Factors associated with virological rebound in HIV-infected patients receiving protease inhibitor monotherapy

Use of rilpivirine in HIV-1-infected individuals in routine clinical practice from 2012 to 2017 in France

OBJECTIVES

We assessed virological outcomes of rilpivirine use in France from 2012 to 2017, in three groups of people living with HIV (PLHIV): (i) antiretroviral (ARV)-naive PLHIV; (ii) ARV-experienced PLHIV switching to rilpivirine while failing therapy; and (iii) ARV-experienced PLHIV switching to rilpivirine while virologically controlled.

METHODS

Virological success (VS) was defined as a plasma HIV-1 viral load (VL) <50 copies/mL and virological failure (VF) as two consecutive VL >50 copies/mL or one VL >50 copies/mL followed by a treatment switch prior to the next VL measurement. The cumulative incidence of VS was assessed considering rilpivirine discontinuation, loss to follow-up and death as competing risks, while estimates of cumulative incidence of VF accounted for loss to follow-up and death.

RESULTS

Among the 2166 ARV-naive PLHIV initiating rilpivirine, the 4 year cumulative incidence of VS was 91.0% and was associated with baseline VL. Among the 2125 ARV-experienced PLHIV switching to rilpivirine while failing therapy, the 4 year cumulative incidence of VS was 82.5% and was associated with lower VL, higher CD4 and less than three prior ARVs. Among the 11 828 ARV-experienced PLHIV switching to rilpivirine while virologically controlled, the 4 year cumulative incidence of VF was 9.6%. The risk of VF was lower among MSM, for PLHIV with CD4 ≥ 500 cell/mm3, without a prior AIDS event, or with a longer VL suppression at baseline.

CONCLUSIONS

Rilpivirine-containing regimens yielded high rates of viral suppression in most participants, while it was ineffective when used outside the marketing authorization in naive participants.

Long-term follow-up of HIV-infected patients on dolutegravir monotherapy

BACKGROUND

In recent years, dolutegravir monotherapy has been explored as a drug-reduced regimen for HIV patients.

METHODS

This was a retrospective observational study, including patients virologically suppressed for ≥6 months, without previous virological failure (VF) under integrase inhibitors (INIs), who had been switched to dolutegravir monotherapy (50 mg/day). The primary aim was to report the proportion of VF at week 48 (W48) and week 96 (W96) of dolutegravir monotherapy. The evolution from baseline to W48 of residual viraemia on ultra-deep sequencing and HIV DNA was also evaluated.

RESULTS

Sixty-one patients were included. Prior to switching to dolutegravir monotherapy, they had a median (IQR) of 15.4 (6.5-19.9) years of antiretroviral exposure, 5.8 (3.2-10.3) years of viral suppression and 687 (461-848) CD4+ cells/mm3. They remained on dolutegravir monotherapy for a median (IQR) of 100 (29-148) weeks. Forty-two out of 61 patients (68.9%) reached W48 and 32 out of 61 patients (52.5%) reached W96. VF occurred in three patients, with the emergence of INI resistance. VF occurred before W24 and in patients pre-exposed to INIs. At W48, the probability of VF (Kaplan-Meier analysis) was 5.6% (95% CI = 1.8%-16.4%). The same result was obtained at W96. Detectable residual viraemia did not increase and median HIV DNA did not change significantly (2.4 log/106 cells at baseline and 2.3 log/106 cells at W48). Dolutegravir plasma concentration was above the IC90 in 41/41 samples, from 22 patients.

CONCLUSIONS

Long-term follow-up showed a low risk of VF under dolutegravir monotherapy, in a selected population of patients with previous long-term virological suppression and low HIV reservoir.

Use of darunavir in HIV-1-infected individuals in routine clinical practice from 2012 to 2016 in France

OBJECTIVES

We assessed virological outcomes of darunavir use in France from 2012 to 2016, in three groups of people living with HIV (PLHIV): (i) antiretroviral (ARV)-naive PLHIV; (ii) ARV-experienced PLHIV switching to darunavir while failing therapy; and (iii) ARV-experienced PLHIV switching to darunavir while virologically controlled.

METHODS

Virological success (VS) was defined as a plasma HIV-1 viral load (VL) <50 copies/mL and virological failure (VF) as two consecutive VL >50 copies/mL or one VL >50 copies/mL followed by a treatment switch prior to the next VL measurement. The cumulative incidence of VS was assessed considering darunavir discontinuation, loss to follow-up and death as competing risks, while estimates of cumulative incidence of VF accounted for loss to follow-up and death.

RESULTS

Among the 3235 ARV-naive PLHIV initiating darunavir, the 4 year cumulative incidence of VS was 80.9% and was associated with lower VL and higher CD4 cell counts. Among the 3485 ARV-experienced PLHIV switching to darunavir while failing therapy, the 4 year cumulative incidence of VS was 82.2% and was associated with lower VL. Among the 3005 ARV-experienced PLHIV switching to darunavir while virologically controlled, the 4 year cumulative incidence of VF was 12.6%. The risk of VF was higher with darunavir monotherapy [subdistribution hazard ratio (sHR)=1.67, 95% CI 1.15-2.42] while no difference was observed with dual therapy (sHR = 1.00, 95% CI 0.71-1.42) relative to triple therapy or more.

CONCLUSIONS

Darunavir-containing regimens yielded similarly high rates of viral suppression in PLHIV whether they were ARV naive or ARV experienced switching to darunavir while failing therapy, or of maintaining VS in ARV-experienced PLHIV switching to darunavir while virologically controlled.

An apparent paradox: resistance mutations in HIV-1 DNA predict improved virological responses to antiretroviral therapy

BACKGROUND

In sub-Saharan Africa, detecting resistance-associated mutations (RAMs) at failure of first-line ART with two NRTIs plus an NNRTI predicts improved virological responses to second-line therapy with two NRTIs plus a ritonavir-boosted PI (PI/r). This indicates residual NRTI activity in the presence of RAMs, although additional factors may contribute to the effect.

OBJECTIVES

The aim of this study was to investigate the influence of pre-existing RAMs on the outcomes of maintenance monotherapy with ritonavir-boosted darunavir within a randomized trial in Cameroon.

METHODS

RAMs were detected in HIV-1 DNA using PBMCs collected at initiation of darunavir/ritonavir monotherapy. Adherence was assessed by pill count and visual analogue scale (VAS). Predictors of virological failure (confirmed or last available viral load >400 copies/mL) were explored by logistic regression analysis. Trial name = MANET (NCT02155101).

RESULTS

After NNRTI-based therapy, participants (n = 81) had received PI/r-based therapy for a median of 3.2 years and had a confirmed viral load <60 copies/mL and a median CD4 count of 466 cells/mm3. NRTI and NNRTI RAMs were detected in 39/60 (65.0%) and 41/60 (68.3%) HIV-1 DNA sequences, respectively. Over 48 weeks of monotherapy, 16/81 (19.8%) patients experienced virological failure. After adjusting for age, HIV-1 DNA load, adherence by VAS and RAM status, virological failure was less likely with higher VAS-measured adherence (adjusted OR 0.04, 95% CI 0.01-0.37; P = 0.004) and detectable HIV-1 DNA RAMs (adjusted OR 0.15, 95% CI 0.03-0.82; P = 0.028).

CONCLUSIONS

Pre-existing NRTI and NNRTI RAMs are associated with improved virological responses to NRTI-sparing ART in sub-Saharan Africa, indicating a predictive effect that is independent of residual NRTI activity.

Exploration of Reduced Doses and Short-Cycle Therapy for Darunavir/Cobicistat in Patients with HIV Using Population Pharmacokinetic Modeling and Simulations

BACKGROUND AND OBJECTIVES

Protease inhibitors such as darunavir are an important therapeutic option in the anti-human immunodeficiency virus arsenal. Current dosage guidelines recommend using cobicistat- or ritonavir-boosted darunavir 800 mg every 24 h (q24h) in protease inhibitor-naïve patients, or ritonavir-boosted darunavir 600 mg q12h in experienced patients. However, darunavir displays a large, poorly characterized, inter-individual pharmacokinetic variability. The objectives of this study were to investigate the pharmacokinetics of darunavir and to elucidate the sources of its inter-individual variability using population pharmacokinetic modeling. Then, to determine the appropriateness of current treatment guidelines and the feasibility of alternative dosing regimens in a representative cohort of adult patients using simulations.

METHODS

Sparse pharmacokinetic samples were collected in 127 patients with human immunodeficiency virus type 1 infection, then supplemented with rich sampling data from a subset of 12 individuals. Data were analyzed using the nonlinear mixed-effects modeling software NONMEM. The effect of reduced doses (600 mg q24h and 400 mg q24h) or reduced frequency of administration (800 mg q24h for 5 days followed by 2 days of treatment interruption) was simulated.

RESULTS

Our model adequately described the pharmacokinetics of darunavir. Predictors of individual exposure were CYP3A5*3 and SLCO3A1 rs8027174 genotypes, sex, and alpha-1 acid glycoprotein level. No relationship was apparent between darunavir area under the curve and treatment efficacy or safety. For reduced dose regimens, darunavir concentrations remained above the protein binding-corrected EC₅₀ in the majority of subjects. More stringent pharmacokinetic targets were not reached in a significant proportion of patients.

CONCLUSIONS

These results add to the growing body of evidence that darunavir-based therapy could be simplified to reduce costs and toxicity, as well as to improve patient compliance. However, the heterogeneity in pharmacokinetic response should be considered when assessing whether individual patients could benefit from a particular regimen, for instance through the use of population pharmacokinetic models.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03101644, date of registration: 5 April, 2017.

Genital secretion HIV RNA shedding in HIV-positive patients on ritonavir-boosted protease inhibitor monotherapy or standard combination ART: a cross-sectional sub-study from the PIVOT Trial

BACKGROUND

Protease inhibitors (PI) have relatively low penetration into the genital tract, raising concerns about the potential for genital HIV RNA shedding in patients taking PI-based regimens, particularly PI monotherapy (PI-mono).

METHODS

We measured HIV RNA and PI drug concentrations in samples of semen, cervico-vaginal and rectal mucosa secretions, and plasma in patients after 48-96 weeks on PI-mono or standard triple therapy.

RESULTS

A total of 85 participants were recruited. Of the 43 participants on PI-mono (70% on darunavir [DRV]/ritonavir [r]), 3 had detectable virus in semen or vaginal secretions (all below quantification limit), and none in rectal mucosa or plasma. Among those taking triple therapy, five had detectable virus in semen or vaginal secretions (HIV RNA >50 copies/ml in one), none in rectal mucosa and one in plasma. The median (IQR) concentration of DRV and atazanavir in semen (659.7 [339-1,089] and 128.8 [63-368] ng/ml, respectively) and cervico-vaginal samples (2,768 [312-7,879] and 1,836 [359-3,314] ng/ml, respectively) exceeded their protein adjusted median inhibition concentration (MIC₅₀). DRV concentration in rectal secretions showed higher variability compared with concentration in the other sites, with particularly high rectal secretion/blood ratios (median 8.4, IQR 2.6-68.7:1).

CONCLUSIONS

We found no substantive evidence of HIV shedding in patients taking PI-mono, suggesting that PIs provide adequate control of virus in the genital compartment and are unlikely to lead to ongoing sexual transmission.

Ultrasensitive Human Immunodeficiency Virus Type 1 Viral Load as a Marker of Treatment Choice for Simplification Strategies

Background

Using 3 randomized Protease inhibitor (PI) monotherapy studies: Kalesolo, Dream and Monoi, we performed a pooled-analysis. Our objective was to determine in PI monotherapy and standard tritherapy: 1) distribution of ultrasensitive viral load (USVL) at week 96 (W96); 2) factors associated with virological failure (VF) at W96 and 3) factors associated with USVL<1 copy at W96.

Methods

VF was defined as 2 consecutive measurements of Human Immunodeficiency Virus Type 1 RNA viral load>50 copies/mL and analysed in Intention-To-Treat. A logistic model was used to investigate which variables were predictive of a VF and Fisher test to investigate differences in USVL at W96.

Results

Among 609 patients, 73% were male with median age of 44.4 years (IQR 39.8-52.1), baseline CD4/CD8 ratio was 0.8 (IQR 0.6-1.10), baseline CD4 was 564.5/mm3 (IQR 422-707) and 59% presented a baseline USVL<1 copy/mL. At W96, the proportion of USVL<1 copy/mL was significantly different between PI monotherapy and standard tritherapy in pooled-analysis (65% versus 74%; p=0.04). Overall, baseline USVL<1copy/mL, tritherapy and to be a female were associated with USVL<1 copy/mL at W96 (p<0.0001, p=0.049 and p=0.006). In PI monotherapy receiving DRV/r was associated with USVL<1 copy/mL at W96 (p=0.003). Factors associated to virological succes at W96 were higher baseline CD4 (p=0.034) and baseline USVL<1 copy/mL (p=0.0005).

Conclusion

Pooled-analysis of 3 PI monotherapy trials showed better efficacy of tritherapy in terms of USVL at W96. Furthermore regarding USVL at W96, to receive LPV/r seems to be more deleterious than DRV/r. Baseline USVL impacts VF at W96 more specifically in tritherapy arm.

Clinical Trials Registration

NCT00421551, NCT00946595, and NCT00140751.

Impact of intensification with raltegravir on HIV-1-infected individuals receiving monotherapy with boosted PIs

Background

Monotherapy with ritonavir-boosted PIs (PI/r) has been used to simplify treatment of HIV-1-infected patients. In previous studies raltegravir intensification evidenced ongoing viral replication and reduced T cell activation, preferentially in subjects receiving PI-based triple ART. However, data about low-level viral replication and its consequences in patients receiving PI/r monotherapy are scarce.

Methods

We evaluated the impact of 24 weeks of intensification with raltegravir on markers of viral persistence, cellular immune activation and inflammation biomarkers in 33 patients receiving maintenance PI/r monotherapy with darunavir or lopinavir boosted with ritonavir. ClinicalTrials.gov identifier: NCT01480713.

Results

The addition of raltegravir to PI/r monotherapy resulted in a transient increase in 2-LTR (long-terminal repeat) circles in a significant proportion of participants, along with decreases in CD8+ T cell activation levels and a temporary increase in the expression of the exhaustion marker CTLA-4 in peripheral T lymphocytes. Intensification with raltegravir also reduced the number of samples with intermediate levels of residual viraemia (10–60 HIV-1 RNA copies/mL) compared with samples taken during PI/r monotherapy. However, there were no changes in cell-associated HIV-1 DNA in peripheral CD4+ T cells or soluble inflammatory biomarkers (CD14, IP-10, IL-6, C-reactive protein and D-dimer).

Conclusions

Intensification of PI/r monotherapy with raltegravir revealed persistent low-level viral replication and reduced residual viraemia in some patients during long-term PI/r monotherapy. The concomitant change in T cell phenotype suggests an association between active viral production and T cell activation. These results contribute to understanding the lower efficacy rates of PI/r monotherapies compared with triple therapies in clinical trials.

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.

Next generation sequencing of HIV-1 protease in the PIVOT trial of protease inhibitor monotherapy

•

Next generation sequencing (NGS) was performed on patients on PI monotherapy.

•

It revealed previously unidentified minority variant protease mutations in 3 samples.

•

These mutations do not predict clinically important phenotypic resistance.

Background

The PIVOT trial examined whether patients with suppressed viral load on combination antiretroviral therapy could be safely switched long-term to ritonavir-boosted protease inhibitor (PI) monotherapy. The main trial publication reported that only one of 296 patients allocated to PI monotherapy experienced a loss of drug options due to protease mutations (identified by local Sanger sequencing resistance tests) likely selected by study drug.

Objectives

To assess if we had missed low frequency mutations, using a more sensitive methodology.

Study design

We performed next generation sequencing (NGS) on all available frozen plasma samples with VL >1000 copies/ml from patients who were randomised to PI monotherapy. Assays were performed at Public Health England laboratories using a previously described method.

Median coverage depth was 76,000 and the threshold for detection of minority variants was 2%. Drug susceptibility was predicted using the Stanford HIVdb algorithm.

Results

17 of 26 potential samples, all from different patients, were identified and successfully tested. The median viral load was 6780 copies/ml and the median time since randomisation was 43 weeks. NGS revealed previously unidentified minority variant protease mutations (G73D, I54T, L89V) in three samples, at frequencies ranging between 2% and 10%. None of these mutations predicted intermediate or high level resistance, the trial primary outcome.

Discussion

This report adds to the body of evidence that ritonavir-boosted PI monotherapy, when used as a switch strategy with prompt detection of viral load rebound and early re-introduction of combination therapy, rarely leads to the development of clinically important protease resistance mutations.

Treatment Outcomes of Third-line Antiretroviral Regimens in HIV-infected Thai Adolescents

BACKGROUND

Efficacy and safety data of third-line antiretroviral (ARV) regimens in adolescents are limited.

METHODOLOGY

This study enrolled HIV-infected Thais who were treated with third-line regimens consisting of darunavir/ritonavir (DRV/r), etravirine (ETR), tipranavir/ritonavir or raltegravir.

RESULTS

Fifty-four adolescents 2-17 years of age were enrolled from 8 sites and followed for 48 weeks. Reasons for switch were second-line failure (n = 44) and toxicity to second-line regimens (n = 10). At switching to third-line ARV, the median age (interquartile range) was 14.3 (12.4-15.4) years. Genotypes at time of second-line failure (n = 44) were M184V (77%), ≥4 thymidine analogue mutations (25%), non-nucleoside reverse transcriptase inhibitor-resistant associated mutation (RAM) (80%), ETR-RAM score ≥4 (14%), any lopinavir-RAM (59%) and ≥1 major DRV-RAM (41%). The third-line regimens had a median of 4 (min-max, 4-6) drugs and included ETR/DRV/r (43%), DRV/r (33%), ETR (17%), tipranavir/ritonavir (2%) or raltegravir/DRV/r/ (4%). The median CD4 (interquartile range) increased from 16% (12-21) at third-line switch to 21% (18-25) and 410 (172-682) to 607 (428-742) cells/mm at 48 weeks (P < 0.001). HIV RNA declined from 3.9 (2.9-4.9) to 1.6 (1.6-3.0) log10 copies/mL (P < 0.001) and 33/50 (66%) had levels <50 copies/mL at 48 weeks. Seventeen (31%) had HIV-RNA ≥1000 copies/mL; about half due to poor adherence; genotyping in 13 of these adolescents revealed ETR-RAM score ≥4 in 2 (15%) and ≥1 major DRV-RAM in 7 (54%).

CONCLUSIONS

Third-line ARV therapy was well tolerated and resulted in virologic suppression in 70% of adolescents at 1 year. Poor adherence and limited ARV options are major problems in the long-term management of adolescents with HIV.

Durability of viral suppression with first-line antiretroviral therapy in patients with HIV in the UK: an observational cohort study

BACKGROUND

The length of time that people with HIV on antiretroviral therapy (ART) with viral load suppression will be able to continue before developing viral rebound is unknown. We aimed to investigate the rate of first viral rebound in people that have achieved initial suppression with ART, to determine factors associated with viral rebound, and to use these estimates to predict long-term durability of viral suppression.

METHODS

The UK Collaborative HIV Cohort (UK CHIC) Study is an ongoing multicentre cohort study that brings together in a standardised format data on people with HIV attending clinics around the UK. We included participants who started ART with three or more drugs and who had achieved viral suppression (≤50 copies per mL) by 9 months after the start of ART (baseline). Viral rebound was defined as the first single viral load of more than 200 copies per mL or treatment interruption (for ≥1 month). We investigated factors associated with viral rebound with Poisson regression. These results were used to calculate the rate of viral rebound according to several key factors, including age, calendar year at start of ART, and time since baseline.

RESULTS

Of the 16 101 people included, 4519 had a first viral rebound over 58 038 person-years (7·8 per 100 person-years, 95% CI 7·6-8·0). Of the 4519 viral rebounds, 3105 (69%) were defined by measurement of a single viral load of more than 200 copies per mL, and 1414 (31%) by a documented treatment interruption. The rate of first viral rebound declined substantially over time until 7 years from baseline. The other factors associated with viral rebound were current age at follow-up and calendar year at ART initiation (p<0·0001) and HIV risk group (p<0·0001); higher pre-ART CD4 count (p=0·0008) and pre-ART viral load (p=0·0003) were associated with viral rebound in the multivariate analysis only. For 1322 (29%) of the 3105 people with observed viral rebound, the next viral load value after rebound was 50 copies per mL or less with no regimen change. For HIV-positive men who have sex with men, our estimates suggest that the probability of first viral rebound reaches a plateau of 1·4% per year after 45 years of age, and 1·0% when accounting for the fact that 29% of viral rebounds are temporary elevations.

INTERPRETATION

A substantial proportion of people on ART will not have viral rebound over their lifetime, which has implications for people with HIV and the planning of future drug development.

FUNDING

UK Medical Research Council.

Considerations and guidance in designing equity-relevant clinical trials

Health research has documented disparities in health and health outcomes within and between populations. When these disparities are unfair and avoidable they may be referred to as health inequities. Few trials attend to factors related to health inequities, and there is limited understanding about how to build consideration of health inequities into trials. Due consideration of health inequities is important to inform the design, conduct and reporting of trials so that research can build evidence to more effectively address health inequities and importantly, ensure that inequities are not aggravated. In this paper, we discuss approaches to integrating health equity-considerations in randomized trials by using the PROGRESS Plus framework (Place of residence, Race/ethnicity/culture/language, Occupation, Gender, Religion, Education, Socio-economic status, Social capital and "Plus" that includes other context specific factors) and cover: (i) formulation of research questions, (ii) two specific scenarios relevant to trials about health equity and (iii) describe how the PROGRESS Plus characteristics may influence trial design, conduct and analyses. This guidance is intended to support trialists designing equity-relevant trials and lead to better design, conduct, analyses and reporting, by addressing two main issues: how to avoid aggravating inequity among research participants and how to produce information that is useful to decision-makers who are concerned with health inequities.

How to win the HIV-1 drug resistance hurdle race: running faster or jumping higher?

Infections by the human immunodeficiency virus type 1 (HIV-1), the causative agent of the acquired immunodeficiency syndrome (AIDS), are still totaling an appalling 36.7 millions worldwide, with 1.1 million AIDS deaths/year and a similar number of yearly new infections. All this, in spite of the discovery of HIV-1 as the AIDS etiological agent more than 30 years ago and the introduction of an effective combinatorial antiretroviral therapy (cART), able to control disease progression, more than 20 years ago. Although very effective, current cART is plagued by the emergence of drug-resistant viral variants and most of the efforts in the development of novel direct-acting antiviral agents (DAAs) against HIV-1 have been devoted toward the fighting of resistance. In this review, rather than providing a detailed listing of all the drugs and the corresponding resistance mutations, we aim, through relevant examples, at presenting to the general reader the conceptual shift in the approaches that are being taken to overcome the viral resistance hurdle. From the classic 'running faster' strategy, based on the development of novel DAAs active against the mutant viruses selected by the previous drugs and/or presenting to the virus a high genetic barrier toward the development of resilience, to a 'jumping higher' approach, which looks at the cell, rather than the virus, as a source of valuable drug targets, in order to make the cellular environment non-permissive toward the replication of both wild-type and mutated viruses.

Evaluation of cerebrospinal fluid virological escape in patients on long-term protease inhibitor monotherapy

BACKGROUND

A strategy of protease inhibitor (PI) monotherapy with re-introduction of triple therapy in those who rebound has been shown to be a safe and effective treatment simplification approach for long-term management. We sought evidence for cerebrospinal fluid (CSF) virological escape in patients on long-term PI monotherapy.

METHODS

We performed lumbar puncture in asymptomatic participants with suppressed plasma HIV RNA after 96 weeks on the PI monotherapy arm (PI-mono) of the PIVOT trial. We also report CSF HIV RNA concentration in trial participants who were investigated for neurological/neurocognitive symptoms during the trial regardless of study arm allocation.

RESULTS

All 11 asymptomatic participants on PI-mono who were tested had undetectable CSF HIV RNA at week 96. One of the three symptomatic participants on PI-mono had CSF HIV RNA of 1,895 copies/ml (undetectable in plasma) and neither of two symptomatic participants on triple therapy had CSF HIV RNA detected.

CONCLUSIONS

CSF virological escape appears rare in asymptomatic patients on PI monotherapy and may not warrant routine CSF monitoring, but patients with symptoms merit more concern.

Refining criteria for selecting candidates for a safe lopinavir/ritonavir or darunavir/ritonavir monotherapy in HIV-infected virologically suppressed patients

Objective

The primary objective of this study was to estimate the incidence of treatment failure (TF) to protease inhibitor monotherapies (PI/r-MT) with lopinavir/ritonavir (LPV/r) or darunavir/ritonavir (DRV/r).

Design

A multicenter cohort of HIV-infected patients with viral load (VL) ≤50 copies/mL, who underwent a switch from any triple combination therapy to PI/r-MT with either LPV/r or DRV/r.

Methods

VL was assessed in each center according to local procedures. Residual viremia was defined by any HIV-RNA value detectable below 50 copies/mL by a Real-Time PCR method. Standard survival analysis was used to estimate the rate of TF (defined by virological failure or interruption of monotherapy or reintroduction of combination therapy). A multivariable Cox regression analysis with automatic stepwise procedures was used to identify factors independently associated with TF among nadir and baseline CD4+ counts, residual viremia, time spent with <50 HIV-RNA copies/mL before switch, history of virological failure, HCV co-infection, being on a PI/r and hemoglobin concentrations at baseline.

Results

Six hundred ninety patients fulfilled the inclusion criteria and were included in this analysis. Their median follow-up was 20 (10–37) months. By month 36, TF occurred in 176 (30.2%; 95% CI:25.9–34.5) patients. Only CD4+ nadir counts (adjusted hazard ratio [aHR] = 2.03 [95% CI: 1.35, 3.07] for counts ≤100 vs. >100 cells/μL) and residual viremia (aHR = 1.48 [95% CI: 1.01–2.17] vs. undetectable VL) were independently associated to TF.

Conclusions

Residual viremia and nadir CD4+ counts <100 cells/μL should be regarded as the main factors to be taken into account before considering switching to a PI/r-MT.