A randomized trial of two-drug versus three-drug tenofovir-containing maintenance regimens in virologically controlled HIV-1 patients

Tenofovir alafenamide plus dolutegravir as a switch strategy in HIV-infected patients: a pilot randomized controlled trial

BACKGROUND

Currently, two-drug antiretroviral regimens are emerging fields in life-long treatment in people living with HIV.

OBJECTIVES

This randomized non-inferiority open-label controlled trial was designed to compare the 48-week efficacy and safety of tenofovir alafenamide plus dolutegravir versus the standard triple therapy in virologically suppressed people living with HIV. To the best of our knowledge this combination has not been studied before.

METHODS

This open-label randomized controlled trial was conducted in treatment-experienced people with HIV who had HIV-RNA < 47 copies/mL for at least two years. Patients received either tenofovir alafenamide plus dolutegravir combination (26 patients) or a standard three-drug regimen (29 patients). The primary outcome was the proportion of patients maintaining HIV-RNA < 47 copies/mL during 48 weeks, and the secondary outcomes were CD4 cell count changes, the adherence rate, and adverse drug reactions, all over 48 weeks of study.

RESULTS

HIV viral load remained undetectable (HIV-RNA < 47 copies/mL) during the 48 weeks of the study in both arms. The absolute CD4 cell count change was not significant between the two groups. The overall proportion of adverse effects in each group was comparable. The rate of adherence to treatment was acceptable in both groups, and no significant difference was observed.

CONCLUSIONS

Treatment simplification with tenofovir alafenamide plus dolutegravir regimen as maintenance therapy was non-inferior in terms of efficacy and safety compared to the standard triple therapy. Comparing efficacy of antiretroviral therapy.

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.

The comparative effectiveness of NRTI-sparing dual regimens in emulated trials using observational data from the Swiss HIV Cohort Study

BACKGROUND

Nucleoside (or nucleotide) reverse transcriptase inhibitors (NRTIs) cause side effects in some patients, prompting the use of either partly or fully NRTI-sparing regimens.

METHODS

We used data from the Swiss HIV Cohort Study to estimate the effectiveness of two new dolutegravir dual regimens relative to the alternative NRTI-sparing dual regimens that our clinicians used previously. We emulated two trials by propensity score matching case patients on the dolutegravir regimen with control patients on an alternative regimen. We analysed the case control sets using a Bayesian Cox model and estimated effectiveness as the percentage still on their trial regimen without virological failure at 48 weeks.

RESULTS

In a comparison of partly NRTI-sparing regimens, 58 cases treated with dolutegravir were matched to 17 controls treated with boosted darunavir (both with lamivudine or emtricitabine). The estimated difference in effectiveness was 15% (95% credible interval [CrI] 2-33) and 12% (95% CrI 0-26) in two sequential analyses 1 year apart. In a comparison of fully NRTI-sparing regimens, 54 cases treated with dolutegravir were matched to 32 controls treated with raltegravir (both with boosted darunavir). The estimated difference in effectiveness was 9% (95% CrI -1-21) and 5% (95% CrI -4-15) in the two sequential analyses.

CONCLUSIONS

Estimates of relative effectiveness suggest that both dolutegravir regimens are not inferior to these alternative regimens. All four regimens seem suitable for patients needing an NRTI-sparing regimen: there were few virological failures and few treatment changes due to toxicity.

Pharmacokinetics of nucleoside/nucleotide reverse transcriptase inhibitors for the treatment and prevention of HIV infection

INTRODUCTION

Despite dramatic increases in new drugs and regimens, a combination of two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) remains the backbone of many regimens to treat HIV.

AREA COVERED

This article summarizes the pharmacokinetic characteristics of approved NRTIs that are currently in the international treatment and prevention guidelines.

EXPERT OPINION

Compared to other NRTIs, tenofovir alafenamide fumarate (TAF) is more advantageous in terms of potency and safety. It is therefore a preferred choice in combination with emtricitabine (FTC) in most HIV treatment guidelines. The efficacy of the two-drug combination of NRTI/Integrase strand-transfer inhibitor, i.e. lamivudine/dolutegravir has been approved as an option for initial therapy. This regimen however has some limitations in patients with HBV coinfection. The two NRTI combinations tenofovir disproxil fumarate (TDF)/FTC and TAF/FTC have also been approved for pre-exposure prophylaxis (PrEP). Interestingly, a promising long-acting nucleoside reverse transcriptase translocation inhibitor, islatravir, formulated for implant was well tolerated and remained effective for up to a year, suggesting its potential as a single agent for PrEP. In the next decade, it remains to be seen whether NRTI-based regimens will remain the backbone of preferred ART regimens, or if the treatment will eventually move toward NRTI-sparing regimens to avoid long-term NRTI-toxicity.

Two's a Company, Three's a Crowd: A Review of Initiating or Switching to a Two-Drug Antiretroviral Regimen in Treatment-Naïve and Treatment-Experienced Patients Living with HIV-1

INTRODUCTION

As HIV has become a manageable chronic condition, a renewed and increased interest in challenging traditional three-drug HIV therapies and moving toward two-drug regimens (2DR) for initial or maintenance treatment in people living with HIV (PLWH) has developed. As PLWH are living longer, continual advancements in antiretroviral regimens have been a focus to provide optimal life-long therapy options. Although early studies may have shown poor outcomes in virologic suppression with 2DR, newer studies and treatment options have emerged to show promise in the management of HIV. The purpose of this review is to evaluate current literature and assess the efficacy of two-drug (2DR) antiretroviral therapy in treatment-naïve and -experienced people living with HIV.

METHODS

A systematic search was performed between January 2009 to January 2020, using EMBASE, MEDLINE, Google Scholar, and bibliographies. Combinations of the following search terms were used: HIV-1 infection, antiretroviral therapy, dual therapy, two-drug regimen, two-drug therapy, two-drug regimen, and 2DR. Included studies were those in the adult population with at least one active comparator, outcomes assessing HIV-1 RNA viral load while on treatment, and written in English.

RESULTS

Thirty-three studies were included, 13 where 2DRs were evaluated as initial therapy (3 studies with extension data) and 15 where 2DRs were evaluated as maintenance or switch therapy (2 studies with extension data).

CONCLUSION

Although 2DRs may not be appropriate in all patient populations, they are being utilized more frequently and have the potential to reduce costs, adverse effects, and drug interactions.

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.

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.

Deficient reporting and interpretation of non-inferiority randomized clinical trials in HIV patients: a systematic review

OBJECTIVES

Non-inferiority (NI) randomized clinical trials (RCTs) commonly evaluate efficacy of new antiretroviral (ARV) drugs in human immunodeficiency virus (HIV) patients. Their reporting and interpretation have not been systematically evaluated. We evaluated the reporting of NI RCTs in HIV patients according to the CONSORT statement and assessed the degree of misinterpretation of RCTs when NI was inconclusive or not established.

DESIGN

Systematic review.

METHODS

PubMed, Web of Science, and Scopus were reviewed until December 2011. Selection and extraction was performed independently by three reviewers.

RESULTS

Of the 42 RCTs (n = 21,919; range 41-3,316) selected, 23 were in ARV-naïve and 19 in ARV-experienced patients. Twenty-seven (64%) RCTs provided information about prior RCTs of the active comparator, and 37 (88%) used 2-sided CIs. Two thirds of trials used a NI margin between 10 and 12%, although only 12 explained the method to determine it. Blinding was used in 9 studies only. The main conclusion was based on both intention-to-treat (ITT) and per protocol (PP) analyses in 5 trials, on PP analysis only in 4 studies, and on ITT only in 31 studies. Eleven of 16 studies with NI inconclusive or not established highlighted NI or equivalence, and distracted readers with positive secondary results.

CONCLUSIONS

There is poor reporting and interpretation of NI RCTs performed in HIV patients. Maximizing the reporting of the method of NI margin determination, use of blinding and both ITT and PP analyses, and interpreting negative NI according to actual primary findings will improve the understanding of results and their translation into clinical practice.

Lamivudine or emtricitabine (XTC)/protease inhibitor dual therapy as a harm-reduction strategy in patients with tenofovir-related renal toxicity: a case-control study

Tenofovir disoproxil fumarate (TDF) is widely used in HIV-infected patients. It is associated with tubular toxicity, but its management is controversial. A possible strategy is to switch to a dual therapy based on lamivudine or emtricitabine (XTC) and protease inhibitors (PIs). A case-control study was designed to evaluate the switch to XTC + PI therapy in patients with TDF-related renal toxicity. A case was defined as a patient who was on TDF/XTC + PI and who switched to XTC + PI. A control was defined as a patient with the same clinical features who remained on TDF/XTC + PI. Twenty-one cases and 21 controls were included. After 48 weeks, no differences in efficacy were observed. No improvement in the glomerular filtration rate as estimated with the Cockroft-Gault formula (eGFR) was seen, but the number of times that patients had values below 60 ml/min was higher with standard TDF/XTC 1 PI treatment than with dual XTC + PI treatment. A switch to dual therapy could be an option for patients at risk of TDF-related renal damage with no relevant risk of virological or immunological failure.

Associations of antiretroviral drug use and HIV-specific risk factors with carotid intima-media thickness

BACKGROUND

Previous research has demonstrated an increase in carotid intima-media thickness (cIMT) in HIV-infected individuals compared to controls. However, the reason for this increased level of subclinical vascular disease is unknown.

OBJECTIVE

To identify HIV-related risk factors for increased cIMT.

METHODS

We evaluated the relationship between HIV-related characteristics (including markers of HIV disease severity and use of antiretroviral therapy) and cIMT measurements in the internal/bulb and common carotid regions among 538 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). We used Bayesian model averaging to estimate the posterior probability of candidate HIV and non-HIV-related risk factors being true predictors of increased cIMT. Variables with a posterior probability of more than 50% were used to develop a selected regression model for each of the anatomic regions.

RESULTS

For common cIMT, the Bayesian model selection process identified age, African-American race, and systolic and diastolic blood pressure with probability more than 95%, HDL cholesterol with probability 85% and Hispanic ethnicity with probability 51%. Among the HIV-related factors included in the analysis, only tenofovir use was selected (51% probability). In the selected model, duration of tenofovir use was associated with lower common cIMT (-0.0094 mm/year of use; 95% confidence interval: -0.0177 to -0.0010). For internal cIMT, no HIV-related risk factors were above the 50% posterior probability threshold.

CONCLUSION

We observed an inverse association between duration of tenofovir use and common carotid cIMT. Whether this association is causal or due to confounding by indication needs further investigation.