Individual patient data meta-analysis of randomized controlled trials of dual therapy with a boosted PI plus lamivudine for maintenance of virological suppression: GeSIDA study 9717

Two-Drug Regimens for HIV-Current Evidence, Research Gaps and Future Challenges

During the last 30 years, antiretroviral treatment (ART) for human immunodeficiency virus (HIV) infection has been continuously evolving. Since 1996, three-drug regimens (3DR) have been standard-of-care for HIV treatment and are based on a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs). The effectiveness of first-generation 3DRs allowed a dramatic increase in the life expectancy of HIV-infected patients, although it was associated with several side effects and ART-related toxicities. The development of novel two-drug regimens (2DRs) started in the mid-2000s in order to minimize side effects, reduce drug-drug interactions and improve treatment compliance. Several clinical trials compared 2DRs and 3DRs in treatment-naïve and treatment-experienced patients and showed the non-inferiority of 2DRs in terms of efficacy, which led to 2DRs being used as first-line treatment in several clinical scenarios, according to HIV clinical guidelines. In this review, we summarize the current evidence, research gaps and future prospects of 2DRs.

Virological outcomes with dolutegravir plus either lamivudine or two NRTIs as switch strategies: a multi-cohort study

OBJECTIVES

To compare the efficacy of dolutegravir plus lamivudine dual therapy (DT) with that of dolutegravir plus two NRTIs triple therapy (TT) as switch strategies.

METHODS

A multicentre cohort of HIV-positive, HBsAg-negative patients with viral suppression (HIV-RNA ≤50 copies/mL) switching to DT or TT was retrospectively selected from the ARCA database. The effect of DT versus TT on virological failure (VF; defined as two consecutive HIV-RNA values >50 copies/mL or one HIV-RNA value ≥200 copies/mL) was evaluated by multivariable Cox regression models, overall and after stratifying for the presence of NRTI resistance-associated mutations (RAMs).

RESULTS

From December 2014 to June 2020, 628 patients were eligible: 118 (18.8%) started tenofovir/emtricitabine/dolutegravir, 306 (48.7%) abacavir/lamivudine/dolutegravir and 204 (32.5%) lamivudine/dolutegravir. The DT group had significantly higher nadir and baseline CD4 counts, a higher duration of viral suppression and a lower prevalence of RAMs at historical genotype. Overall, 41 VF occurred after a median of 1.7 years of follow-up, with a lower, but not statistically significant, rate for DT [versus TT, adjusted HR (aHR) = 0.58, 95% CI = 0.25-1.34]. However, DT was associated with less VF in the absence of RAMs when compared with tenofovir-based TT (aHR = 0.20, 95% CI = 0.06-0.67), but not with abacavir-based TT (aHR = 0.43, 95% CI = 0.17-1.11). Conversely, in the setting of pre-existing M184V/I, DT showed a trend to increased risk of VF (versus tenofovir-based TT, aHR = 137.50, 95% CI = 4.24-4464.06; versus abacavir-based TT, aHR = 33.88, 95% CI = 1.75-656.47).

CONCLUSIONS

Lamivudine/dolutegravir maintenance DT showed similar efficacy to dolutegravir-based TT; however, past M184V/I may favour VF.

Update and latest advances in antiretroviral therapy

Since the first cases of AIDS appeared in 1981, human immunodeficiency virus type 1 (HIV-1) infection has reached pandemic proportions. Forty years later, research has led to the approval of more than 30 antiretroviral drugs, while combination therapies have turned HIV-1 infection into a chronic, but manageable disease. Still, drug toxicity and acquired and transmitted drug resistance remain as major threats to therapy success. In this review, we provide an overview on currently available anti-HIV drugs and the latest developments in antiretroviral therapy, focused on new antiretroviral agents acting on known and unexploited antiviral targets, prevention therapies aimed to improve available drug combinations, and research on new long-acting therapies, particularly those involving novel drug candidates such as lenacapavir or islatravir.

Real-World Experience with Two-Drug Regimens in HIV-1-Infected Patients Beyond the Indication of Clinical Trials: 48 Weeks' Results

Data on two-drug regimens (2DRs) have shown high efficacy and tolerability in treatment-naive and treatment-experienced HIV-1 patients. Current guidelines recommend 2DRs as alternative to three-drug regimens (3DRs) to reduce long-term drug exposure and costs. Nevertheless, real-world experience with 2DR is limited. This study assessed the use of 2DR in routine clinical practice in a tertiary hospital. A retrospective, observational, descriptive study was performed on the use of dual therapy in adult HIV-1 patients. Individuals on antiretroviral treatment (ART) with dolutegravir plus lamivudine or dolutegravir plus rilpivirine who started 2DR between November 1, 2018, and April 30, 2019, were eligible for our study. Follow-up period was 48 weeks. Overall, 112 patients started 2DR; median age was 51 years and 88.4% were men. Most patients (97.3%) were treatment experienced before dual therapy, with 9.6 ± 8.0 years of prior ART on average. Around 96.4% of patients were virologically suppressed before 2DR. Most common reasons to start dual therapy were treatment simplification (49.5%), avoidance of long-term toxicities (21.1%), and intolerance to previous ART (18.3%). The main regimen used in dual therapy was dolutegravir plus lamivudine (98.2%). Only eight patients discontinued dual therapy; the main reason for discontinuation was toxicity. All patients who did not discontinue 2DR were virologically suppressed at week 48. ART simplification saved €130,117.58 during the study period. In our cohort, dual therapy was mainly used for virologically suppressed patients, before availability of the single-tablet 2DR. Switching to a 2DR may be a key option for treatment simplification and avoidance of long-term toxicities. Furthermore, 2DR could provide a more cost-effective alternative to 3DR.

Deep sequencing analysis of M184V/I mutation at the switch and at the time of virological failure of boosted protease inhibitor plus lamivudine or boosted protease inhibitor maintenance strategy (substudy of the ANRS-MOBIDIP trial)

BACKGROUND

The ANRS12286/MOBIDIP trial showed that boosted protease inhibitor (bPI) plus lamivudine dual therapy was superior to bPI monotherapy as maintenance treatment in subjects with a history of M184V mutation.

OBJECTIVES

We aimed to deep analyse the detection of M184V/I variants at time of switch and at the time of virological failure (VF).

METHODS

Ultra-deep sequencing (UDS) was performed on proviral HIV-DNA at inclusion among 265 patients enrolled in the ANRS 12026/MOBIDIP trial, and on plasma from 31 patients experiencing VF. The proportion of M184V/I variants was described and the association between the M184V/I mutation at 1% of threshold and VF was explored with logistic regression models.

RESULTS

M184V and I mutations were detected in HIV-DNA for 173/252 (69%) and 31/252 (12%) of participants, respectively. Longer duration of first-line treatment, higher plasma viral load at first-line treatment failure and higher baseline HIV-DNA load were associated with the archived M184V. M184I mutation was always associated with a STOP codon, suggesting defective virus. The 48 week estimated probability of remaining free from VF was comparable with or without the M184V/I mutation for dual therapy. At failure, M184V and major PI mutations were detected in 1/17 and 5/15 patients in the bPI arm and in 2/2 and 0/3 in the bPI+lamivudine arm, respectively.

CONCLUSIONS

Using UDS evidenced that archiving of M184V in HIV-DNA is heterogeneous despite past historical M184V in 96% of cases. The antiviral efficacy of lamivudine-based dual therapy regimens is mainly due to the residual lamivudine activity.

Effectiveness of boosted darunavir plus rilpivirine in patients with long-lasting HIV-1 infection: DARIL study

BACKGROUND

The combination of boosted darunavir plus rilpivirine, once daily, could be a convenient, effective and well-tolerated two-drug regimen to achieve HIV suppression in HIV-infected patients.

METHODS

Multicentre, retrospective cohort study in nine hospitals in Spain. All HIV-infected subjects starting boosted darunavir plus rilpivirine were included, irrespective of their viral load (VL). The primary objective was the percentage of patients with VL <50 copies/mL at 48 weeks. Secondary objectives included changes in CD4+ cell count, lipid profile and renal function.

RESULTS

Eighty-one of 84 patients reached Week 48. Fifty-nine (70.2%) patients had VL <50 copies/mL at baseline and the rest had a median VL of 202 (IQR 98-340) copies/mL. Subjects had a median of 21 years of infection with six prior regimens. The main reasons for starting boosted darunavir plus rilpivirine were simplification (44%), kidney or bone toxicity (28.6%) and virological failure (17.9%). Historical genotypes from 47 patients showed 41 (87.2%) patients with NRTI RAMs, 21 (44.7%) with NNRTI RAMs, 12 (25.5%) with primary PI RAMs and 7 (14.9%) with integrase strand transfer inhibitor (INSTI) RAMs. One patient had low-level resistance to boosted darunavir and five patients had some resistance to rilpivirine. At 48 weeks, 71 (87.7%) patients had VL <50 copies/mL. According to undetectable or detectable baseline VL, effectiveness was 91.1% or 80%, respectively. There were four virological failures with no emergence of new RAMs. Three of these patients resuppressed viraemia while maintaining the same regimen.

CONCLUSIONS

The combination of boosted darunavir plus rilpivirine has shown good effectiveness and tolerability in this cohort of pretreated patients with a long-lasting HIV infection, exposure to multiple antiretroviral regimens and prior HIV resistance.

Risks and benefits of reducing the number of drugs to treat HIV-1 infection

Introduction: Despite the efficacy and safety of antiretroviral therapy, new treatment options are needed to address the concerns of patients and physicians regarding long-term toxicities, costs, and convenience of lifelong antiretroviral therapy. To achieve this goal, one strategy is to reduce the number of drugs in the antiretroviral regimen.Areas covered: We review the recent evidence on the efficacy and safety of reduced drug regimens and their potential risks and benefits. There is currently strong evidence showing that some two-drug regimens have a comparable efficacy and short-term safety compared to standard three-drug regimens. The fixed-dose combination of dolutegravir/lamivudine is already an alternative for many treatment-naïve and virologically suppressed HIV-1 infected adults supported by large randomized clinical trials. The co-formulation dolutegravir plus rilpivirine is also a switch strategy for maintenance therapy. Long-acting injectable cabotegravir plus rilpivirine has already regulatory approval, and islatravir plus doravirine is an expected option in the near future. Some two-drug regimens have not been as successful.Expert opinion: Long-term safety issues of these two-drug regimens remain to be determined, but with the overwhelming evidence available in virological control and short-term safety, the potential benefits of some of these two-drug regimens appear to outweigh the risks.

Durable Efficacy of Dolutegravir Plus Lamivudine in Antiretroviral Treatment-Naive Adults With HIV-1 Infection: 96-Week Results From the GEMINI-1 and GEMINI-2 Randomized Clinical Trials

Supplemental Digital Content is Available in the Text.

The 2-drug regimen dolutegravir + lamivudine was noninferior to dolutegravir + tenofovir disoproxil fumarate/emtricitabine in achieving HIV-1 RNA <50 copies/mL in treatment-naive adults in the 48-week primary analysis of the GEMINI trials. We present results from the prespecified 96-week secondary analyses.

Real-World Experience with Dolutegravir-Based Two-Drug Regimens

Background

Dolutegravir-based 2-drug regimens (DTG 2DRs) are now accepted as alternatives to 3-drug regimens for HIV antiretroviral treatment (ART); however, literature on physician drivers for prescribing DTG 2DR is sparse. This study evaluated treatment patterns of DTG 2DR components in clinical practice in the US.

Methods

This was a retrospective chart review in adult patients in care in the US with HIV-1 who received DTG 2DR prior to July 31, 2017, with follow-up until January 30, 2018. Primary objectives of the study were to determine reasons for patients initiating DTG 2DR and to describe the demographics and clinical characteristics. All analyses were descriptive.

Results

Overall, 278 patients received DTG 2DR (male: 70%; mean age: 56 years). Most patients were treatment experienced (98%), with a mean 13.5 years of prior ART. DTG was most commonly paired with darunavir (55%) or rilpivirine (27%). The most common physician-reported reasons for initiating DTG 2DR were treatment simplification/streamlining (30%) and avoidance of potential long-term toxicities (20%). Before starting DTG 2DR, 42% of patients were virologically suppressed; of those, 95% maintained suppression while on DTG 2DR. Of the 50% of patients with detectable viral load before DTG 2DR, 79% achieved and maintained virologic suppression on DTG 2DR during follow-up. There were no virologic data for 8% of patients prior to starting DTG 2DR. Only 15 patients discontinued DTG 2DR, of whom 4 (27%) discontinued due to virologic failure.

Conclusions

Prior to commercial availability of the single-tablet 2DRs, DTG 2DR components were primarily used in treatment-experienced patients for treatment simplification and avoidance of long-term toxicities. Many of these patients achieved and maintained virologic suppression, with low discontinuation rates.

Two-drug vs. three-drug combinations for HIV-1: Do we have enough data to make the switch?

Three-drug combination antiretroviral therapy (ART) became available in 1996, dramatically improving the prognosis of people living with HIV. The clinical benefits of ART are due to the sustained viral load suppression and CD4 T cell gains. Major drawbacks of the first ART regimens were adverse events, and high pill burden, which led to the reduction of drug adherence resulting in frequent treatment discontinuations and the development of drug resistance. Due to increased viral potency of new antiretroviral drugs consideration of a two-drug combination therapy repositioning occurred in an effort to reduce adverse events, drug-drug interactions and cost, while maintaining a sustained antiviral effect. Various combinations of two-drug regimens have been studied, and non-inferiority compared to a three-drug regimen has been shown only for some of them. In addition, a two-drug combination regimen may not be suitable for every patient, especially those who are pregnant, those with tuberculosis or coexisting HBV infection. Furthermore no information has been generated concerning the secondary transmission of HIV from patients who have undetectable plasma viral load on two-drug regimens. Additional studies of two-drug combinations are also necessary to evaluate the debated existence of low viral replication in tissues and on immune activation. While there is no urgent need to routinely switch patients to two-drug combination therapy, due to the availability of drug combinations without significant toxicities, dual regimens represent a suitable option that deserve long-term evaluation before being introduced to clinical practice.

Dolutegravir plus lamivudine for the treatment of HIV-1 infection

Introduction: Recent data on the 2-drug regimen (2DR) with dolutegravir (DTG) plus lamivudine (3TC) have shown high efficacy and tolerability both in treatment-naïve and experienced HIV-positive patients. Current guidelines recommend DTG+3TC 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 about the efficacy, safety, and tolerability of a 2DR with DTG+3TC in naïve and treatment-experienced patients.Expert opinion: Data from clinical trials and from real-life show that DTG+3TC is an effective and safe switch option for the treatment of experienced patients. In treatment-naïve patients, DTG+3TC has shown non-inferiority compared to standard 3-drug regimens but is less effective in severely immunocompromised naïve patients (i.e. with a CD4+ cell count below 200 cell/mm3); furthermore, current guidelines have upgraded this dual regimen to recommended first-line strategy, but indicate that it should not be used without genotypic resistance results. Moreover, this regimen is not feasible for HBV-coinfected individuals and should not be used during pregnancy. Currently, out of 2-drug regimens, DTG+3TC is one of clinicians' preferred option as it requires no pharmacokinetic booster, has a low risk of drug interaction, and does not require food intake.

Development of darunavir over the entire spectrum of HIV infection

Darunavir is the gold standard protease inhibitor in antiretroviral treatment. It has undergone complete development through randomised clinical trials throughout the entire spectrum of HIV infection, with 2 different dosages and clear indications of when to use each one of them. It has been studied in mono, dual and triple therapy. It can also be administered boosted with either ritonavir or cobicistat. The data indicate that it is the antiretroviral with the greatest barrier against resistance development and that it is the drug with the longest residence time bound to its receptor (protease), thus having the longest dissociation time. Its limited impact on selected mutations in the protease by other inhibitors and its high barrier against resistance have resulted in its widespread commercial use being associated with a steady decrease in the mutations circulating in the protease having an impact on its activity. Supplement information: This article is part of a supplement entitled "Co-formulated cobicistat-boosted darunavir, emtricitabine, and tenofovir alafenamide for the treatment of HIV infection", which is sponsored by Janssen.

Lamivudine-based maintenance antiretroviral therapies in patients living with HIV-1 with suppressed HIV RNA: derivation of a predictive score for virological failure

OBJECTIVES

Two-drug antiretroviral regimens based on lamivudine (3TC) plus either a protease inhibitor (PI) or dolutegravir (DTG) are becoming increasingly popular in switch strategies. Our goal was to derive a predictive score for virological failure (VF).

METHODS

We retrospectively analysed data for a cohort of 587 virologically suppressed (HIV RNA < 37 HIV-1 RNA copies/mL), adult (≥ 18 years old) patients starting lamivudine plus either a boosted PI or dolutegravir. Predictors of VF (defined as a single HIV RNA measurement ≥ 1000 copies/mL or two consecutive HIV RNA measurements ≥ 50 copies/mL) were identified using a multivariate Cox regression model. A 'weighted' score was assigned to each variable associated with VF; the discriminative power of the score obtained was expressed as the area under the receiver-operator characteristic curve (ROC-AUC).

RESULTS

During a median 2 years of follow-up time, 35 VFs occurred; predictors of VF were baseline residual HIV RNA between 20 and 36 copies/mL, African ethnicity, ≥ 10 therapeutic lines, the presence of at least one resistance-associated mutation (RAM) for resistance to current drugs (excluding M184V), a non-B viral subtype and a baseline CD4 count < 200 cells/μL. A score of 2 was assigned to non-B viral subtype, 3 to residual viraemia ≥ 20 copies/mL, ≥ 10 previous therapeutic lines and African ethnicity, 4 to baseline CD4 count < 200 cells/μL, and 7 to the presence of at least one RAM (excluding M184V). The ROC-AUC was 0.67 (95% confidence interval 0.57-0.77).

CONCLUSIONS

The presence of at least one RAM, higher residual viraemia and African ethnicity were among the major predictors of VF in our cohort. Studies with larger sample sizes are warranted to improve the predictive value of the derived score.

Efficacy and tolerability of lamivudine plus dolutegravir compared with lamivudine plus boosted PIs in HIV-1 positive individuals with virologic suppression: a retrospective study from the clinical practice

BACKGROUND

Direct comparisons between lamivudine plus bPIs and lamivudine plus dolutegravir as maintenance strategies in virologically-suppressed HIV positive patients are lacking.

METHODS

Time to treatment discontinuation (TD) and virological failure (VF) were compared in a cohort of HIV+ patients on a virologically-effective ART starting lamivudine with either darunavir/r, atazanavir/r or dolutegravir. Changes in laboratory parameters were also evaluated.

RESULTS

Four-hundred-ninety-four patients were analyzed (170 switching to darunavir/r, 141 to atazanavir/r, 183 to dolutegravir): median age was 49 years, with 8 years since ART start. Groups differed for age, HIV-risk factor, time since HIV-diagnosis and on ART, previous therapy and reasons for switching. Estimated proportions free from TD at week 48 and 96 were 79.8 and 48.3% of patients with darunavir/r, 87.0 and 70.9% with atazanavir/r, and 88.2 and 82.6% with dolutegravir, respectively (p < 0.001). Calendar years, HIV-risk factor, higher baseline cholesterol and an InSTI-based previous regimen predicted TD, whereas lamivudine+dolutegravir therapy and previous tenofovir use were protective. VF was the cause of TD in 6/123 cases with darunavir/r, 4/97 with atazanavir/r and 3/21 with dolutegravir. Other main reasons for TD were: toxicity (43.1% with darunavir/r, 39.2% with atazanavir/r, 52.4% with dolutegravir), further simplification (36.6% with darunavir/r, 30.9% with atazanavir/r, 14.3% with dolutegravir). Incidence of VF did not differ among study groups (p = 0.747). No factor could predict VF. Lipid profile improved in the dolutegravir group, whereas renal function improved in the bPIs groups.

CONCLUSIONS

In real practice, a switch to lamivudine+dolutegravir showed similar efficacy but longer durability than a switch to lamivudine+bPIs.