Pharmacokinetic profile of raltegravir, elvitegravir and dolutegravir in plasma and mucosal secretions in rhesus macaques

In vitro antibacterial activity of antiretroviral drugs on key commensal bacteria from the human microbiota

Introduction

Antiretroviral therapy has improved life expectancy in HIV-infected patients. However, people living with HIV under antiretroviral therapy are at higher risks of developing chronic complications and acquiring multidrug resistant bacteria than healthy population. These factors have been associated with shifts in gut microbiome composition and immune activation. It is unclear how antiretroviral drugs affect gut microbiota composition, but it has been observed that antiretroviral treatment is not able to fully restore gut health after HIV infection. Additionally, some antiretroviral drugs have shown antibacterial activity suggesting that these drugs could have a direct impact on the human microbiome composition.

Methods

We determined the in vitro antibacterial activity of 16 antiretroviral drugs against a set of key clinically relevant and human commensal bacterial strains.

Results

Our results demonstrate that 5 antiretroviral drugs have in vitro antibacterial activity against gut and vaginal human commensal bacteria. Zidovudine has antibacterial activity against Escherichia coli, Klebsiella pneumoniae and Prevotella bivia, abacavir against Gardnerella vaginalis, efavirenz against G. vaginalis and P. bivia and bictegravir against Enterococcus spp. and G. vaginalis. Moreover, we describe for the first time that elvitegravir has antibacterial activity against G. vaginalis and P. bivia and, most importantly, against vancomycin-resistant Enterococcus spp. and methicillin-resistant Staphylococcus aureus strains with MIC values of 4-16 and 4 µg/mL, respectively showing high level of effectiveness against the tested multidrug-resistant bacteria.

Discussion

Our results underscore that some antiretroviral drugs may influence the human microbiota composition. In addition, we report the potential use of elvitegravir to treat multidrug-resistant Gram-positive bacteria warranting the need of clinical studies to repurpose this antiretroviral drug.

Pharmacokinetics, the Immunological Impact, and the Effect on HIV Ex-Vivo Infectivity of Maraviroc, Raltegravir, and Lopinavir in Men Who Have Sex with Men Using Postexposure Prophylaxis

Most of the studies using the colorectal tissue explants challenge model have been conducted after one single dose and before reaching a steady state. We consider that longer exposure as in 28-day postexposure prophylaxis (PEP) course and in an at-risk setting, such as after a sexual risk exposure to HIV could give us valuable information about these drugs. In a substudy we assessed pharmacokinetics, changes on immune system and ex-vivo rectal mucosal susceptibility to HIV-1 infection after taking maraviroc (MVC), raltegravir (RAL), and ritonavir-boosted lopinavir (LPV/r) PEP-based regimens in 30 men who have sex with men. Participants received 28 days of twice-daily MVC (n = 11), RAL (n = 10) or LPV/r (n = 9) all with tenofovir/emtricitabine (TDF/FTC) backbone. Blood, rectal fluid, and rectal tissue samples were collected at days 7, 28, and 90 after starting PEP. The samples obtained at day 90 were considered baseline. All studied antiretrovirals were quantifiable at 7 and 28 days in all tissues. Activation markers were increased in CD4 mucosal mononuclear cells (MMCs) after 28 days of MVC: CD38 + 68.5 versus 85.1, p = .008 and CD38+DR +16.1 versus 26.7, p = .008. Exposure to MVC at both endpoints (7 and 28 days) was associated with significant suppression of HIV-1BAL (p = .005 and p = .028), but we did not observe this effect with RAL or LPV/r. Merging together changes in MMC in all arms, we found a positive correlation in the CD8 T cell lineage between the infectivity at day 7 and activation (CD38+ r = 0.43, p = .025, DR + r = 0.547, p = .003 and 38+DR+ r = 0.526, p = .05), senescence (CD57+CD28- r = 0.479, p = .012), naive cells (RA+CCR7+ r = 0.484, p = .01), and CCR5 expression (r = 0.593, p = .001). We conclude that MVC in combination with TDF/FTC was associated with viral suppression in rectal explants and that overall ex-vivo HIV infectivity correlated with activation and senescence in CD8 MMCs.

Combination Antiretroviral Therapy and Immunophenotype of Feline Immunodeficiency Virus

Feline Immunodeficiency Virus (FIV) causes progressive immune dysfunction in cats similar to human immunodeficiency virus (HIV) in humans. Although combination antiretroviral therapy (cART) is effective against HIV, there is no definitive therapy to improve clinical outcomes in cats with FIV. This study therefore evaluated pharmacokinetics and clinical outcomes of cART (2.5 mg/kg Dolutegravir; 20 mg/kg Tenofovir; 40 mg/kg Emtricitabine) in FIV-infected domestic cats. Specific pathogen free cats were experimentally infected with FIV and administered either cART or placebo treatments (n = 6 each) for 18 weeks, while n = 6 naïve uninfected cats served as controls. Blood, saliva, and fine needle aspirates from mandibular lymph nodes were collected to quantify viral and proviral loads via digital droplet PCR and to assess lymphocyte immunophenotypes by flow cytometry. cART improved blood dyscrasias in FIV-infected cats, which normalized by week 16, while placebo cats remained neutropenic, although no significant difference in viremia was observed in the blood or saliva. cART-treated cats exhibited a Th2 immunophenotype with increasing proportions of CD4+CCR4+ cells compared to placebo cats, and cART restored Th17 cells compared to placebo-treated cats. Of the cART drugs, dolutegravir was the most stable and long-lasting. These findings provide a critical insight into novel cART formulations in FIV-infected cats and highlight their role as a potential animal model to evaluate the impact of cART on lentiviral infection and immune dysregulation.

Pharmacology of boosted and unboosted integrase strand transfer inhibitors for two-dose event-driven HIV prevention regimens among men

BACKGROUND

Event-driven HIV prevention strategies are a priority for users who do not require daily pre-exposure prophylaxis (PrEP). Regimens containing integrase strand transfer inhibitors (INSTIs) are under evaluation as alternatives to daily PrEP. To better understand INSTI distribution and inform dosing selection we compared the pharmacology of two-dose boosted elvitegravir and unboosted bictegravir regimens in MSM.

MATERIALS AND METHODS

Blood, rectal and penile secretions and rectal biopsies were collected from 63 HIV-negative MSM aged 18-49 years. Specimens were collected up to 96 h after two oral doses of tenofovir alafenamide and emtricitabine with elvitegravir boosted by cobicistat or unboosted bictegravir given 24 h apart. Antiretroviral drugs were measured by LC-MS.

RESULTS

Mean bictegravir plasma concentrations remained above the 95% protein-adjusted effective concentration 96 h after dosing [273 (95% CI: 164-456) ng/mL] whereas elvitegravir plasma concentrations became undetectable 48 h after the second dose. Bictegravir and elvitegravir reached rectal tissues within 2 h after the first dose, and elvitegravir tissue concentrations [1.07 (0.38-13.51) ng/mg] were greater than bictegravir concentrations [0.27 (0.15-0.70) ng/mg]. Both INSTIs became undetectable in tissues within 96 h. Elvitegravir and bictegravir were not consistently detected in penile secretions.

CONCLUSIONS

Whereas bictegravir plasma concentrations persist at least 4 days after a two-oral-dose HIV prophylaxis regimen, elvitegravir accumulates in mucosal tissues. Differing elvitegravir and bictegravir distribution may result in variable mucosal and systemic antiviral activity and can inform dosing strategies for event-driven HIV prevention.

A phase I study to assess safety, pharmacokinetics, and pharmacodynamics of a vaginal insert containing tenofovir alafenamide and elvitegravir

Background

New multi-purpose prevention technology (MPT) products are needed to prevent human immunodeficiency virus (HIV) and herpes simplex virus type 2 (HSV2). In this study, we evaluated a fast-dissolve insert that may be used vaginally or rectally for prevention of infection.

Objective

To describe the safety, acceptability, multi-compartment pharmacokinetics (PK), and in vitro modeled pharmacodynamics (PD) after a single vaginal dose of an insert containing tenofovir alafenamide (TAF) and elvitegravir (EVG) in healthy women.

Methods

This was a Phase I, open-label, study. Women (n=16) applied one TAF (20mg)/EVG (16mg) vaginal insert and were randomized (1:1) to sample collection time groups for up to 7 days post dosing. Safety was assessed by treatment-emergent adverse events (TEAEs). EVG, TAF and tenofovir (TFV) concentrations were measured in plasma, vaginal fluid and tissue, and TFV-diphosphate (TFV-DP) concentration in vaginal tissue. PD was modeled in vitro by quantifying the change in inhibitory activity of vaginal fluid and vaginal tissue against HIV and HSV2 from baseline to after treatment. Acceptability data was collected by a quantitative survey at baseline and post treatment.

Results

The TAF/EVG insert was safe, with all TEAEs graded as mild, and acceptable to participants. Systemic plasma exposure was low, consistent with topical delivery, while high mucosal levels were detected, with median TFV vaginal fluid concentrations exceeding 200,000 ng/mL and 1,000 ng/mL for up to 24 hours and 7 days post dosing, respectively. All participants had vaginal tissue EVG concentrations of > 1 ng/mg at 4 and 24 hours post dosing. The majority had tissue TFV-DP concentrations exceeding 1000 fmol/mg by 24 - 72 hours post dosing. Vaginal fluid inhibition of HIV-1 and HSV-2 in vitro significantly increased from baseline and was similarly high at 4 and 24 hours post dosing. Consistent with high tissue TFV-DP concentrations, p24 HIV antigen production from ectocervical tissues infected ex vivo with HIV-1 significantly decreased from baseline at 4 hours post dosing. HSV-2 production from tissue also decreased post treatment.

Conclusions

A single dose of TAF/EVG inserts met PK benchmarks, with PK data supporting an extended window of high mucosal protection. PD modeling supports mucosal protection against both HIV-1 and HSV-2. The inserts were safe and highly acceptable.

Clinical trial registration

ClinicalTrials.gov, identifier NCT03762772.

Endolysosome Localization of ERα Is Involved in the Protective Effect of 17α-Estradiol against HIV-1 gp120-Induced Neuronal Injury

Neurotoxic HIV-1 viral proteins contribute to the development of HIV-associated neurocognitive disorder (HAND), the prevalence of which remains high (30-50%) with no effective treatment available. Estrogen is a known neuroprotective agent; however, the diverse mechanisms of estrogen action on the different types of estrogen receptors is not completely understood. In this study, we determined the extent to which and mechanisms by which 17α-estradiol (17αE2), a natural less-feminizing estrogen, offers neuroprotection against HIV-1 gp120-induced neuronal injury. Endolysosomes are important for neuronal function, and endolysosomal dysfunction contributes to HAND and other neurodegenerative disorders. In hippocampal neurons, estrogen receptor α (ERα) is localized to endolysosomes and 17αE2 acidifies endolysosomes. ERα knockdown or overexpressing an ERα mutant that is deficient in endolysosome localization prevents 17αE2-induced endolysosome acidification. Furthermore, 17αE2-induced increases in dendritic spine density depend on endolysosome localization of ERα. Pretreatment with 17αE2 protected against HIV-1 gp120-induced endolysosome deacidification and reductions in dendritic spines; such protective effects depended on endolysosome localization of ERα. In male HIV-1 transgenic rats, we show that 17αE2 treatment prevents the development of enlarged endolysosomes and reduction in dendritic spines. Our findings demonstrate a novel endolysosome-dependent pathway that governs the ERα-mediated neuroprotective actions of 17αE2, findings that might lead to the development of novel therapeutic strategies against HAND.SIGNIFICANCE STATEMENT Extranuclear presence of membrane-bound estrogen receptors (ERs) underlie the enhancing effect of estrogen on cognition and synaptic function. The estrogen receptor subtype ERα is present on endolysosomes and plays a critical role in the enhancing effects of 17αE2 on endolysosomes and dendritic spines. These findings provide novel insight into the neuroprotective actions of estrogen. Furthermore, 17αE2 protected against HIV-1 gp120-induced endolysosome dysfunction and reductions in dendritic spines, and these protective effects of 17αE2 were mediated via endolysosome localization of ERα. Such findings provide a rationale for developing 17αE2 as a therapeutic strategy against HIV-associated neurocognitive disorders.

Pharmacokinetics of vaginally applied integrase inhibitors in macaques

OBJECTIVES

We conducted a detailed pharmacokinetic assessment in macaques treated with vaginal gels formulated with HIV integrase strand transfer inhibitors (INSTIs) to better understand drug distribution and identify INSTI concentrations associated with previously demonstrated in vivo protection against vaginal simian HIV challenge.

METHODS

Six macaques received vaginal gel containing 1% raltegravir (30 mg) once-weekly over 6 weeks. Following a washout period, five macaques received once-weekly gel containing 0.23% L-870,812 (7 mg). Drug concentrations were measured in plasma, mucosal fluids and vaginal tissues at baseline and 2, 5 and 24 h post-dosing.

RESULTS

The median maximum concentration (Cmax) for raltegravir and L-870,812 in plasma was below the limit of quantification and 41.1 ng/mL, respectively. The Cmax in vaginal fluids (1441 and 1250 μg/mL) and tissues (266.7 and 368.4 μg/g) was achieved 2-5 h after dosing, respectively. A similar half-life was observed for raltegravir and L-870,812 in vaginal fluids (8-10 h) and remained 3-4 orders of magnitude above the protein-adjusted IC95 (0.016 and 0.106 μg/mL, respectively) at 24 h. Drug concentrations in vaginal fluids correlated well with those in vaginal tissues (Pearson r ≥ 0.788). Both drugs were consistently detected in rectal fluids 2 h after vaginal dosing, albeit at much lower levels (31-92-fold) than those in vaginal fluids.

CONCLUSIONS

To the best of our knowledge, this study provides the first data on INSTI levels in vaginal tissues associated with in vivo protection and demonstrates rectal drug distribution of INSTIs after vaginal dosing. These findings may inform dose selection for topical products with INSTIs for HIV prevention.

Pharmacokinetic/pharmacodynamic investigation of raltegravir with or without lamivudine in the context of HIV-1 pre-exposure prophylaxis (PrEP)

Background

To characterize their potential use in pre-exposure prophylaxis (PrEP) we compared the pharmacokinetics of raltegravir and lamivudine in genital tissue against ex vivo tissue infection with HIV-1.

Methods

Open-label trial of 36 HIV-negative females and males randomized to 7 days raltegravir 400 mg twice daily and 7 days raltegravir 400 mg+lamivudine 150 mg twice daily (after washout), or vice versa. Blood, saliva, rectal fluid, rectal tissue, vaginal fluid and vaginal tissue were sampled at baseline and on and off PrEP during a total of 12 days, for pharmacokinetics and antiviral activity via ex vivo HIV-1_BaL challenge. Ex vivo infectivity was compared with baseline. The trial has been registered in https://clinicaltrials.gov/ with the identifier NCT03205566.

Results

Steady state for both drugs was reached by day 4. Dosing with raltegravir alone provided modest ex vivo HIV protection with higher drug levels in rectal tissue and vaginal tissue than in plasma on and off PrEP. Off PrEP, plasma and vaginal concentrations declined rapidly, while persisting in the rectum. On PrEP, the highest lamivudine concentrations were in the rectum, followed by vaginal tissue then plasma. Lamivudine washout was rapid in plasma, while persisting in the rectum and vagina. Raltegravir/lamivudine increased ex vivo protection on and off PrEP compared with raltegravir alone, reaching maximum protection at day 2 in rectal tissue and at day 8 in vaginal tissue.

Conclusions

Raltegravir 400 mg+lamivudine 150 mg showed high levels of ex vivo HIV protection, associated with high drug concentrations persisting after discontinuation in vaginal and rectal compartments, supporting further investigation of these agents for PrEP.

Antiretroviral drug exposure in urethral and glans surface sampling of the penis

BACKGROUND

HIV exposure to penile tissues provides a risk of acquisition among men, yet studies evaluating penile antiretroviral (ARV) drug distribution have been lacking. We measured ARVs on urethral and glans surface swabs collected following a dose of tenofovir alafenamide, emtricitabine, elvitegravir, darunavir and cobicistat.

METHODS

Thirty-five HIV-negative male participants provided urethral swabs, glans swabs, rectal swabs, blood and urine up to 96 h following a single dose of tenofovir alafenamide/emtricitabine/elvitegravir/cobicistat and darunavir. ARVs were measured by liquid chromatography-mass spectrometry with a lower limit of detection (LOD) of 1 ng/swab for swabs and 10 ng/mL for plasma and urine. Concentrations are reported as median and range.

RESULTS

Urethral swab emtricitabine and darunavir concentrations peaked at 4 h for emtricitabine (36 ng/swab; 3-307 ng/swab) and 8 h for darunavir (25 ng/swab; 2-52 ng/swab). Glans swab emtricitabine and darunavir concentrations peaked 24 h after dosing (emtricitabine 14 ng/swab, <LOD-328 ng/swab; darunavir 6 ng/swab, <LOD-149 ng/swab). Estimated peak urethral secretion emtricitabine and darunavir concentrations are between 10 and 20 μg/mL, similar to rectal secretions, 4-fold greater than in plasma, but 2-fold lower than in urine. Tenofovir and elvitegravir were detected on less than 20% of urethral or glans swabs collected within 24 h of dosing.

CONCLUSIONS

We document ARV dosing in the urethra and on the glans surface with high drug concentrations noted for emtricitabine and darunavir and lower tenofovir and elvitegravir concentrations. Data suggest a potential protective role of urethral emtricitabine or darunavir against penile HIV acquisition.

Single oral dose for HIV pre or post-exposure prophylaxis: user desirability and biological efficacy in macaques

BACKGROUND

Daily oral pre- or post-exposure prophylaxis (PrEP or PEP) is highly effective in preventing HIV infection. However, many people find it challenging to adhere to a daily oral regimen. Chemoprophylaxis with single oral doses of antiretroviral drugs taken before or after sex may better adapt to changing or unanticipated sexual practices and be a desirable alternative to daily PrEP or PEP. We investigated willingness to use a single oral pill before or after sex among men who have sex with men (MSM) and assessed the biological efficacy of a potent antiretroviral combination containing elvitegravir (EVG), emtricitabine (FTC), and tenofovir alafenamide (TAF).

METHODS

Data on willingness to use single-dose PrEP or PEP were obtained from the 2017 cycle of the American Men's Internet Survey (AMIS), an annual online behavioral surveillance survey of MSM in the United States. Antiretroviral drug levels were measured in humans and macaques to define drug distribution in rectal tissue and identify clinically relevant doses for macaque modeling studies. The biological efficacy of a single dose of FTC/TAF/EVG as PrEP or PEP was investigated using a repeat-challenge macaque model of rectal HIV infection.

FINDINGS

Through pharmacokinetic assessment in humans and macaques we found that EVG penetrates and concentrates in rectal tissues supporting its addition to FTC/TAF to boost and extend chemoprophylactic activity. Efficacy estimates for a single oral dose given to macaques 4h before or 2h after SHIV exposure was 91•7%[35•7%-98•9%] and 100%, respectively, compared to 80•1%[13•9%-95•4%] and 64•6%[-19•4%-89•5%] when single doses were given 6 and 24h post challenge, respectively. A two-dose regimen at 24h and 48h after exposure was also protective [77•1%[1•7%-94•7%].

INTERPRETATION

Informed by user willingness, human and macaque pharmacokinetic data, and preclinical efficacy we show that single-dose prophylaxis before or after sex is a promising HIV prevention strategy. Carefully designed clinical trials are needed to determine if any of these strategies will be effective in humans.

FUNDING

Funded by CDC intramural funds, CDC contract HCVJCG2-2016-03948 (to CFK), and a grant from the MAC AIDS Fund and by the National Institutes of Health [P30AI050409] - the Emory Center for AIDS Research (to MZ and TS).

Novel Transmitted/Founder Simian-Human Immunodeficiency Viruses for Human Immunodeficiency Virus Latency and Cure Research

A robust simian-human immunodeficiency virus (SHIV)-macaque model of latency is critical to investigate eradicative and suppressive strategies that target HIV-1 Env. To this end, we previously reported a novel strategy for constructing SHIVs that bear primary or transmitted/founder (TF) Envs with modifications at Env residue 375 that enable efficient replication in Indian rhesus macaques (RM). Such TF SHIVs, however, have not been examined for their suitability for HIV-1 latency and cure research. Here, we evaluate two promising TF SHIVs, SHIV.D.191859 and SHIV.C.CH848, which encode TF subtype D and C HIV-1 Envs, respectively, for their viral kinetics and persistence during suppressive combination antiretroviral therapy (cART) and treatment interruption in RM. Our results suggest that the viral kinetics of these SHIVs in RM during acute, early, and chronic infection, and upon cART initiation, maintenance and discontinuation, mirror those of HIV-1 infection. We demonstrate consistent early peak and set point viremia, rapid declines in viremia to undetectable plasma titers following cART initiation, infection of long-lived cellular subsets and establishment of viral latency, and viral rebound with return to pretreatment set point viremia following treatment interruption. The viral dynamics and reservoir biology of SHIV.D.191859, and to a lesser extent SHIV.C.CH848, during chronic infection, cART administration, and upon treatment interruption suggest that these TF SHIVs are promising reagents for a SHIV model of HIV-1 latency and cure.IMPORTANCE Simian-human immunodeficiency viruses (SHIVs) have been successfully used for over 2 decades to study virus-host interactions, transmission, and pathogenesis in rhesus macaques. The majority of Env trimers of most previously studied SHIVs, however, do not recapitulate key properties of transmitted/founder (TF) or primary HIV-1 isolates, such as CCR5 tropism, tier 2 neutralization resistance, and native trimer conformation. Here, we test two recently generated TF SHIVs, SHIV.D.191859 and SHIV.C.CH848, which were designed to address these issues as components of a nonhuman primate model of HIV-1 latency. We conclude that the TF SHIV-macaque model reflects several hallmarks of HIV and SIV infection and latency. Results suggest that this model has broad applications for evaluating eradicative and suppressive strategies against the HIV reservoir, including Env-specific interventions, therapeutic vaccines, and engineered T cells.

Antiretroviral Penetration across Three Preclinical Animal Models and Humans in Eight Putative HIV Viral Reservoirs

For HIV cure strategies like "kick and kill" to succeed, antiretroviral (ARV) drugs must reach effective concentrations in putative viral reservoirs. We characterize penetration of six ARVs in three preclinical animal models and humans. We found that standard dosing strategies in preclinical species closely mimicked tissue concentrations in humans for some, but not all, ARVs. These results have implications for interpreting HIV treatment, prevention, or cure interventions between preclinical and clinical models.

Spatial distribution of elvitegravir and tenofovir in rat brain tissue: Application of matrix-assisted laser desorption/ionization mass spectrometry imaging and liquid chromatography/tandem mass spectrometry

RATIONALE

The complexity of central nervous system (CNS) drug delivery is the main obstacle with the blood-brain barrier (BBB) known to restrict access of most pharmaceutical drugs into the brain. Mass spectrometry imaging (MSI) offers possibilities for studying drug deposition into the CNS.

METHODS

The deposition and spatial distribution of the two antiretroviral drugs elvitegravir and tenofovir in the brain were investigated in healthy female Sprague-Dawley rats following a single intraperitoneal administration (50 mg/kg). This was achieved by the utilization of quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) and matrix-assisted laser desorption/ionization (MALDI) MSI.

RESULTS

LC/MS/MS showed that elvitegravir has better BBB penetration, reaching maximum concentration in the brain (C_max brain) of 976.5 ng/g. In contrast, tenofovir displayed relatively lower BBB penetration, reaching C_max brain of 54.5 ng/g. MALDI-MSI showed the heterogeneous distribution of both drugs in various brain regions including the cerebral cortex.

CONCLUSIONS

LC/MS/MS and MALDI-MSI provided valuable information about the relative concentration and the spatial distribution of the two common antiretroviral drugs. This study has also shown the capability of MALDI-MSI for direct visualization of pharmaceutical drugs in situ.

Genital reservoir: a barrier to functional cure?

PURPOSE OF REVIEW

HIV functional cure requires the elimination or a major reduction of HIV reservoir pool including male and female genital HIV reservoirs. A comprehensive understanding of HIV dynamics in these compartments is mandatory.

RECENT FINDINGS

Data from chronically HIV-infected therapy-naïve individuals or fully suppressed on combined antiretroviral therapy (cART) or undergoing ART interruptions are now available. Using paired blood/genital samples, HIV-RNA/DNA quantification and sequencing provide new insights on HIV dynamics in genital reservoirs.

SUMMARY

In the absence of cART, HIV shedding in semen and cervicovaginal secretions is frequent, resulting most likely from passive transfer of HIV strains that originates from bloodborne virions or infected blood cells. Partial and intermittent HIV compartmentalization in the male and female genital tracts can occur not only in chronically infected ART-naïve individuals but also when cART is used to prevent active blood replication. This transient autonomous HIV replication in the genital reservoir in a few individuals originates from recent transfer of virions or infected blood cells. cART interruption studies showed that blood and genital quasispecies are closely related, in agreement with a passive transfer. Altogether these data suggest that HIV genital reservoirs seem not to be a significant barrier to achieve HIV cure.

Repeated rectal application of a hyperosmolar lubricant is associated with microbiota shifts but does not affect PrEP drug concentrations: results from a randomized trial in men who have sex with men

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is highly effective in preventing HIV infection among men who have sex with men (MSM). The effects of consistent personal lubricant use in the rectum on tissue PrEP drug concentrations and the rectal microbiota are unknown. We investigated rectal PrEP drug concentrations and the microbiota in MSM before and after repeated rectal application of a hyperosmolar lubricant.

METHODS

We randomized 60 HIV-negative MSM to apply 4 mL of hyperosmolar rectal lubricant daily (n = 20), take daily oral TDF/FTC (n = 19), or both (n = 21) for seven days. Blood, rectal biopsies and rectal secretions were collected via rigid sigmoidoscopy before and on day 8 after product use. Tenofovir (TFV) and FTC as well as their intracellular metabolites tenofovir-diphosphate (TFV-DP), FTC-triphosphate (FTC-TP) were measured by HPLC-mass spectrometry. Rectal mucosal microbiota was sequenced with 16S rRNA sequencing using Illumina MiSeq.

RESULTS

Seven days of lubricant application was not associated with differences in PrEP drug concentrations in rectal tissue or secretions. Lubricant use was associated with a decrease in the relative abundance of the Bacteroides genus (p = 0.01) and a non-significant increase in the Prevotella genus (p = 0.09) in the rectum. PrEP drug concentrations in rectal tissue and secretions were not associated with microbiota composition or diversity either before or after lubricant use.

CONCLUSIONS

Repeated rectal application of a hyperosmolar lubricant does not affect mucosal PrEP drug concentrations but is associated with changes in the rectal microbiome.

Tenofovir disoproxil fumarate/emtricitabine plus ritonavir-boosted lopinavir or cobicistat-boosted elvitegravir as a single-tablet regimen for HIV post-exposure prophylaxis

Objectives

To assess HIV-1 post-exposure prophylaxis (PEP) non-completion at day 28, comparing ritonavir-boosted lopinavir versus cobicistat-boosted elvitegravir as a single-tablet regimen (STR), using tenofovir disoproxil fumarate/emtricitabine with both of these therapies.

Methods

A prospective, open, randomized clinical trial was performed. Individuals attending the emergency room due to potential sexual exposure to HIV and who met criteria for PEP were randomized 1:3 into two groups receiving either 400/100 mg of lopinavir/ritonavir (n = 38) or 150/150 mg of elvitegravir/cobicistat (n = 119), with both groups also receiving 245/200 mg of tenofovir disoproxil fumarate/emtricitabine. Five follow-up visits were scheduled at days 1, 10, 28, 90 and 180. The primary endpoint was PEP non-completion at day 28. Secondary endpoints were adherence, adverse effects and rate of seroconversions. Clinical trials.gov number: NCT08431173.

Results

Median age was 32 years and 95% were males. PEP non-completion at day 28 was 36% (n = 57), with a trend to be higher in the lopinavir/ritonavir arm [lopinavir/ritonavir 47% (n = 18) versus elvitegravir/cobicistat 33% (n = 39), P = 0.10]. We performed a modified ITT analysis including only those patients who attended on day 1. PEP non-completion in this subgroup was higher in the lopinavir/ritonavir arm than in the elvitegravir/cobicistat arm (33% versus 15%, respectively, P = 0.04). Poor adherence was significantly higher in the lopinavir/ritonavir arm versus the elvitegravir/cobicistat arm (47% versus 9%, respectively, P < 0.0001). Adverse events were reported by 73 patients (59%), and were significantly more common in the lopinavir/ritonavir arm (90% versus 49%, P = 0.0001). A seroconversion was observed in the elvitegravir/cobicistat arm in a patient with multiple exposures before and after PEP.

Conclusions

A higher PEP non-completion, poor adherence and adverse events were observed in patients allocated to the lopinavir/ritonavir arm, suggesting that STR elvitegravir/cobicistat is a well-tolerated antiretroviral for PEP.

Raltegravir blocks the infectivity of red-fluorescent-protein (mCherry)-labeled HIV-1JR-FL in the setting of post-exposure prophylaxis in NOD/SCID/Jak3-/- mice transplanted with human PBMCs

Employing NOD/SCID/Jak3-/- mice transplanted with human PBMCs (hNOJ mice) and replication-competent, red-fluorescent-protein (mCherry; mC)-labeled HIV-1JR-FL (HIVmC), we examined whether early antiretroviral treatment blocked the establishment of HIV-1 infection. The use of hNOJ mice and HIVmC enabled us to visually locate infection foci and to examine the early dynamics of HIVmC infection without using a large amount of antiretroviral unlike in non-human primate models. Although when raltegravir (RAL) administration was begun 1 day after intraperitoneal (ip) inoculation of HIVmC, no plasma p24 or plasma HIV-1-RNA (pRNA) were detected in 10 of 12 hNOJ (hNOJmCRAL+) mice as assessed on the last day of the 14-day continuous twice-daily RAL administration, all 10 untreated hNOJmC (hNOJmCRAL-) mice became positive for p24 and pRNA and had significantly swollen lymph nodes in peritoneal cavity and abundant p24+/mC+/CD3+/CD4+ T cells and p24+/mC+/CD68+ monocytes/macrophages were identified in their omenta and mesenteric lymphoid tissues/lymph nodes upon necropsy of the mice on day 14. In 12 hNOJmCRAL+ mice, no significantly swollen lymph nodes were seen compared to hNOJmCRAL- mice; however, in the omentum of the 2 hNOJmCRAL+ mice that were positive for pRNA and in site RNA, mC+/p24+/CD3+/CD83+ cells were identified, suggesting that viral breakthrough occurred later in the observation period. The present data suggest that the use of hNOJ mouse model and HIVmC may shed light on the study of early-phase dynamics of HIV-1 infection and cellular events in post-exposure/pre-exposure prophylaxis.

Pharmacokinetic and Tissue Distribution Profile of Long Acting Tenofovir Alafenamide and Elvitegravir Loaded Nanoparticles in Humanized Mice Model

PURPOSE

Non-adherence to the antiretroviral (ARV) regimen is a critical factor in determining efficacy of ARV drugs for pre-exposure prophylaxis (PrEP). A long-acting parenteral formulation may be an effective alternative to daily oral dosing. A pharmacokinetic and tissue distribution study of drug-loaded nanoparticle (NP) was performed in female humanized CD34⁺-NSG mice.

METHODS

Mice received 200 mg/kg each of tenofovir alafenamide (TAF) and elvitegravir (EVG) as free drugs (TAF + EVG solution) or as drug loaded NP (TAF + EVG NP) formulation by subcutaneous (SubQ) administration. Plasma and tissue were collected to determine tenofovir (TFV) and EVG concentrations using LC-MS/MS. Non-compartmental analysis was performed using WinNonlin.

RESULTS

SubQ administration of TAF + EVG NP formulation resulted in long residence time and exposure for both drugs. The AUC_(0-72h) of TFV and EVG was 14.1 ± 2.0, 7.2 ± 1.8 μg × hr./mL from drugs in solution (free) and the AUC_(0-14day) for the same drugs was 23.1 ± 4.4, 39.7 ± 6.7 μg × hr./mL from NPs. The observed elimination half-life (t_1/2) for TFV of free and NPs were 14.2 h, 5.1 days and for EVG 10.8 h, 3.3 days, respectively.

CONCLUSION

This study documents that a TAF + EVG NP provides sustained release, which can overcome patient non-adherence to dosing and may facilitate prediction of appropriate protective drug concentration for HIV prophylaxis.

Multimodal analysis of drug transporter expression in gastrointestinal tissue

OBJECTIVES

Drug transporters affect antiretroviral therapy (ART) tissue disposition, but quantitative measures of drug transporter protein expression across preclinical species are not available. Our objective was to use proteomics to obtain absolute transporter concentrations and assess agreement with corresponding gene and immunometric protein data.

DESIGN

In order to make interspecies comparisons, two humanized mouse [hu-HSC-Rag (n = 41); bone marrow-liver-thymus (n = 13)] and one primate [rhesus macaque (nonhuman primate, n = 12)] models were dosed to steady state with combination ART. Ileum and rectum were collected at necropsy and snap frozen for analysis.

METHODS

Tissues were analyzed for gene (quantitative PCR) and protein [liquid chromatography-mass spectrometry (LC-MS) proteomics and western blot] expression and localization (immunohistochemistry) of ART efflux and uptake transporters. Drug concentrations were measured by LC-MS/MS. Multivariable regression was used to determine the ability of transporter data to predict tissue ART penetration.

RESULTS

Analytical methods did not agree, with different trends observed for gene and protein expression. For example, quantitative PCR analysis showed a two-fold increase in permeability glycoprotein expression in nonhuman primates versus mice; however, proteomics showed a 200-fold difference in the opposite direction. Proteomics results were supported by immunohistochemistry staining showing extensive efflux transporter localization on the luminal surface of these tissues. ART tissue concentration was variable between species, and multivariable regression showed poor predictive power of transporter data.

CONCLUSION

Lack of agreement between analytical techniques suggests that resources should be focused on generating downstream measures of protein expression to predict drug exposure. Taken together, these data inform the use of preclinical models for studying ART distribution and the design of targeted therapies for HIV eradication.

Alterations in cellular pharmacokinetics and pharmacodynamics of elvitegravir in response to ethanol exposure in HIV-1 infected monocytic (U1) cells

Ethanol consumption is negatively associated with antiretroviral therapy (ART) adherence and general health in HIV positive individuals. Previously, we demonstrated ethanol-mediated alterations to metabolism of elvitegravir (EVG) in human liver microsomes. In the current study, we investigated ethanol influence on the pharmacokinetic and pharmacodynamic interactions of EVG in HIV infected monocytic (U1) cells. U1 cells were treated with 5 μM EVG, 2 μM Cobicistat (COBI), a booster drug, and 20 mM ethanol for up to 24 hours. EVG, HIV p24 levels, alterations in cytochrome P450 (CYP) 3A4, MRP1, and MDR1 protein expressions were measured. Presence of ethanol demonstrated a significant effect on the total exposures of both EVG and EVG in combination with COBI. Ethanol also increased the HIV replication despite the presence of drugs and this elevated HIV replication was reduced in the presence of MRP1 and MDR1 inhibitors. Consequently, a slight increase in EVG concentration was observed in the presence of MRP1 inhibitor but not with MDR1 inhibitor. Furthermore, CYP3A4, MRP1 and MDR1 protein levels were significantly induced in treatment groups which included ethanol compared to those with no treatment. In summary, these findings suggest that Ethanol reduces intra cellular EVG exposure by modifying drug metabolism and transporter protein expression. This study provides valuable evidence for further investigation of ethanol effects on the intracellular concentration of EVG in ex vivo or in vivo studies.

Tenofovir alafenamide and elvitegravir loaded nanoparticles for long-acting prevention of HIV-1 vaginal transmission

OBJECTIVE

This report presents tenofovir (TFV) alafenamide (TAF) and elvitegravir (EVG) fabricated into nanoparticles for subcutaneous delivery as prevention strategy.

DESIGN

Prospective prevention study in humanized bone marrow-liver-thymus (hu-BLT) mice.

METHODS

Using an oil-in-water emulsion solvent evaporation technique, TAF + EVG drugs were entrapped together into nanoparticles containing poly(lactic-co-glycolic acid). In-vitro prophylaxis studies (90% inhibition concentration) compared nanoparticles with drugs in solution. Hu-BLT (n = 5/group) mice were given 200 mg/kg subcutaneous, and vaginally challenged with HIV-1 [5 × 10 tissue culture infectious dose for 50% of cells cultures (TCID50)] 4 and 14 days post-nanoparticle administration (post-nanoparticle injection). Control mice (n = 5) were challenged at 4 days. Weekly plasma viral load was performed using RT-PCR. Hu-BLT mice were sacrificed and lymph nodes were harvested for HIV-1 viral RNA detection by in-situ hybridization. In parallel, CD34 humanized mice (3/time point) compared TFV and EVG drug levels in vaginal tissues from nanoparticles and solution. TFV and EVG were analyzed from tissue using liquid chromatograph-tandem mass spectrometry (LC-MS/MS).

RESULTS

TAF + EVG nanoparticles were less than 200 nm in size. In-vitro prophylaxis indicates TAF + EVG nanoparticles 90% inhibition concentration was 0.002 μg/ml and TAF + EVG solution was 0.78 μg/ml. TAF + EVG nanoparticles demonstrated detectable drugs for 14 days and 72 h for solution, respectively. All hu-BLT control mice became infected within 14 days after HIV-1 challenge. In contrast, hu-BLT mice that received nanoparticles and challenged at 4 days post-nanoparticle injection, 100% were uninfected, and 60% challenged at 14 days post-nanoparticle injection were uninfected (P = 0.007; Mantel-Cox test). In-situ hybridization confirmed these results.

CONCLUSION

This proof-of-concept study demonstrated sustained protection for TAF + EVG nanoparticles in a hu-BLT mouse model of HIV vaginal transmission.

Elvitegravir for the treatment of HIV

INTRODUCTION

Current antiretrovirals (ARVs) have demonstrated the ability to prolong the life of an HIV infected individual via suppression of the virus and subsequent restoration of immune function. Despite significant advancement, there remains an opportunity for improvement. One ARV that attempts to fill global HIV therapeutic needs by balancing convenience, safety, and efficacy is elvitegravir (EVG). Areas covered: Using MEDLINE/PubMed, a literature search was conducted for published articles on the safety and efficacy of EVG in the treatment of HIV infection. Expert opinion: EVG offers clinicians a convenient choice for HIV-positive patients that is safe and effective for both treatment-naïve and experienced patients, as well as an option for regimen simplification in virologically suppressed patients. EVG is conveniently co-formulated in fixed dose combination tablets to be taken once daily with food. EVG does not require dose adjustment for patients with severe renal impairment or mild to moderate liver disease. Importantly, EVG requires co-administration with a pharmacokinetic enhancer (i.e., ritonavir or cobicistat) in order to achieve therapeutic levels and facilitate once daily dosing. As a consequence, clinicians must carefully review concomitant medications and navigate potential drug-drug interactions mediated through potent inhibition of cytochrome P450 3A enzymes by ritonavir and cobicistat.

A long-acting formulation of the integrase inhibitor raltegravir protects humanized BLT mice from repeated high-dose vaginal HIV challenges

OBJECTIVES

Pre-exposure prophylaxis (PrEP) using antiretroviral drugs (ARVs) has been shown to reduce HIV transmission in people at high risk of HIV infection. Adherence to PrEP strongly correlates with the level of HIV protection. Long-acting injectable ARVs provide sustained systemic drug exposures over many weeks and can improve adherence due to infrequent parenteral administration. Here, we evaluated a new long-acting formulation of raltegravir for prevention of vaginal HIV transmission.

METHODS

Long-acting raltegravir was administered subcutaneously to BALB/c, NSG (NOD-scid-gamma) and humanized BLT (bone marrow-liver-thymus) mice and rhesus macaques. Raltegravir concentration in peripheral blood and tissue was analysed. Suppression of HIV replication was assessed in infected BLT mice. Two high-dose HIV vaginal challenges were used to evaluate protection from HIV transmission in BLT mice.

RESULTS

Two weeks after a single subcutaneous injection of long-acting raltegravir in BLT mice (7.5 mg) and rhesus macaques (160 mg), the plasma concentration of raltegravir was comparable to 400 mg orally, twice daily in humans. Serum collected from mice 3 weeks post-administration of long-acting raltegravir efficiently blocked HIV infection of TZM-bl indicator cells in vitro. Administration of long-acting raltegravir suppressed viral RNA in plasma and cervico-vaginal fluids of infected BLT mice, demonstrating penetration of active raltegravir into the female reproductive tract. Using transmitted/founder HIV we observed that BLT mice administered a single subcutaneous dose of long-acting raltegravir were protected from two high-dose HIV vaginal challenges 1 week and 4 weeks after drug administration.

CONCLUSIONS

These preclinical results demonstrated the efficacy of long-acting raltegravir in preventing vaginal HIV transmission.

Nonhuman Primates and Humanized Mice for Studies of HIV-1 Integrase Inhibitors: A Review

Since the discovery of the first inhibitors of HIV replication, drug resistance has been a major problem in HIV therapy due in part to the high mutation rate of HIV. Therefore, the development of a predictive animal model is important to identify impending resistance mutations and to possibly inform treatment decisions. Significant advances have been made possible through use of nonhuman primates infected by SIV, SHIV, and simian-tropic HIV-1 (stHIV-1), and use of humanized mouse models of HIV-1 infections. In this review, we describe some of the findings from animal models used for the preclinical testing of integrase strand transfer inhibitors. These models have led to important findings about the potential role of integrase strand transfer inhibitors in both the prevention and treatment of HIV-1 infection.

Assessment of penile erection methods in rhesus macaques to model pharmacokinetics of antiretroviral drugs and penile infection with simian immunodeficiency virus

BACKGROUND

An established macaque model to assess HIV interventions against penile transmission is currently not available. Physiological changes during penile erections may affect susceptibility to infection and drug pharmacokinetics (PK). Here, we identify methods to establish erections in macaques to evaluate penile transmission, PK, and efficacy under physiologic conditions.

METHODS

Penile rigidity and length were evaluated in eight rhesus macaques following rectal electrostimulation (RES), vibratory stimulation (VS), or pharmacological treatment with Sildenafil Citrate (Viagra) or Alprostadil.

RESULTS

Rectal electrostimulation treatment increased penile rigidity (>82%) and length (2.5 ± 0.58 cm), albeit the response was transient. In contrast, VS alone or coupled with Viagra or Alprostadil failed to elicit an erection response.

CONCLUSION

Rectal electrostimulation treatment elicits transient but consistent penile erections in macaques. High rigidity following RES treatment demonstrates increased blood flow and may provide a functional model for penile PK evaluations and possibly simian immunodeficiency virus (SIV) transmission under erect conditions.

Mucosal tissue pharmacokinetics of the integrase inhibitor raltegravir in a humanized mouse model: Implications for HIV pre-exposure prophylaxis

Orally administered anti-retroviral drugs show considerable promise for HIV/AIDS pre-exposure prophylaxis (PrEP). For the success of these strategies, pharmacokinetic (PK) data defining the optimal concentration of the drug needed for protection in relevant mucosal exposure sites is essential. Here we employed a humanized mouse model to derive comprehensive PK data on the HIV integrase inhibitor raltegravir (RAL), a leading PrEP drug candidate. Under steady state conditions following oral dosing, plasma and multiple mucosal tissues were sampled simultaneously. RAL exhibited higher drug exposure in mucosal tissues relative to that in plasma with one log higher exposure in vaginal and rectal tissue and two logs higher exposure in intestinal mucosa reflecting the trends seen in the human studies. These data demonstrate the suitability of RAL for HIV PrEP and validate the utility of humanized mouse models for deriving important preclinical PK-PD data.