Analysis of drug resistance during HIV RNA viraemia in the MONET trial of darunavir/ritonavir monotherapy

Week 96 efficacy of lopinavir/ritonavir monotherapy in virologically suppressed patients with HIV: a randomized non-inferiority trial (ANRS 140 DREAM)

Background

Sparing of antiretroviral drug classes could reduce the toxicity and cost of maintenance treatment for HIV infection.

Objectives

To evaluate the non-inferiority of efficacy and the safety of lopinavir/ritonavir (r) monotherapy versus a single-tablet regimen of efavirenz, emtricitabine and tenofovir (EFV/FTC/TDF) over 2 years.

Methods

Adults on stable ART with plasma HIV-1 RNA viral load <50 copies/mL for the past 12 months and no documented treatment failure were randomized to receive either lopinavir/r or EFV/FTC/TDF for 2 years. The primary endpoint was the proportion of patients without treatment failure at week 96 (viral load <50 copies/mL at week 96, confirmed at week 98), without study treatment discontinuation, a new AIDS-defining illness, or death.

Results

In the ITT analysis, the primary endpoint was reached by, respectively, 64% and 71% of patients in the lopinavir/r (n = 98) and EFV/FTC/TDF arms (n = 97), yielding a difference of -6.8% (lower limit of the 95% two-sided CI: -19.9%). Sanger and UltraDeep sequencing showed the occurrence of PI mutations in the lopinavir/r arm (n = 4) and of NNRTI and/or NRTI mutations in the EFV/FTC/TDF arm (n = 2). No unexpected serious clinical events occurred.

Conclusions

Lopinavir/r monotherapy cannot be considered non-inferior to EFV/FTC/TDF. PI resistance rarely emerged in the lopinavir/r arm and did not undermine future PI options. Two years of lopinavir/r monotherapy had no deleterious clinical impact when compared with EFV/FTC/TDF.

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.

Effectiveness and safety of dual therapy with rilpivirine and boosted darunavir in treatment-experienced patients with advanced HIV infection: a preliminary 24 week analysis (RIDAR study)

Background

The objective was to analyze the effectiveness and safety of dual therapy with rilpivirine plus boosted-darunavir (RPV + bDRV) in real-life patients.

Methods

Observational, retrospective, multi-center study in HIV+ patients who had received RPV + bDRV for 24 weeks to optimize/simplify their previous antiretroviral treatment. We determined the percentage of patients without virologic failure (2 consecutive viral loads > 50 copies/mL) at 24 weeks of treatment.

Results

The study included 161 patients from 15 hospitals with median age of 49 years; 29.3% had previous AIDS stage and median CD4+ lymphocyte nadir of 170 cells/uL. They had been diagnosed with HIV for a median of 17 years and had received 14 years of ART, with five previous treatment combinations, and 36.6% had a history of virological failure. The reasons for the switch were simplification/optimization (49.7%), toxicity/intolerance (17.4%), or inadequate effectiveness of previous ART (10.6%).

Baseline VL of 50–1000 copies/mL was recorded in 25.5% of the patients. In the“intention-to-treat” analysis at 24 weeks, 87.6% of 161 patients continued the study treatment without virologic failure criteria.

In the “on treatment” analysis (excluding patients who discontinued treatment with dual therapy for any reason other than virologic failure) the efficacy was 94.6% (141/149 patients).

Conclusions

Dual therapy with RPV + DRVb proved to be effective and safe in patients with advanced HIV infection, long exposure to ART, low CD4 nadir, previous virologic failure, and/or history of ineffective ART.

Darunavir/ritonavir monotherapy at a low dose (600/100 mg/day) in HIV-1-infected individuals with suppressed HIV viraemia

Background

Darunavir/ritonavir is a potent PI with a high genetic barrier and pharmacological robustness favourably investigated as monotherapy. Whether darunavir could be dose reduced in the context of monotherapy deserves investigation.

Methods

Patients with HIV suppressed viraemia (plasma viral load <50 copies/mL for 12 months) under ART who had switched to darunavir/ritonavir monotherapy at 600/100 mg/day between 2013 and 2015 were included in this observational 48 week single-centre study. The primary outcome was the proportion of patients with virological success (defined as plasma viral load <50 copies/mL) at week 24. Secondary outcomes included treatment strategy success and resistance.

Results

Thirty-one patients were included with the following baseline characteristics [median (IQR)]: age 52 years (47-57), CD4+ 649 cells/mm3 (463-813), ART duration 16.3 years (9.2-22.3), nadir CD4+ 195 cells/mm3 (144-261) and duration of HIV suppression 7.8 years (4.8-9.7). Prior to switch, ART consisted of PI monotherapy for 28 of 31 patients [darunavir/ritonavir 800/100 mg/day (n = 26), lopinavir/ritonavir (n = 1) and atazanavir/ritonavir (n = 1)] and a triple drug regimen for 3 of 31 patients. Within the 48 weeks of follow-up, no virological failure occurred and two patients discontinued 600/100 mg of darunavir/ritonavir due to side effects at week 16 and 40, leading to a virological suppression rate of 100% (95% CI = 89-100) at weeks 24 and 48. Strategy success rates were 96.8% (95% CI = 83.3-99.9) at week 24 and 93.5% (95% CI = 78.6-99.2) at week 48. Median (IQR) Ctrough values of 800/100 mg of darunavir/ritonavir and 600/100 mg of darunavir/ritonavir were 1537 ng/mL (1286-1724) and 1255 ng/mL (873-2161), respectively.

Conclusions

A lower dose of darunavir/ritonavir used as monotherapy (600/100 mg/day) was highly effective in virologically suppressed HIV-infected patients. Further studies are needed to confirm these data.

Low concordance and resistance mutation emergence in the HIV protease gene among circulating and cell-associated viruses at viral replication episodes during darunavir/ritonavir monotherapy

OBJECTIVE

To assess the changes on the HIV protease gene in plasma and peripheral blood mononuclear cell (PBMC) compartments during viral replication episodes in patients on boosted-darunavir monotherapy (mtDRV/rtv).

METHODS

A prospective study was carried out in which adult HIV-1-infected patients who started mtDRV/rtv after viral suppression for ≥ 6 months with no major darunavir-related resistance mutations were enrolled. Patients with two consecutive plasma HIV RNA measurements >200 HIV-1 RNA copies/mL were considered as having virological failure (VF), while patients with two consecutive plasma HIV RNA measurements >50 copies/mL without meeting the VF criteria were considered to have virological rebound (VR). HIV protease genotypic profiles from plasma and PBMCs were performed at baseline and at VF and VR episodes.

RESULTS

One hundred and fifty patients were included in the study, with overall VF and VR rates of 14% (n=21) and 14.7% (n=22), respectively. No major darunavir resistance mutations were observed in the plasma or PBMC samples. Circulating and cell-associated viruses showed a wild-type protease gene sequence in 54% and 23% of patients, respectively while the remainder patients only harboured minor protease inhibitor-associated mutations. Full concordance between plasma RNA and PBMC DNA protease genotypes was found in 23% of the sequences.

CONCLUSIONS

No darunavir-related mutations were found in patients with VF or VR, either in plasma or in PBMCs; thus, simplification to mtDRV/rtv does not comprise future antiretroviral treatment options.

Boosted protease inhibitor monotherapy in HIV-infected adults: outputs from a pan-European expert panel meeting

While the introduction of combination highly active antiretroviral therapy (HAART) regimens represents an important advance in the management of human immunodeficiency virus (HIV)-infected patients, tolerability can be an issue and the use of several different agents may produce problems. The switch of combination HAART to ritonavir-boosted protease inhibitor (PI) monotherapy may offer the opportunity to maintain antiviral efficacy while reducing treatment complexity and the risks of toxicity. Current European AIDS Clinical Society (EACS) guidelines recognise ritonavir-boosted PI monotherapy with twice-daily lopinavir/ritonavir or once-daily darunavir/ritonavir as a possible option in patients who have intolerance to nucleoside reverse transcriptase inhibitors, or for treatment simplification. Clinical trials data for PI boosted monotherapy are encouraging, showing substantial efficacy in the majority of patients; however, further data are required before this approach can be recommended as a routine treatment. Available data indicate that the most suitable candidates for the use of boosted PI monotherapy are long-term virologically suppressed patients who have demonstrated good adherence to antiretroviral therapy, who do not have chronic hepatitis B, have no history of treatment failure on PIs and are able to tolerate low-dose ritonavir.

Molecular epidemiology of HIV in a cohort of men having sex with men from Istanbul

In Turkey, the first HIV/AIDS case was reported in 1985. Since then the number of persons with HIV infection has increased, HIV is getting a public health problem. The aim of this study was to determine HIV-1 subtype diversity, drug resistance and gag cleavage site mutations among 20 HIV-infected men having sex with men from Istanbul, Turkey. The most prevalent subtype was found to be subtype B (50 %), but also the non-B subtypes A1, C and CRF02_AG, CRF03_AB and CRF06_cpx were found. Resistance-associated mutations were found in 6 patients (30 %) with 2/6 patients being therapy-experienced and 4/6 therapy-naïve at the time-point of analysis. In these patients, the nucleoside reverse transcriptase inhibitor (NRTI)-associated resistance mutations M41L, T215C, V75I, T69N, the non-NRTI associated mutations V106I, E138A, K103N and the protease inhibitor associated mutations Q58E and V82I were detected. Two virus strains also presented Gag cleavage site mutations. With increasing numbers of HIV-infected Turkish patients that require anti-retroviral treatment, HIV-1 drug-resistance testing is strongly recommended in order to choose the most active drug combination for therapy to achieve better clinical outcomes.

Lopinavir/ritonavir monotherapy after 24 weeks of second-line antiretroviral therapy in Africa: a randomized controlled trial (SARA)

BACKGROUND

Boosted protease inhibitor (bPI) monotherapy (bPImono) potentially has substantial cost, safety and operational benefits. It has never been evaluated as second-line antiretroviral therapy (ART) in Africa.

METHODS

After 24 weeks of lopinavir/ritonavir-containing second-line therapy, DART participants were randomized to remain on combination therapy (CT), or change to bPImono maintenance (SARA trial; ISRCTN53817258). Joint primary end points were CD4(+) T-cell changes 24 weeks later and serious adverse events (SAEs); retrospectively assayed viral load (VL) was a secondary end point. Analyses were intention-to-treat.

RESULTS

A total of 192 participants were randomized to CT (n=95) or bPImono (n=97) and followed for median 60 weeks (IQR 45-84). Participants received median 4.0 years (IQR 3.5-4.4) first-line ART. Median CD4(+) T-cell count at first-line failure was 86 cells/mm(3) (47-136), increasing to 245 cells/mm(3) (173-325) after 24-week induction when 77% had VL<50 copies/ml. Overall, 44 (23%) were receiving second-line therapy with bPI and nucleoside reverse transcriptase inhibitors (NRTI) only, and 148 (77%) with bPI plus non-NRTI (NNRTI) with or without NRTI. At 24 weeks after randomization to CT versus bPImono, mean CD4(+) T-cell increase was 42 (CT, n=85) versus 49 cells/mm(3) (bPImono, n=88; adjusted difference 13 [95% CI -15, 43], P=0.37; non-inferior compared with predetermined non-inferiority margin [-33]). Virological suppression was greater for CT versus bPImono (trend P=0.009): 77% (70/91) versus 60% (56/94) were <50 copies/ml, and 5% (5) versus 14% (13) were ≥1,000 copies/ml, respectively. A total of 0 (0%) versus 5 (5%) participants had major protease inhibitor mutations and 3 (3%) versus 0 (0%) new NNRTI/NRTI mutations were detected during follow-up. Two participants (1 CT and 1 bPImono) died >24 weeks after randomization, and 5 (2 CT and 3 bPImono) experienced SAEs (P=0.51).

CONCLUSIONS

bPImono following a 24-week second-line induction was associated with similar CD4(+) T-cell response, but increased low-level viraemia, generally without protease inhibitor resistance. Longer-term trials are needed to provide definitive evidence about effectiveness in Africa.

Darunavir : a nonpeptidic protease inhibitor for antiretroviral-naive and treatment-experienced adults with HIV infection

INTRODUCTION

Darunavir , a nonpeptidic inhibitor of the HIV-1 protease with potent activity against resistant virus, was initially approved by the FDA (2006) and the EMA (2007) for the treatment of antiretroviral-experienced adults, and later for naive adults. Darunavir/ritonavir (600/100 mg twice daily, ideally given with two other active antiretrovirals) demonstrated superior efficacy compared to lopinavir/ritonavir and other protease inhibitors in highly experienced patients. Darunavir/ritonavir (800/100 mg once daily) was demonstrated to be safe and effective for the treatment of naive patients and those with limited darunavir resistance-associated mutations (RAMs). Because darunavir must be coadministered with ritonavir, cytochrome P450 drug-drug interactions can be problematic.

AREAS COVERED

The chemistry, pharmacokinetics, pharmacodynamics, efficacy and safety of darunavir are reviewed in this paper. A PubMed search was conducted using the search terms 'randomized', 'darunavir' and 'efficacy'. Review articles and studies that primarily focused on other drugs were excluded.

EXPERT OPINION

Because darunavir exhibits efficacy against virus with significant protease inhibitor resistance mutations, it is critically important in the treatment of experienced patients, although viral suppression rates may be lower in those with a high baseline viral load or a greater number of cumulative darunavir RAMs. Darunavir/ritonavir is efficacious and well tolerated as a once-daily regimen in naive patients.

Resistant minority species are rarely observed in patients on darunavir/ritonavir monotherapy

OBJECTIVES

To analyse the emergence of resistant viruses in patients failing darunavir monotherapy, including minority species, and to investigate the impact of baseline reverse transcriptase (RT), protease (PR) and gag resistance mutations on virological failure (VF) occurrence.

METHODS

Nine of the 225 HIV-1-infected patients enrolled in the MONOI trial (darunavir/ritonavir monotherapy or darunavir/ritonavir + two nucleoside reverse transcriptase inhibitors in a switch strategy) experienced VF, defined as two plasma HIV-1 viral loads >400 copies/mL at least 2 weeks apart. Among these nine patients with VF, five were in the darunavir/ritonavir monotherapy arm and four were in the darunavir/ritonavir triple therapy arm. Bulk sequences of the PR, RT and gag genes at baseline (on DNA) and at the time of VF (on RNA) were determined for all patients with two viral loads >50 copies/mL at least 2 weeks apart (n = 47). PR and gag gene clonal analysis was performed on plasma samples of the nine patients with VF.

RESULTS

There was no association between mutations in RT, PR and gag genes in DNA and VF occurrence. None of the patients demonstrated selection of darunavir resistance mutations among the 47 patients with a viral load >50 copies/mL at least 2 weeks apart. The virus of one of the nine patients with VF presented minority variants with darunavir resistance mutations at positions 32, 47 and 50. Clonal analysis of the gag region for the nine patients with VF did not show any selection of minority variants.

CONCLUSIONS

In patients with failure on darunavir/ritonavir monotherapy we did not find any selection of darunavir resistance mutations using standard genotype testing. However, the virus of one patient among nine failures presented minority variants plus darunavir resistance mutations.

Long-term efficacy of darunavir/ritonavir monotherapy in patients with HIV-1 viral suppression: week 96 results from the MONOI ANRS 136 study

OBJECTIVES

Long-term results at week 96 are needed to evaluate the capacity of the darunavir/ritonavir monotherapy strategy to maintain a sustained control of the HIV-1 viral load.

METHODS

MONOI is a prospective, open-label, non-inferiority, randomized, 96 week trial comparing darunavir/ritonavir monotherapy versus a darunavir/ritonavir triple-therapy strategy to maintain HIV-1 viral load suppression in HIV-1-infected patients.

CLINICAL TRIAL REGISTRATION

NCT00412551.

RESULTS

From 225 randomized patients, 219 patients reached the 48 week follow-up and 211 reached the 96 week follow-up (106 patients in the darunavir monotherapy arm and 105 in the darunavir triple-therapy arm). Baseline characteristics were well balanced between the two treatment groups. At week 96, in intent-to-treat analysis, 91/103 patients (88%, 95% CI 81-94) allocated to the darunavir/ritonavir monotherapy arm and 87/104 patients (84%, 95% CI 75-90) allocated to the darunavir triple-therapy arm achieved an HIV-1 viral load <50 copies/mL, with no statistical difference between the two groups. Throughout the 96 week follow-up, 66/112 patients (59%, 95% CI 49-68) and 79/113 patients (70%, 95% CI 61-78) consistently had HIV-1 RNA <50 copies/mL with darunavir/ritonavir monotherapy and darunavir/ritonavir triple therapy, respectively.

CONCLUSIONS

The MONOI study establishes darunavir/ritonavir monotherapy as durable and efficacious for maintaining virological suppression in HIV-1 patients. Darunavir/ritonavir monotherapy should be considered as a (tailored) treatment option for standard triple-therapy patients who have had a substantial period of viral suppression.

HIV protease inhibitors: present and future

Antiretroviral therapy offers many options, largely based on the next-generation protease inhibitors (PIs). Early PI-based treatments involve high pill burdens and dosing schedules, and concerns of long-term toxicities are well established. In patients who have already achieved viral suppression, novel agents and strategies should be used to simplify the dosing treatment, reduce adverse events or preserve drug options. In experienced patients, drug escalation between PIs and different associations between classes allow virological suppression to be reached in the majority of patients. Therefore, there is a persistent clinical need for the discovery and development of new protease inhibitors. Several firms are trying to develop new types of PIs that will not be cross-resistant with existing drugs and will not require ritonavir boosting. This article aims to offer an overview on present drug options recommended for treatment in naive and experienced patients, new strategies currently undergoing clinical evaluation and new compounds in the pipeline.