Predicting Factors of Plasma HIV RNA Undetectability after Switching to Co-Formulated Bictegravir, Emtricitabine, and Tenofovir Alafenamide in Experienced HIV-1 Patients: A Multicenter Study

Switching to bictegravir, emtricitabine, and tenofovir alafenamide (BIC/FTC/TAF) from other antiretroviral regimens is safe and effective for virologically suppressed people living with HIV (PLWH). The term virological suppression includes both low but detectable HIV viremia and undetectable HIV viremia, and the latter is possibly associated with a lower immune activation state. Herein, we describe a 24-month follow-up of experienced PLWH with plasma HIV RNA undetectable or detectable < 50 copies/ml switching to BIC/FTC/TAF. A previous 12-month monitoring was available, and the factors correlated with treatment efficacy. This retrospective multicenter study included PLWH who switched to BIC/FTC/TAF in the period of 2019-2022, and who were HBsAg and HCV RNA negative. The follow-up study times were 6 (T6), 12 (T12), 18 (T18), and 24 (T24) months after the switch (T0). Survival analysis with multiple-failure-per-subject design, Kaplan-Meier survival estimates, multivariate analysis of variance, multilevel linear regression, and a hierarchical ordered logistic model were applied. A total of 329 PLWH had plasma HIV RNA which was either undetectable or detectable at <50 copies/mL at T0, and 197 responded to all inclusion criteria: M/F 140/57; the median CD4+ cell count was 677 cells/mm3; and HIV RNA at T0 was undetectable in 108 patients. Most of the 197 patients (122, 61.9%) were on a previous INSTI-based regimen. HIV RNA undetectability was more frequent at each follow-up point in patients with HIV RNA that was undetectable at T0, and it showed a higher frequency throughout the follow-up period in patients with always-undetectable HIV RNA in the 12 months before the switch. A higher nadir CD4 cell count had a predictive role, and HBcAb positivity had no influence. In conclusion, the switch could be programmed and possibly delayed on a case-by-case basis in order to achieve persistent plasma HIV RNA undetectability. Undiagnosed loss of HBcAb has no detrimental consequences on the response to BIC/FTC/TAF.

Non-nucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy is associated with lower cell-associated HIV RNA and DNA levels as compared with therapy based on protease inhibitors

Background:

It remains unclear whether combination antiretroviral therapy (ART) regimens differ in their ability to fully suppress human immunodeficiency virus (HIV) replication. Here, we report the results of two cross-sectional studies that compared levels of cell-associated (CA) HIV markers between individuals receiving suppressive ART containing either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI).

Methods:

CA HIV unspliced RNA and total HIV DNA were quantified in two cohorts (n = 100, n = 124) of individuals treated with triple ART regimens consisting of two nucleoside reverse transcriptase inhibitors (NRTIs) plus either an NNRTI or a PI. To compare CA HIV RNA and DNA levels between the regimens, we built multivariable models adjusting for age, gender, current and nadir CD4⁺ count, plasma viral load zenith, duration of virological suppression, NRTI backbone composition, low-level plasma HIV RNA detectability, and electronically measured adherence to ART.

Results:

In both cohorts, levels of CA HIV RNA and DNA strongly correlated (rho = 0.70 and rho = 0.54) and both markers were lower in NNRTI-treated than in PI-treated individuals. In the multivariable analysis, CA RNA in both cohorts remained significantly reduced in NNRTI-treated individuals (p_adj = 0.02 in both cohorts), with a similar but weaker association between the ART regimen and total HIV DNA (p_adj = 0.048 and p_adj = 0.10). No differences in CA HIV RNA or DNA levels were observed between individual NNRTIs or individual PIs, but CA HIV RNA was lower in individuals treated with either nevirapine or efavirenz, compared to PI-treated individuals.

Conclusions:

All current classes of antiretroviral drugs only prevent infection of new cells but do not inhibit HIV RNA transcription in long-lived reservoir cells. Therefore, these differences in CA HIV RNA and DNA levels by treatment regimen suggest that NNRTIs are more potent in suppressing HIV residual replication than PIs, which may result in a smaller viral reservoir size.

Funding:

This work was supported by ZonMw (09120011910035) and FP7 Health (305522).

Heritability of the HIV-1 reservoir size and decay under long-term suppressive ART

The HIV-1 reservoir is the major hurdle to curing HIV-1. However, the impact of the viral genome on the HIV-1 reservoir, i.e. its heritability, remains unknown. We investigate the heritability of the HIV-1 reservoir size and its long-term decay by analyzing the distribution of those traits on viral phylogenies from both partial-pol and viral near full-length genome sequences. We use a unique nationwide cohort of 610 well-characterized HIV-1 subtype-B infected individuals on suppressive ART for a median of 5.4 years. We find that a moderate but significant fraction of the HIV-1 reservoir size 1.5 years after the initiation of ART is explained by genetic factors. At the same time, we find more tentative evidence for the heritability of the long-term HIV-1 reservoir decay. Our findings indicate that viral genetic factors contribute to the HIV-1 reservoir size and hence the infecting HIV-1 strain may affect individual patients’ hurdle towards a cure.

The HIV reservoir is a major hurdle for a cure of HIV, but the factors determining its size and dynamics remain unclear. Here the authors show in a large cohort of 610 HIV-1 infected individuals, who are on suppressive ART for a median of 5.4 years, that viral genetic factors contribute substantially to the HIV-1 reservoir size.

Novel dual HIV maintenance therapy with nevirapine plus lamivudine retain viral suppression through 144 weeks-A proof-of-concept study

OBJECTIVES

The aim of this proof-of-concept study is to test feasibility and efficacy of NVP plus Lamivudine (3TC) as novel simplified HIV maintenance dual therapy (DT) strategy.

METHODS

Patients under combined antiretroviral treatment (cART) with fully suppressed HIV plasma viral load (pVL) >24 months-whereof >6 months on an NVP- containing regimen-were switched to oral NVP plus 3TC for 24 weeks. Patients could then decide whether to continue DT or return to the previous cART. HIV pVL was monitored monthly until week 144. The primary outcome was confirmed viral failure (RNA >100 copies/ml). Low-level detection of HIV-RNA in plasma was compared in each patient with pre-study viral load measurements.

RESULTS

Twenty patients were included, switched to DT and all completed week 24. One patient decided thereafter to discontinue study participation for personal reasons. After a total of 144 observation weeks, none of the patients failed. The frequency of low- level HIV-RNA detection was not different from the period before randomization.

CONCLUSIONS

Our findings are surprising but given the nature of a proof-of-concept study, the results do not support the use of this dual regimen. However, as this dual HIV maintenance strategy was feasible and effective, over a period of 144 weeks, we suggest NVP plus 3TC warrants further evaluation as potential maintenance option in patients tolerating nevirapine. A properly sized multicentre non-inferiority trial is ongoing to further evaluate the value of this DT maintenance strategy.

Differences in HIV Markers between Infected Individuals Treated with Different ART Regimens: Implications for the Persistence of Viral Reservoirs

In adherent individuals, antiretroviral therapy (ART) suppresses HIV replication, restores immune function, and prevents the development of AIDS. However, ART is not curative and has to be followed lifelong. Persistence of viral reservoirs forms the major obstacle to an HIV cure. HIV latent reservoirs persist primarily by cell longevity and proliferation, but replenishment by residual virus replication despite ART has been proposed as another potential mechanism of HIV persistence. It is a matter of debate whether different ART regimens are equally potent in suppressing HIV replication. Here, we summarized the current knowledge on the role of ART regimens in HIV persistence, focusing on differences in residual plasma viremia and other virological markers of the HIV reservoir between infected individuals treated with combination ART composed of different antiretroviral drug classes.

Impact of Different Antiretroviral Strategies on Total HIV-DNA Level in Virologically Suppressed HIV-1 Infected Patients

Background:

Total HIV-DNA load in peripheral blood cell (PBMCs) reflects the global viral reservoir that seems not to be affected by antiretroviral treatment. However, some studies report-ed a different permeability of different drugs in cellular compartments.

Objective:

To investigate the relation between the amount of total HIV-1 DNA and different treatment strategies.

Methods:

Total HIV-1 DNA was quantified by real time PCR in PBMCs collected from 161 patients with long-term undetectable HIV-RNA receiving different therapy schedules (3-drug regimens or 2-drug regimen containing Raltegravir as integrase inhibitor).

Results:

Overall, HIV patients who started therapy with a median pre-ART CD4+ cell count >400 cells/mm3 and HIV viral load of 3 log10 copies/ml, achieved a lower amount of HIV total DNA. No significant correlation was found in DNA size when patients were stratified on the basis of different therapeutic protocols. However, HIV DNA load analysis, when only performed in HIV patients with a median pre-ART CD4+ cell count >200 cells/mm3 and HIV viral load < 3 log10 copies/ml, showed a significative DNA decrease in Raltegravir treated group with respect to the NNRTIs-treated group.

Conclusion:

The data emphasize that HIV-DNA level represents a predictive factor in long-term sup-pressive therapy patients. In addition, the diminished reservoir, only observed in patients treated with the NRTI-sparing regimen RAL plus PI/r before immunological and virological derangement, sug-gests that latest generation drugs, such as integrase inhibitors, might represent an optimal chance in the management of HIV infection.

INSTI-Based Triple Regimens in Treatment-Naïve HIV-Infected Patients Are Associated With HIV-RNA Viral Load Suppression at Ultralow Levels

Background

During antiretroviral therapy (ART), HIV-1-infected patients may present with ultralow (UL) HIV-RNA viral loads (VLs) below quantification levels of current assays. Reasons for UL-VL detection and its relation to virological rebound (VR) are unclear.

Methods

HIV-1-infected, ART-naïve patients followed at 2 university hospitals were included. All participants had an HIV-RNA >200 copies/mL at ART initiation and achieved a VL <50 copies/mL during ART. UL-VL was determined by the presence/absence of polymerase chain reaction signal detected using a commercially available assay (COBAS, TaqMan, Roche). Random-effects Poisson regression was used for assessing determinants of UL-VL not detected overtime and conditional risk set analysis for VR (1 VL > 200 copies/mL or 2 VL > 50 copies/mL) while accounting for frequency of VL measurements.

Results

Between 2009 and 2013, 717 patients initiated ART containing 2 nucleos(-t)ide reverse transcriptase inhibitors (NRTIs) plus a non-NRTI (29.4%), a protease inhibitor (58.4%), or an integrase-strand transfer inhibitor (INSTI; 12.1%). During a median (interquartile range) 3.4 (2.3–4.6) years, 676 (94.3%) patients achieved UL-VL not detected. In multivariable analysis, UL-VL not detected overtime was associated with younger age (P < .001), female gender (P = .04), lower baseline VL (P < .001), baseline CD4+ >500 vs <350/mm³ (P < .001), and INSTI-containing ART (P = .009). One hundred thirty-one (18.3%) patients had VR during follow-up, which was independently associated with a CD4/CD8 ratio <0.8 during follow-up (P = .01) and time spent with UL-VL not detected (P < .001). When UL-VL not detected occurred for ≥50% of the follow-up duration (n = 290), faster time to reach UL-VL not detected (P < .001), faster CD4+ T-cell count increase (P = .03), and faster CD4/CD8 ratio increase (P = .001) were observed.

Conclusions

VL suppression at an ultralow level is associated with INSTI-class ART initiation. Extensive VL suppression below ultralow detection could improve immune reconstitution.

The effects of antiretroviral therapy initiation time on HIV reservoir size in Chinese chronically HIV infected patients: a prospective, multi-site cohort study

Background

The effect of ART initiation time on HIV-1 DNA reservoir in chronically infected individuals is not well understood. Determining the potential influencing factors associated with a low HIV-1 DNA level in chronic infection is an important step toward drug-free control.

Methods

A prospective study included 444 chronically HIV-infected adults was performed. Participants were divided into two groups: early initiation group (EIG) or delayed initiation group (DIG) based on their baseline CD4 count; 350 to 500 and < 350 cells/mm³, respectively. Total HIV-1 DNA was measured by quantitative PCR. Using the Mann-Whitney U test, the HIV-1 DNA level at week 48 was compared between the two groups. The influencing factors of the HIV-1 DNA and factors associated with achieving a low HIV-1 level at week 48 were analyzed.

Results

The HIV-1 DNA at week 48 in EIG was significantly lower than in DIG [2.12 (1.80–2.51) vs 2.58 (2.21–2.87) log₁₀ copies/10⁶peripheral blood mononuclear cells (PBMCs); p = 0.001]. Early ART initiation was positively associated with lower HIV-1 DNA at week 48 (p = 0.025). Similarly, baseline HIV-1DNA (p = 0.001) was positively associated with HIV-1DNA at week 48 and baseline CD4/CD8 ratio (p = 0.001) was inversely associated with HIV-1DNA at week 48. Early ART initiation (p = 0.003) and baseline HIV-1 DNA level (p < 0.001) were positively associated with achieving HIV-1 DNA < 100 copies/10⁶ PBMCs at week 48.

Conclusion

Early ART initiation is positively associated with a smaller size of viral reservoir and a higher possibility of achieving a low HIV-1DNA level at week 48 in Chinese chronically HIV-1 infected adult.

Trial registration

NCT01844297; Registered 1 May, 2013.

Nanoformulated Antiretrovirals for Penetration of the Central Nervous System: State of the Art

The central nervous system is a very challenging HIV-1 sanctuary. But, despite complete suppression of plasmatic viral replication with current antiretroviral therapy, signs of HIV-1 replication can still be found in the cerebrospinal fluid in some patients. The main limitation to achieving HIV-1 eradication from the brain is related to the suboptimal concentrations of antiretrovirals within this site, due to their low permeation across the blood-brain barrier. In recent years, a number of reliable nanotechnological strategies have been developed with the aim of enhancing antiretroviral drug penetration across the blood-brain barrier. The aim of this review is to provide an overview of the different nanoformulated antiretrovirals, used in both clinical and preclinical studies, that are designed to improve their delivery into the brain by active or passive permeation mechanisms through the barrier. Different nanotechnological approaches have proven successful for optimizing antiretrovirals delivery to the central nervous system, with a likely benefit for HIV-associated neurocognitive disorders and a more debated contribution to the complete eradication of the HIV-1 infection.

HIV Replication at Low Copy Number and its Correlation with the HIV Reservoir: A Clinical Perspective

The efficacy of combination therapy (antiretroviral therapy - ARV) is demonstrated by the high rates of viral suppression achieved in most treated HIV patients. Whereas contemporary treatments may continuously suppress HIV replication, they do not eliminate the latent reservoir, which can reactivate HIV infection if ARV is discontinued. The persistence of HIV proviral DNA and infectious viruses in CD4+ T cells and others cells has long been considered a major obstacle in eradicating the HIV virus in treated patients. Moreover, recent studies have demonstrated the persistence of HIV replication at low copies in most patients on suppressive ARV. The source of this ‘residual viraemia’ and whether it declines over years of therapy remain unknown. Similarly, little is known regarding the biological relationships between the HIV reservoir and viral replication at low copies. The question of whether this ‘residual viraemia’ represents active replication or the release of non-productive virus from the reservoir has not been adequately resolved.

From a clinical perspective, both the quantification of the HIV reservoir and the detection of low levels of replication in full-responder patients on prolonged ARV may provide important information regarding the effectiveness of treatment and the eradication of HIV. To date, the monitoring of these two parameters has been conducted only for research purposes; the routine use of standardised tests procedure is lacking. This review aims to assess the current data regarding the correlation between HIV replication at low copies and the HIV reservoir and to provide useful information for clinicians.

HIV-1 Very Low Level Viremia Is Associated with Virological Failure in Highly Active Antiretroviral Treatment-Treated Patients

The aim of this study was to evaluate the impact of HIV-1 very low-level viremia (<50 copies/ml) on the 2-year risk of virological failure. A retrospective analysis including HIV-positive patients presenting two consecutive HIV RNA below 50 copies/ml (outpatient clinic in Italy, first semester of 2010) was performed. HIV RNA was measured through real time polymerase chain reaction (PCR) assay CAP/CTM HIV-1 version 2.0 (detection limit: 20 copies/ml) and stratified as undetectable RNA ("Target Not Detected", TND), <20 copies/ml, 20-50 copies/ml. After 96 weeks virological failure was defined as two consecutive viral loads above 50 copies/ml. Log-rank tests and a multivariate Cox proportional hazard model were used for univariate and multivariate analysis. A total of 1,055 patients (71.4% male, 87.4% white, aged 46.7 years) were included: nadir and current CD4 cell counts were 203 cells/mm(3) (106-292) and 554 cells/mm(3) (413-713.5). HIV RNA was undetectable in 781 patients (74%), <20 copies/ml in 190 patients (18%) and 20-50 copies/ml in 84 patients (8%). Virological failure was observed in 81 patients (7.7%); at multivariate analysis detectable RNA at baseline (p=0.017), HCV infection (p=0.020), more than three pills in the regimen (p=0.003), and duration of HIV RNA <50 copies/ml below 2 years (p<0.001) were independently associated with virological failure. In 14 patients newly selected resistance-associated mutations were observed. Undetectable HIV RNA by real-time PCR is significantly associated with a lower 2-year risk of virological failure along with Ab HCV negativity, longer viral control, and lower pill burden. Studies investigating the management of residual viremia under antiretroviral treatment are warranted.

HIV-1 RNA and HIV-1 DNA persistence during suppressive ART with PI-based or nevirapine-based regimens

OBJECTIVES

Whether ART regimens differ in their propensity to allow persistent HIV-1 detection remains unclear. To investigate this, we performed a cross-sectional study to characterize HIV-1 persistence in peripheral blood during suppressive therapy with NRTIs plus a PI or nevirapine.

METHODS

Residual plasma HIV-1 RNA was quantified by real-time PCR. Cell-associated proviral total HIV-1 DNA, unspliced and multiply spliced HIV-1 RNA and 2-long terminal repeat (2-LTR) circles were quantified by digital PCR.

RESULTS

Comparing PI with nevirapine recipients, residual plasma HIV-1 RNA detection rates were 47/80 (58.8%) versus 37/81 (45.7%), with median (IQR) levels of 4 (3-8) versus 4 (3-7) copies/mL (P = 0.207); detection was less likely with longer duration of suppressive ART (P = 0.020), independently of treatment. HIV-1 DNA was detected in all patients, with median levels of 2.3 (IQR 2.0-2.7) versus 2.5 (IQR 2.1-2.7) log10 copies/10(6) PBMCs, respectively; HIV-1 DNA levels were associated with pre-ART viral load (P = 0.004) and with residual HIV-1 RNA (P = 0.034), unspliced HIV-1 RNA (P = 0.001) and 2-LTR circles (P = 0.005), independently of treatment.

CONCLUSIONS

No significant differences were revealed in levels of residual plasma HIV-1 RNA, total HIV-1 DNA or intracellular markers of ongoing virus replication (unspliced and multiply spliced HIV-1 RNA and 2-LTR circles) between treatment groups.

Nanoformulation of antiretroviral drugs enhances their penetration across the blood brain barrier in mice

Eradication of virus by sanctuary sites is a main goal in HIV management. The central nervous system (CNS) is a classic model of sanctuary where viral replication occurs despite a complete viral suppression in peripheral blood. In recent years, nanotechnologies have provided a great promise in the eradication of HIV from the CNS. We hereby demonstrate for the first time that the structurally complex antiretroviral drug enfuvirtide (Enf), which normally is unable to penetrate the cerebrospinal fluid, is allowed to cross the blood brain barrier (BBB) in mice by conjugation with a nanoconstruct. Iron oxide nanoparticles coated with an amphiphilic polymer increase Enf translocation across the BBB in both in vitro and in vivo models. The mechanism involves the uptake of nanoconjugated-Enf in the endothelial cells, the nanocomplex dissociation and the release of the peptide, which is eventually excreted by the cells in the brain parenchyma.

FROM THE CLINICAL EDITOR

Despite the success of cocktail therapy of antiretroviral drugs, the complete eradication of HIV remains elusive, due to existence of viral sanctuary sites. The authors showed in this study that an antiretroviral drug complexed with iron oxide nanoparticles and coated with PMA amphiphilic polymer crosses the blood brain barrier. Furthermore, there was significant anti-viral activity. The results would aid further drug designs to eradicate HIV.

Strong and persistent correlation between baseline and follow-up HIV-DNA levels and residual viremia in a population of naïve patients with more than 4 years of effective antiretroviral therapy

In a longitudinal study on 181 naïve patients who responded to therapy (mean follow-up 4 years), high baseline human immunodeficiency virus (HIV)-RNA values correlated with high levels of cellular HIV-DNA at all time points (p < 0.0001, p 0.045, p 0.0055, and p 0.0025, respectively) and negatively correlated with undetectable residual viremia (URV; <2.5 copies/mL) at T1, T2, and T3 (p 0.026, p 0.0149, and p 0.0002, respectively). Baseline high HIV-DNA levels predicted the persistence of high values (p 0.0001) and negatively correlated with URV (p 0.0254, p 0.0481, and p 0.0085). These results suggest that baseline viral load, cellular HIV-DNA, and URV were strongly correlated over long-term follow-up of antiretroviral therapy responders.

Quantification of viral DNA during HIV-1 infection: A review of relevant clinical uses and laboratory methods

Effective antiretroviral therapy usually leads to undetectable HIV-1 RNA in the plasma. However, the virus persists in some cells of infected patients as various DNA forms, both integrated and unintegrated. This reservoir represents the greatest challenge to the complete cure of HIV-1 infection and its characteristics highly impact the course of the disease. The quantification of HIV-1 DNA in blood samples constitutes currently the most practical approach to measure this residual infection. Real-time quantitative PCR (qPCR) is the most common method used for HIV-DNA quantification and many strategies have been developed to measure the different forms of HIV-1 DNA. In the literature, several "in-house" PCR methods have been used and there is a need for standardization to have comparable results. In addition, qPCR is limited for the precise quantification of low levels by background noise. Among new assays in development, digital PCR was shown to allow an accurate quantification of HIV-1 DNA. Total HIV-1 DNA is most commonly measured in clinical routine. The absolute quantification of proviruses and unintegrated forms is more often used for research purposes.