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

Human Immunodeficiency Virus Drug Resistance: 2018 Recommendations of the International Antiviral Society-USA Panel

Background

Contemporary antiretroviral therapies (ART) and management strategies have diminished both human immunodeficiency virus (HIV) treatment failure and the acquired resistance to drugs in resource-rich regions, but transmission of drug-resistant viruses has not similarly decreased. In low- and middle-income regions, ART roll-out has improved outcomes, but has resulted in increasing acquired and transmitted resistances. Our objective was to review resistance to ART drugs and methods to detect it, and to provide updated recommendations for testing and monitoring for drug resistance in HIV-infected individuals.

Methods

A volunteer panel of experts appointed by the International Antiviral (formerly AIDS) Society–USA reviewed relevant peer-reviewed data that were published or presented at scientific conferences. Recommendations were rated according to the strength of the recommendation and quality of the evidence, and reached by full panel consensus.

Results

Resistance testing remains a cornerstone of ART. It is recommended in newly-diagnosed individuals and in patients in whom ART has failed. Testing for transmitted integrase strand-transfer inhibitor resistance is currently not recommended, but this may change as more resistance emerges with widespread use. Sanger-based and next-generation sequencing approaches are each suited for genotypic testing. Testing for minority variants harboring drug resistance may only be considered if treatments depend on a first-generation nonnucleoside analogue reverse transcriptase inhibitor. Different HIV-1 subtypes do not need special considerations regarding resistance testing.

Conclusions

Testing for HIV drug resistance in drug-naive individuals and in patients in whom antiretroviral drugs are failing, and the appreciation of the role of testing, are crucial to the prevention and management of failure of ART.

Darunavir/cobicistat showing similar effectiveness as darunavir/ritonavir monotherapy despite lower trough concentrations

INTRODUCTION

When darunavir (DRV) 800 mg is boosted with 150 mg cobicistat (DRVcobi ), DRV trough concentration (Ctrough ) is about 30% lower as compared to 100 mg ritonavir (DRVrtv ). DRVcobi shows similar virological efficacy as DRVrtv when combined with two nucleos(t)ide analogue reverse-transcriptase inhibitors, but it is unknown whether a lower DRV Ctrough would undermine the effectiveness of DRVcobi when given as monotherapy (mtDRVcobi ).

METHODS

Prospective observational study on virologically suppressed HIV-infected subjects who switched to mtDRVcobi . Virological failure was defined as two consecutive HIV-RNA >200 copies/mL. Efficacy was evaluated by intention-to-treat (ITT) and on-treatment (OT) analyses, and compared with data from a previous cohort of subjects on mtDRVrtv conducted at our centre. Plasma DRV Ctrough was measured using LC-MS/MS.

RESULTS

A total of 234 subjects were enrolled. At week 96, the efficacy rates were 67.8% (CI95 , 61.8 to 73.7) by ITT and 86.9% (CI95 , 78.0 to 87.7) by OT analyses. The corresponding rates in our historical DRVrtv controls were 67.6% (CI95 , 60.0 to 75.2) and 83.6% (CI95 : 77.2 to 90.0). A total of 135 DRV determinations were performed in 83 subjects throughout the follow-up period, with a median plasma DRV Ctrough of 1305 ng/mL (range, 150 to 5895) compared with 1710 ng/mL (range, 200 to 3838) in subjects on monotherapy with DRVrtv (p = 0.05).

CONCLUSIONS

DRV Ctrough was lower in HIV-infected subjects receiving DRVcobi than with DRVrtv . However, this did not appear to influence the efficacy of DRVcobi , when administered as monotherapy.

The Protease Inhibitor Monotherapy Versus Ongoing Triple Therapy (PIVOT) trial: a randomised controlled trial of a protease inhibitor monotherapy strategy for long-term management of human immunodeficiency virus infection

BACKGROUND

Standard-of-care antiretroviral therapy (ART) for human immunodeficiency virus (HIV) infection uses a combination of drugs, until now considered essential to minimise treatment failure and development of drug resistance. Protease inhibitors (PIs) are potent with a high genetic barrier to resistance and have the potential for use as monotherapy after viral load (VL) suppression achieved on combination therapy. However, longer-term resistance and toxicity risks are uncertain.

OBJECTIVE

To compare the effectiveness, toxicity profile and cost-effectiveness of PI monotherapy with those of standard-of-care triple therapy in a pragmatic long-term clinical trial.

DESIGN

Open-label, parallel-group, randomised controlled trial.

SETTING

Forty-three HIV clinical centres in the UK NHS.

PARTICIPANTS

HIV-positive adults taking standard combination ART with a suppressed VL for ≥ 6 months.

INTERVENTIONS

Patients were randomised to maintain ongoing triple therapy (OT) or switch to a strategy of physician-selected ritonavir-boosted PI monotherapy (PI-mono), with prompt return to combination therapy in the event of VL rebound.

MAIN OUTCOME MEASURES

The primary outcome was reduction of future drug options, defined as new intermediate-/high-level resistance to one or more drugs to which the patient's virus was considered to be sensitive at trial entry (non-inferiority comparison, 10% margin). Secondary outcomes included confirmed virological rebound, serious drug- or disease-related complications, total grade 3 or 4 adverse events (AEs), neurocognitive function change, cluster of differentiation 4 (CD4) cell count change, change in health-related quality of life, cardiovascular risk change, health-care costs and health economic analysis.

RESULTS

In total, 587 participants were randomised (77% male, 68% white) to OT (n = 291) or PI-mono (n = 296) and followed for a median of 44 months, of whom 2.7% withdrew/were lost to follow-up. One or more episodes of confirmed VL rebound were observed in eight patients (Kaplan-Meier estimate 3.2%) in the OT group and 95 patients (35.0%) in the PI-mono group [absolute risk difference 31.8%, 95% confidence interval (CI) 24.6% to 39.0%; p < 0.001]. PI-mono patients who changed to ART after VL rebound all resuppressed (median 3.5 weeks). The proportions with loss of a future drug option at 3 years were 0.7% in the OT group and 2.1% in the PI-mono group (difference 1.4%, (95% CI -0.4% to 3.4%); non-inferiority demonstrated). There were no significant differences in serious disease complications between groups or in the frequency of grade 3 or 4 clinical AEs (16.8% OT group vs. 22% PI-mono group; absolute risk difference 5.1%, 95% CI -1.3% to 11.5%; p = 0.12). Overall, the PI-mono strategy was shown to be cost-effective compared with OT under most scenarios explored. PI-mono was cost saving because of the large savings in ART drug costs while being no less effective in terms of quality-adjusted life-years in the within-trial analysis and only marginally less effective when extrapolated to lifetime outcomes.

CONCLUSIONS

PI monotherapy, with prompt reintroduction of combination therapy for VL rebound, was non-inferior to combination therapy in preserving future treatment options and is an acceptable and cost-effective alternative for long-term management of HIV infection.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN04857074.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 21. See the NIHR Journals Library website for further project information.

HIV-1 DNA dynamics and variations in HIV-1 DNA protease and reverse transcriptase sequences in multidrug-resistant patients during successful raltegravir-based therapy

There is limited information on the variations of HIV-1 DNA mutation profile in reverse transcriptase (RT) and protease (PR) genes during suppressive antiretroviral treatment (plasma HIV-1 RNA continuously <50 copies/ml) with raltegravir (RAL)-based regimens in patients with baseline RT/PR resistant HIV. Twelve multidrug resistant (RT: 12/12, PR: 8/12) HIV-infected patients were followed during effectively suppressive RAL-based therapy. Total and integrated HIV-1 DNA were assessed by real time PCR at baseline and every 6 months. Ultrasensitive (threshold: 2.5 copies/ml) plasma HIV-1 RNA and genotypic analysis of RT and PR in proviral DNA were performed at baseline and at 24 months. Half of the patients had full viral suppression (plasma HIV-RNA < 2.5 copies/ml) at month 12. Total HIV-1 DNA declined significantly after 12 months of therapy (from 249.2 to 145.7 copies/10⁶ cells, P = 0.023), and remained stable until 24 months, when total HIV-1 DNA levels raised, concomitantly with a less stringent suppression of HIV-1 RNA (81.8% of patients with >2.5 copies/ml). Integrated HIV-1 DNA did not show fluctuations during the study period. Sequencing of the PR and RT regions from HIV-1 DNA revealed changes in the resistance mutation profile in five patients. Total HIV-1 DNA declined after the introduction of RAL-based therapy, with a rebound after 2 years. No changes were observed in levels of integrated DNA, suggesting limited effect on archived HIV. The RT and PR sequence changes in archived HIV-1 DNA suggest that variation of the mutation profile can occur even in the absence of detectable HIV-1 RNA. J. Med. Virol. 88:2115-2124, 2016. © 2016 Wiley Periodicals, Inc.