseline were independently associated with VF. At the last visit, 76/184 (41.3%) patients were still receiving the TRIO regimen, while 55/184 (29.9%) were receiving dual therapy and 1/184 (0.5%) was receiving protease inhibitor monotherapy. Among the 56 patients receiving dual therapy or monotherapy, 51 (96.2%) had pVL <50 copies/mL.

CONCLUSION

Despite a high level of mutation resistance at baseline, long-term virological follow-up was favourable and one-third of patients were eligible for drug-reducing strategies.

Long-Term Administration of Abacavir and Etravirine Impairs Semen Quality and Alters Redox System and Bone Metabolism in Growing Male Wistar Rats

Highly active antiretroviral therapy (HAART) is used in HIV-infected patients. Alongside the prolongation of patients' life, adverse side effects associated with long-term therapy are becoming an increasing problem. Therefore, optimizing of HAART is extremely important. The study is aimed at evaluating the toxicity of abacavir and etravirine in monotherapy on the reproductive system, liver, kidneys, and bones in young, sexually mature, male rats. Thirty-six 8-week-old male Wistar rats randomized into three 12-animal groups received either normal saline (control), abacavir 60 mg/kg (AB group), or etravirine 40 mg/kg (ET group) once daily for 16 weeks. Semen morphology, oxide-redox state parameters (MDA, SOD, catalase, GPx, glutathione, GSH/GSSG ratio) in tissue homogenates (testes, liver, kidneys), and serum samples were studied. In bones, microcomputed tomography and a four-point bending test were performed. Total sperm count, sperm concentration, motility, and sperm morphology did not differ significantly in AB or ET groups compared to the control. In the flow cytometry of semen, an increased percentage of cells with denatured DNA was noticed for both tested drugs. However, no significant changes of oxide-redox state in testicular homogenates were found, except of increased SOD activity in the AB-receiving group. Additionally, ET significantly altered catalase and GPx in the liver and SOD activity in kidneys. Abacavir decreased catalase in the liver and GSH levels in kidneys. AB caused significant changes to bone microarchitecture (bone volume fraction, trabecular number, connectivity density, total porosity) and increased Young's modulus. Etravirine had a greater impact on macrometric parameters of bones (tibial index, mid-tibial diameter, femur length). After 4 weeks in the ET group, a lower 1,25-dihydroxyvitamin D₃ serum concentration was found. The results showed that abacavir and etravirine disturb oxidative stress. An increase in the percentage of sperms with chromatin damage suggests decreased fertility in rats receiving the studied drugs. Both drugs affected bone formation in growing rats. Additionally, etravirine disturbed vitamin D metabolism.

Clinical outcomes of two-drug regimens vs. three-drug regimens in antiretroviral treatment-experienced people living with HIV

BACKGROUND

Limited data exist comparing clinical outcomes of two-drug regimens (2DRs) and three-drug regimens (3DRs) in people living with HIV.

METHODS

Antiretroviral treatment-experienced individuals in RESPOND switching to a new 2DR or 3DR from 1/1/12-1/10/18 were included. The incidence of clinical events (AIDS, non-AIDS cancer, cardiovascular disease, end-stage liver and renal disease, death) was compared between regimens using Poisson regression.

RESULTS

Of 9791 individuals included, 1088 (11.1%) started 2DRs and 8703 (88.9%) 3DRs. The most common 2DRs were dolutegravir plus lamivudine (22.8%) and raltegravir plus boosted darunavir (19.8%); the most common 3DR was dolutegravir plus 2 nucleoside reverse transcriptase inhibitors (46.9%). Individuals on 2DRs were older (median 52.6 years [interquartile range 46.7-59.0] vs 47.7 [39.7-54.3]), and a higher proportion had ≥1 comorbidity (81.6% vs 73.9%).There were 619 events during 27,159 person-years of follow-up (PYFU): 540 (incidence rate [IR] 22.5/1000 PYFU [95% CI 20.7-24.5]) on 3DRs, 79 (30.9/1000 PYFU [24.8-38.5]) on 2DRs. The most common events were death (7.5/1000 PYFU [95% CI 6.5-8.6]) and non-AIDS cancer (5.8/1000 PYFU [4.9-6.8]). After adjustment for baseline demographic and clinical characteristics, there was a similar incidence of events on both regimen types (2DRs vs 3DRs IR ratio: 0.92 [0.72-1.19]; p=0.53).

CONCLUSIONS

This is the first large, international cohort assessing clinical outcomes on 2DRs. After accounting for baseline characteristics, there was a similar incidence of events on 2DRs and 3DRs. 2DRs appear to be a viable treatment option with regard to clinical outcomes; further research on resistance barriers and long-term durability of 2DRs is needed.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs): a brief overview of clinically approved drugs and combination regimens

The non-nucleoside reverse transcriptase inhibitors (NNRTIs) are allosteric inhibitors of HIV-1 reverse transcriptase and are classified into generations depending on their discovery and resistance profiles. The NNRTIs are used in combination regimens with antiretroviral agents that target two or more enzymes in the viral life cycle. The combination regimens usually include a backbone of two nucleoside or nucleotide reverse transcriptase inhibitors and a third core agent among the NNRTIs or protease inhibitors. The combination regimens are maintained over long durations and consequently lead to long-term problems, including toxicity, drug-drug interactions, and increasing costs. This brief overview summarizes the pharmacokinetic profiles for NNRTIs and NNRTI-based combination regimens.

Antiretroviral drug reduction in highly experienced HIV-infected patients receiving a multidrug regimen: the ECOVIR study

OBJECTIVES

In a context of life-long therapy, we asked whether it could be possible to reduce the number of antiretroviral drugs without jeopardizing viral suppression.

METHODS

ECOVIR was a prospective study aiming to assess whether in patients on combination ART with ≥4 antiretrovirals for ≥24 weeks and virally suppressed for ≥48 weeks, a drug-reduced (DR) regimen could be proposed. The intervention consisted of discontinuing genotypically less susceptible drugs to reach a DR regimen with ≤3 antiretrovirals. The primary endpoint was the proportion of patients maintaining viral suppression at week (W) 24.

RESULTS

From 89 eligible individuals for the study, a DR regimen was proposed in 86 (97%) patients, of whom 71 were switched to a DR regimen. Baseline characteristics [median (IQR)] were: age 58 (53-65) years, duration of treatment 24 (21-26) years and viral suppression 8 (6-11) years. The cumulative resistance profile showed full resistance to lamivudine/emtricitabine (91%), abacavir (74%), efavirenz/nevirapine (70%), rilpivirine (56%), darunavir (q24h/q12h) (42%/29%), lopinavir (69%), atazanavir (71%) and raltegravir (24%). The final DR regimen consisted of a two-drug or three-drug regimen in 54 patients (76%) and in 17 patients (24%), respectively. The success rate of a DR regimen at W24 was 93.9% (95% CI 84.4-97.6, Kaplan-Meier estimate). Four patients experienced virological failure (at W4, W8 and W12), all with plasma viral load (pVL) <600 copies/mL and no emergence of resistance mutations. The DR strategy allowed a monthly cost saving of 36%.

CONCLUSIONS

In experienced patients with high-level resistance, individualized strategies based on expert advice can offer DR regimen options with fewer drug-drug interactions and a significant economic impact while ensuring virological success.

Dual therapy combining raltegravir with etravirine maintains a high level of viral suppression over 96 weeks in long-term experienced HIV-infected individuals over 45 years on a PI-based regimen: results from the Phase II ANRS 163 ETRAL study

BACKGROUND

Dual therapy combining integrase inhibitors and NNRTIs represents a promising regimen in ageing HIV-infected individuals with long exposure to nucleoside analogues and PIs.

METHODS

The ANRS 163 ETRAL trial (NCT02212379) was a 96 week, multicentre, single-arm study evaluating the efficacy and safety of raltegravir (400 mg twice daily)/etravirine (200 mg twice daily) in individuals >45 years, on a PI-containing regimen who were integrase inhibitor and etravirine naive. The primary endpoint was the proportion of participants with virological success, defined by the absence of virological failure up to week 48. Main secondary outcomes included evolution of metabolic parameters, CD4/CD8 count, bone mineral density and inflammatory markers. The study was designed to show an efficacy >90%, assuming a success rate ≥95%, with a power of 80% and a 5% type-1 error.

RESULTS

One hundred and sixty-five participants (median age 52 years, duration of ART 16.9 years, viral suppression 6.9 years and CD4 count 700 cells/mm3) were enrolled. By ITT analysis, viral suppression was maintained in 99.4% of participants (95% CI = 95.6%-99.9%) at week 48 and 98.7% (95% CI = 95.0%-99.7%) at week 96. Two virological failures occurred (week 24 and week 64) without emergence of integrase inhibitor resistance. Eight participants discontinued raltegravir/etravirine for adverse events, leading to a strategy success rate of 95.1% (95% CI = 90.5%-97.5%) at week 48 and 92.7% (95% CI = 87.5%-95.8%) at week 96. Over 96 weeks, lipid fractions improved (P < 0.001), CD4/CD8 ratio increased, IFNγ-induced protein 10 (IP-10) decreased (-8.1%), soluble CD14 decreased (-27%, P < 0.001) bone mineral density improved and BMI increased.

CONCLUSIONS

Raltegravir plus etravirine dual therapy demonstrated durable efficacy in virologically suppressed ageing patients.

Non-Nucleoside Reverse Transcriptase Inhibitors Join Forces with Integrase Inhibitors to Combat HIV

In the treatment of acquired immune deficiency syndrome (AIDS), the diarylpyrimidine (DAPY) analogs etravirine (ETR) and rilpivirine (RPV) have been widely effective against human immunodeficiency virus (HIV) variants that are resistant to other non-nucleoside reverse transcriptase inhibitors (NNRTIs). With non-inferior or improved efficacy, better safety profiles, and lower doses or pill burdens than other NNRTIs in the clinic, combination therapies including either of these two drugs have led to higher adherence than other NNRTI-containing treatments. In a separate development, HIV integrase strand transfer inhibitors (INSTIs) have shown efficacy in treating AIDS, including raltegravir (RAL), elvitegravir (EVG), cabotegravir (CAB), bictegravir (BIC), and dolutegravir (DTG). Of these, DTG and BIC perform better against a wide range of resistance mutations than other INSTIs. Nevertheless, drug-resistant combinations of mutations have begun to emerge against all DAPYs and INSTIs, attributable in part to non-adherence. New dual therapies that may promote better adherence combine ETR or RPV with an INSTI and have been safer and non-inferior to more traditional triple-drug treatments. Long-acting dual- and triple-therapies combining ETR or RPV with INSTIs are under study and may further improve adherence. Here, highly resistant emergent mutations and efficacy data on these novel treatments are reviewed. Overall, ETR or RPV, in combination with INSTIs, may be treatments of choice as long-term maintenance therapies that optimize efficacy, adherence, and safety.

Maintenance of Viral Suppression after Optimization Therapy from Etravirine Plus Raltegravir to Rilpivirine Plus Dolutegravir in HIV-1-Infected Patients

Non-nucleoside reverse-transcriptase inhibitor plus integrase strand transfer inhibitor–based dual therapies are an attractive simplification, nucleoside reverse transcriptase inhibitor-sparing strategy for experienced human immunodeficiency virus-infected patients. Thus, we performed a 24-week real-life observational study to assess efficacy and safety of switching from raltegravir plus etravirine to dolutegravir plus rilpivirine in 7 previously heavily treated patients. This simplification strategy reduced pill burden and preserved viral suppression in treatment-experienced patients with no major mutations to rilpivirine at historical genotyping.

Two-drug regimens for treatment of naïve HIV-1 infection and as maintenance therapy

As people live longer with HIV infection, there has been a resurgence of interest in challenging the use of three-drug therapy, including two nucleoside reverse transcriptase inhibitors plus a third drug, as initial treatment of HIV infection or for maintenance therapy in virologically suppressed individuals. Although initial studies showed poor efficacy and/or substantial toxicity, more recent regimens have held greater promise. The SWORD-1 and -2 studies were pivotal trials of dolutegravir plus rilpivirine as maintenance therapy in virologically suppressed patients with no history of drug resistance, leading to the US Food and Drug Administration’s approval of the regimen as a small, single tablet. More recently, the GEMINI-1 and -2 studies demonstrated that dolutegravir plus lamivudine is as safe and effective as the same regimen when combined with tenofovir disoproxil fumarate in treatment-naïve individuals. Together, these and other studies of novel two-drug regimens offer the potential for improved tolerability and simplicity, as well as a reduction in cost. We will review historical and recent trials of two-drug therapy for the treatment of HIV-1 infection.

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.

Switch to maraviroc with darunavir/r, both QD, in patients with suppressed HIV-1 was well tolerated but virologically inferior to standard antiretroviral therapy: 48-week results of a randomized trial

OBJECTIVES

Primary study outcome was absence of treatment failure (virological failure, VF, or treatment interruption) per protocol at week 48.

METHODS

Patients on 3-drug ART with stable HIV-1 RNA <50 copies/mL and CCR5-tropic virus were randomized 1:1 to maraviroc with darunavir/ritonavir qd (study arm) or continue current ART (continuation arm).

RESULTS

In June 2015, 115 patients were evaluable for the primary outcome (56 study, 59 continuation arm). The study was discontinued due to excess of VF in the study arm (7 cases, 12.5%, vs 0 in the continuation arm, p = 0.005). The proportion free of treatment failure was 73.2% in the study and 59.3% in the continuation arm. Two participants in the study and 10 in the continuation arm discontinued therapy due to adverse events (p = 0.030). At VF, no emergent drug resistance was detected. Co-receptor tropism switched to non-R5 in one patient. Patients with VF reported lower adherence and had lower plasma drug levels. Femoral bone mineral density was significantly improved in the study arm.

CONCLUSION

Switching to maraviroc with darunavir/ritonavir qd in virologically suppressed patients was associated with improved tolerability but was virologically inferior to 3-drug therapy.

Dual antiretroviral therapy for HIV infection

INTRODUCTION

For two decades, triple combinations of antiretrovirals have been the standard treatment for HIV infection. The challenges of such lifelong therapy include long-term side effects, high costs and reduced drug adherence. The recent advent of more potent and safer antiretrovirals has renewed the interest for simpler HIV regimens. Areas covered: We discuss the pros and cons of dual antiretroviral therapies in both drug-naïve and in treatment-experienced patients with viral suppression (switch strategy). Expert opinion: Some dual antiretroviral regimens are safe and efficacious, particularly as maintenance therapy. At this time, combinations of dolutegravir plus rilpivirine represent the best dual regimen. Longer follow-up and larger study populations are needed before supporting dolutegravir plus lamivudine. In contrast, dual therapy based on maraviroc is less effective. Although dual regimens with boosted protease inhibitors plus either lamivudine or raltegravir may be effective, they are penalized by metabolic side effects and risk for drug interactions. The newest dual regimens could save money, reduce toxicity and spare drug options for the future. For the first time in HIV therapeutics, less can be more. Dual therapy switching has set up a new paradigm in HIV treatment that uses induction-maintenance.