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Tenofovir diphosphate (TFVdp; an active metabolite of oral HIV pre-exposure prophylaxis [PrEP]) is measured in dried blood spots (DBS) to estimate adherence. However, TFVdp's long half-life in whole blood may lead to misclassification following a recent change in adherence. PrEP's other metabolite, emtricitabine triphosphate (FTCtp), has a shorter half-life in whole blood but adherence thresholds are undefined. We characterized DBS TFVdp and FTCtp concentrations across many dosing scenarios. Population PK models were fit to TFVdp and FTCtp DBS concentrations from a directly observed therapy study (NCT03218592). Concentrations were simulated for 90 days of daily dosing followed by 90 days of 1 to 7 doses/week and for event-driven PrEP (edPrEP) scenarios. Thresholds of 1000 and 200 fmol/punch, for TFVdp and FTCtp, respectively, were reflective of taking 4 doses/week (a minimum target for effective PrEP in men). TFVdp was1000 fmol/punch for 17 days after initiating daily PrEP and1000 fmol/punch for 62 days after decreasing to 3 doses/week. Respectively, FTCtp was200 fmol/punch for 4 days and200 fmol/punch for 6 days. Accuracy of edPrEP adherence classification depended on duration between last sex act and DBS sampling for both measures with misclassification ranging from 9-100%. These data demonstrate adherence misclassification by DBS TFVdp for 2 months following a decline in adherence, elucidating the need for FTCtp to estimate recent adherence. We provide proof of principle that individualized interpretation is needed to support edPrEP adherence monitoring. Our collective approach facilitates clinicians' ability to interpret DBS results and administer patient-centric interventions.

In South Africa, less than half of children receiving antiretroviral therapy are virally suppressed. Adherence challenges include poor palatability of drugs and high pill burden. Subcutaneous implants offer a long-acting alternative to daily oral dosing regimens, which may improve outcomes in children living with HIV (CLWH). Qualitative in-depth interviews were conducted with 24 health care providers (HCPs) in Johannesburg, South Africa. Interviews were audio-recorded and transcribed. Data were coded and analyzed using NVivo 12 software and a Grounded Theory approach. Most HCPs welcomed an implant option for CLWH. Perceived benefits included fewer clinic visits, improved adherence, and "normalization" of the lives of CLWH. Concerns included painful insertion and removal, the potential for stigmatization, and caregivers' likely rejection of biodegradable implants. A single, small, non-transparent rod with some flexibility was preferred by most participants. HCP training and early outreach to mitigate potential misinformation about implants and caregivers' fears about biodegradable implants were emphasized. Further engagement with caregivers of CLWH is required and ongoing.

Doravirine (DOR) concentrations and HIV-1 RNA were evaluated in genital fluids from adults with HIV on stable therapy who switched to DOR + FTC/TAF. High protein-unbound DOR concentrations were observed in both seminal plasma and cervicovaginal fluid. DOR + FTC/TAF maintained viral suppression in genital fluids in all but 1 participant.

BACKGROUND: Persons with acute HIV infection (AHI) are highly infectious and responsible for a disproportionate share of incident infections. Immediate antiretroviral therapy (ART) rapidly reduces blood viral loads (VL), but genital VLs after ART initiation during AHI are less well described. SETTING: Lilongwe, Malawi, 2012–2014. METHODS: HIV-seronegative and -serodiscordant persons ≥18 years were screened for AHI (RNA positive), and randomized to standard care, behavioral intervention, or behavioral intervention plus short-term ART (raltegravir/emtricitabine/tenofovir) (1:2:2). Persons who were ART eligible under Malawi guidelines could receive first-line therapy. Blood and genital VLs were assessed at weeks 1, 4, 8, and 12. Fisher’s Exact test was used to compare viral suppression by ART status. RESULTS: 46 persons with AHI enrolled, 17 of whom started ART within 12 weeks. Median blood VL at AHI diagnosis was 836,115 copies/mL. At week 12, 7% (1/14) of those who initiated ART had a blood VL ≥400 copies/mL, compared to 100% (23/23; p

Bictegravir (BIC), an integrase inhibitor, and doravirine (DOR), a non-nucleoside reverse transcriptase inhibitor, were recently approved by the US FDA for HIV treatment and are recommended first line treatment options. Because certain clinical scenarios warrant using them in combination, we developed a fully validated LC-MS/MS method for simultaneous measurement of BIC and DOR, along with a legacy integrase inhibitor, raltegravir (RAL), in human plasma over a clinically relevant 1000-fold range for each analyte. These analytes were extracted from the plasma by protein precipitation with their stable, isotopically labeled internal standards (BIC-d

BackgroundThe pharmacokinetics of bictegravir (BIC) and its association with the decay of human immunodeficiency virus (HIV)–1 RNA in genital fluids and the rectum have not yet been addressed.MethodsWe conducted a prospective, multicenter study of antiretroviral-naive people living with HIV-1 and initiating BIC/emtricitabine (FTC)/tenofovir alafenamide (TAF). HIV-1 RNA was measured (limit of quantification, 40 copies/mL) in blood plasma (BP), seminal plasma (SP), rectal fluid (RF), and cervicovaginal fluid (CVF) at baseline; Days 3, 7, 14, and 28; and Weeks 12 and 24. Total and protein-unbound BIC concentrations at 24 hours postdose (C24h) were quantified in BP, SP, CVF and rectal tissue (RT) on Day 28 and Week 12 using a validated liquid chromatography-tandem mass spectrometry assay.ResultsThe study population comprised 15 males and 8 females. In SP, RF, and CVF, the baseline HIV-1 RNA was >40 copies/mL in 12/15, 13/15, and 4/8 individuals, respectively, with medians of 3.54 (2.41–3.79), 4.19 (2.98–4.70), and 2.56 (1.61–3.56) log10 copies/mL, respectively. The initial decay slope was significantly lower in SP than in RF and BP. The time to undetectable HIV-1 RNA was significantly shorter in SP and RF than in BP. All women achieved undetectable HIV-1 RNA in CVF at Day 14. The median total BIC concentrations in SP, RT, and CVF were 65.5 (20.1–923) ng/mL, 74.1 (6.0–478.5) ng/g, and 61.6 (14.4–1760.2) ng/mL, respectively, representing 2.7%, 2.6%, and 2.8% of the BP concentration, respectively, while the protein-unbound fractions were 51.1%, 44.6%, and 42.6%, respectively.ConclusionsBIC/FTC/TAF led to rapid decay of HIV-1 RNA in genital and rectal fluids. Protein-unbound BIC concentrations in SP, RT, and CVF highly exceeded the half-maximal effective concentration (EC50) value (1.1 ng/mL).Clinical Trials RegistrationEudraCT 2018-002310-12.

Overlap in metabolism pathways of endogenous female sex hormones and antiretroviral drugs may lead to altered exposure to these compounds. In a family planning clinic in Lilongwe, Malawi, blood, blood cell, and cervicovaginal fluid (CVF) samples from seventy-three HIV positive Malawian women taken in follicular and luteal menstrual phases were assessed for estradiol and progesterone by chemiluminescent immunoassay, and for antiretroviral concentration by liquid chromatography-mass spectrometry. In both follicular and luteal phases, estradiol concentrations were lower in women receiving efavirenz compared with women on non-efavirenz regimens or no antiretroviral therapy (p

The "shock and kill" strategy for HIV-1 cure incorporates latency-reversing agents (LRA) in combination with interventions that aid the host immune system in clearing virally reactivated cells. LRAs have not yet been investigated in pediatric clinical or preclinical studies. Here, we evaluated an inhibitor of apoptosis protein (IAP) inhibitor (IAPi), AZD5582, that activates the noncanonical NF-κB (ncNF-κB) signaling pathway to reverse latency. Ten weekly doses of AZD5582 were intravenously administered at 0.1 mg/kg to rhesus macaque (RM) infants orally infected with SIV

Non-human primates (NHP) are widely used for the pre-clinical assessment of antiretrovirals (ARVs) for HIV treatment and prevention. However, the utility of these models is questionable given the differences in ARV pharmacology between humans and macaques. Here, we report a model based on

Background Islatravir (4′-ethynyl-2-fluoro-2′-deoxyadenosine; EFdA) is a first-in-class nucleoside reverse transcriptase translocation inhibitor (NRTTI) being investigated for HIV treatment and prevention. EFdA is intracellularly phosphorylated to EFdA-triphosphate (EFdA-tp), a competitive substrate of deoxyadenosine-triphosphate (dATP). Thus, translating safety and efficacy findings from preclinical studies relies on the assumption that EFdA’s intracellular pharmacology can be extrapolated across species. Objectives We investigated how EFdA is phosphorylated across animal species commonly used for preclinical models in drug development to identify those that most closely matched humans. Methods PBMCs were isolated from whole blood of six species (human, rhesus macaque non-human primate (rmNHP), rat, minipig, dog, and rabbit) using Ficoll separation and counted on a haemocytometer by Trypan blue staining. One million live cells were cultured in media supplemented with 10 U/mL human IL-2, 10% FBS and 1% antibiotics and treated with 0, 17, 170, and 1700 nM EFdA (n = 3 replicates per concentration). After 24 h, representative cell counts were derived from untreated control wells (as above), cells were washed in PBS, and lysed with 70:30 methanol:water. EFdA-tp and dATP concentrations were quantified by HPLC-MS/MS and normalized to the representative live cell counts for each species. Results When compared to human values, EFdA-tp concentrations for each EFdA treatment concentration were lower in all species (rmNHP 1.5–2.1-fold, rat 4.5–15-fold, minipig 37–71-fold, dog and rabbit >100-fold). Additionally, rmNHP and dog PBMCs exhibited significantly higher (7–10-fold; P < 0.001) dATP when compared with human PBMCs. Conclusions Given intracellular pharmacology differences, these preclinical models may be a conservative estimate of EFdA’s intracellular pharmacokinetics and efficacy in humans.

Feminizing hormone therapy (FHT) may interact with human immunodeficiency virus preexposure prophylaxis (PrEP). We found that transgender women who took FHT exhibited a 7-fold lower rectal tissue ratio of PrEP’s active metabolites vs competing deoxynucleotides compared to cisgender women and men (P = .03) that inversely correlated with estradiol (ρ = –0.79; P < .05). Thus, FHT may negatively impact PrEP efficacy. Clinical Trials Registration . NCT02983110.

Despite development of modern antiretrovirals with lower drug interaction potential than their predecessors, drug interaction challenges remain. Standard treatment regimens still require multiple antiretrovirals that may cause, or may be the target of, drug interactions. Additionally, people living with HIV are living longer and often present with comorbid conditions that require concomitant long-term drug therapy. Also, treatment of infectious diseases in resource-limited settings can result in significant interactions. In this review, we describe absorption, distribution, metabolism, and excretion pathways as they relate to relevant drug interactions with antiretrovirals along with the potential clinical consequences of these interactions. We highlight clinical data that illustrate pertinent interactions and provide tools to assist in predicting drug interactions in the absence of clinical data. Given these tools and thoughtful consideration of drug combinations, drug therapy in people living with HIV can be safely and effectively managed throughout their lifetime.

Lack of adherence is a key barrier to a successful human immunodeficiency virus (HIV) treatment and prevention. We report on an ultra-long-acting (ULA) biodegradable polymeric solid implant (PSI) that can accommodate one or more antiretrovirals (e.g., dolutegravir (DTG) and rilpivirine (RPV)) at translatable human doses (65% wt.) in a single implant. PSIs are fabricated using a three-step process: (a) phase inversion of a drug/polymer solution to form an initial in-situ forming solid implant, (b) micronization of dried drug-loaded solid implants, and (c) compression of the micronized drug-loaded solid powder to generate the PSI. DTG and RPV can be pre-combined in a single PLGA-based solution to make dual-drug PSI; or formulated individually in PLGA-based solutions to generate separate micronized powders and form a bilayer dual-drug PSI. Results showed that in a single or bilayer dual-drug PSI, DTG and RPV exhibited physicochemical properties similar to their pure drug analogues. PSIs were well tolerated in vivo and effectively delivered drug(s) over 180 days with concentrations above 4 × PA-IC90 after a single subcutaneous administration. While biodegradable and do not require removal, these PSIs can safely be removed to terminate the treatment if required. The versatility of this technology makes it attractive as an ULA drug delivery platform for HIV and various therapeutic applications.

Women worldwide confront two major reproductive health challenges: the need for contraception and protection from sexually transmitted infections, including Human Immunodeficiency Virus (HIV). Multipurpose Prevention Technologies (MPTs) that simultaneously prevent unintended pregnancy and HIV could address these challenges with a single product. Here, we developed a long-acting (LA) subcutaneously administered and biodegradable implant system that provides sustained delivery of contraceptive and antiretroviral (ARV) with zero-order release kinetics. The MPT system involves two implants comprising an extruded tube of a biodegradable polymer, poly(e-caprolactone) (PCL). Each implant is filled with a formulation of progestin [levonorgestrel (LNG) or etonogestrel (ENG)], or a formulation of a potent ARV [tenofovir alafenamide (TAF), or 4′-Ethynyl-2-fluoro-2′-deoxyadenosine (EFdA)]. We demonstrated sustained in-vitro release of LNG, ENG, and EFdA from the implant system for 13–17 months, while maintaining high stability of the drugs (>99%) within the implant reservoirs. We further elucidated the controlled release mechanism of the implant and leveraged several tunable parameters (e.g., type and quantity of the excipient, PCL properties, and implant wall thickness) to tailor the release kinetics and enhance the mechanical integrity of the MPT implant. The optimized MPT showed sustained in-vitro release of ENG and EFdA over 1 year while maintaining a high level of formulation stability and structural integrity. The MPT implant system was further evaluated in a preclinical study using a rodent model and demonstrated sustained release of EFdA (6 months) and ENG (12 months) with high stability of the drug formulation (>95%). This manuscript supports the continued advancement of LA delivery systems for MPTs.

Supplemental Digital Content is Available in the Text., Objective: To describe and compare systemic and local pharmacokinetics (PK) and cervicovaginal (CV) pharmacodynamics (PD) of oral tenofovir disoproxil fumarate (TDF) in combination with emtricitabine (FTC) with tenofovir (TFV) intravaginal ring (IVR). Design: Phase I, randomized, parallel-group study. Women (n = 22) used TDF/FTC oral tablets daily or TFV IVR continuously and were assessed at baseline and 14 days. Methods: TFV and FTC concentrations were measured in plasma, CV fluid (CVF), and CV tissue. TFV-diphosphate and FTC-triphosphate were assessed in CV tissue. In vitro PD antiviral activities of TFV and FTC (using in vivo concentration ranges) were modeled in the CVF and by infecting CV tissue explants ex vivo with HIV-1BaL. Results: Adverse events (AEs) were more common with oral TDF/FTC use (P < 0.01). The median CVF TFV concentrations were 106 ng/mL after use of TFV IVR vs. 102 ng/mL for TDF/FTC. The median TFV and TFV-diphosphate concentrations in CV tissue were >100-fold higher among IVR users. The median CVF FTC concentrations were 103 ng/mL. FTC and FTC-triphosphate were detected in all CV tissues from TDF/FTC users. HIV inhibitory activity of CVF increased significantly with treatment in both cohorts (P < 0.01) but was higher in TFV IVR users (P < 0.01). In vitro inhibition of tissue infection with ex vivo administration of TFV and FTC was dose dependent, with maximal efficacy achieved with 10 µg/mL TFV, 1 µg/mL FTC, and 0.1 µg/mL of TFV and FTC combined. Conclusions: Both products were safe and increased mucosal HIV inhibitory activity. In addition to systemic protection, oral TDF/FTC displays a PK/PD profile compatible with CV mucosal antiviral activity. TFV IVR resulted in fewer AEs, lower TFV plasma concentrations, higher CVF and tissue TFV and TFV-DP concentrations, and greater anti-HIV activity in CVF.

Background Daily oral emtricitabine (FTC, F)/tenofovir disoproxil fumarate (TDF) combination is approved for HIV pre-exposure prophylaxis (PrEP) in men and women. Tenofovir alafenamide fumarate (TAF) is a newer, more potent prodrug of tenofovir (TFV), and in combination with FTC, has recently been approved for prevention of HIV through rectal transmission. Methods This Phase I, prospective, interventional, randomized study was conducted in three clinical sites: PROFAMILIA, Santo Domingo, Dominican Republic; University of Pittsburgh and Eastern Virginia Medical School. We assessed the multi-compartmental pharmacokinetics (primary outcome) and safety (secondary outcome) among HIV uninfected women randomized to F/TDF (200mg/300mg) or F/TAF (200mg/25mg; F/TAF25) (n=24) in a single dose phase (SDP) and F/TDF, F/TAF (200mg/10mg; F/TAF10), or F/TAF25 (n=75) in a multiple dose (14 daily doses) phase (MDP). We described PK parameters in plasma, peripheral blood mononuclear cells (PBMCs), and cervicovaginal (CV) and rectal fluids and tissues. ClinicalTrials.gov #NCT02904369, completed. Findings Recruitment for the study began on 5 October 2016. The first participant was enrolled on 6 October 2016 and the last participant completed the study 21 November 2017. Plasma TFV concentrations area under curve (AUC) were ~20 fold lower following F/TAF versus F/TDF. TFV-diphosphate (TFV-DP) AUC concentrations in PBMCs were 7-fold higher with F/TAF25 versus F/TDF. Median TFV-DP concentrations in vaginal tissue (4hours post last dose) were approximately 6-fold higher with F/TAF25 versus F/TDF. TFV and TFV-DP were lower with F/TAF versus F/TDF in rectal tissue. Concentrations of FTC and FTC-triphosphate (FTC-TP) were similar across matrices and treatment arms. Gastrointestinal adverse events (AEs) occurred more frequently in F/TDF users (44.0%) than in either F/TAF group (11.5 and 12.0%). Interpretation F/TAF was safe and well-tolerated. TFV-DP concentrations were higher in PBMCs and similar or higher (4h post dose) in female genital tract tissues for F/TAF versus F/TDF. High FTC and FTC-TP concentrations in all compartments support the potential of F/TAF as a new PrEP combination for women. Funding United States Agency for International Development (USAID)/the President's Emergency Plan for AIDS Relief (PEPFAR) through Cooperative Agreement AID-OAA-A-14-00011 with CONRAD/Eastern Virginia Medical School. This publication resulted in part from research supported by the University of North Carolina at Chapel Hill Center for AIDS Research (CFAR).

Brincidofovir (BCV) is an investigational lipid conjugate of the nucleotide analog cidofovir (CDV), which is being developed as a medical countermeasure for the treatment of smallpox. BCV is active against double-stranded DNA viruses including BK and JC viruses. Here, we validated procedures for quantifying BCV and its pharmacologically active moiety cidofovir diphosphate (CDV-PP) in mouse kidney, brain and spleen tissue homogenates. Following homogenization, BCV and CDV-PP were extracted from the tissues by protein precipitation with their stable, isotopically labeled internal standards, BCV-d6 and 13 C3 15 N2 -CDV-PP. Then, samples were analyzed for BCV by reverse-phase chromatography on a Waters Xterra MS C18 (50 × 2.1 mm, 3.5 μm particle size) column while CDV-PP was analyzed on a Thermo BioBasic AX (50 × 2.1 mm, 5 μm particle size) column using anion exchange chromatography. Detection was achieved by electrospray ionization in positive ion mode on an AB Sciex API-5000 triple quadrupole mass spectrometer. The calibration curves were linear over a range of 1.00-1,000 ng/ml homogenate and 0.050-50.0 ng/ml homogenate for BCV and CDV-PP, respectively. These methods were validated according to US Food and Drug Administration guidance for industry and may be used to characterize the tissue pharmacology of both analytes to advance its preclinical development.

Despite significant advances in HIV treatment over the past 30 years, critical barriers to an HIV cure persist. The HIV reservoir, defined at both the cellular and anatomical level, constitutes the main barrier to cure. While the mechanisms underlying the reservoir are not yet well understood, one theory to explain persistence at the anatomical level is that subtherapeutic exposure to antiretroviral therapy (ART) within certain tissue compartments permits ongoing replication. Characterizing ART pharmacology throughout the body is important in the context of these potential pharmacologic sanctuaries and for maximizing the probability of success with forthcoming cure strategies that rely on latency reversal and require ART to prevent reseeding the reservoir. In this review, we provide a comprehensive overview of ART and latency reversal agent distribution at the site of action for HIV cure (i.e., anatomical sites commonly associated with HIV persistence, such as lymphoid organs and the central nervous system). We also discuss methodologic approaches that provide insight into HIV cure pharmacology, including experimental design and advances within the computational, pharmaceutical, and analytical chemistry fields. The information discussed in this review will assist in streamlining the development of investigational cure strategies by providing a roadmap to ensure therapeutic exposure within the site of action for HIV cure.

We have developed a macromolecular prodrug platform based on poly(l-lysine succinylated) (PLS) that targets scavenger receptor A1 (SR-A1), a receptor expressed by myeloid and endothelial cells. We demonstrate the selective uptake of PLS by murine macrophage, RAW 264.7 cells, which was eliminated upon cotreatment with the SR-A inhibitor polyinosinic acid (poly I). Further, we observed no uptake of PLS in an SR-A1-deficient RAW 264.7 cell line, even after 24 h incubation. In mice, PLS distributed to lymphatic organs following i.v. injection, as observed by ex vivo fluorescent imaging, and accumulated in lymph nodes following both i.v. and i.d. administrations, based on immunohistochemical analysis with high-resolution microscopy. As a proof-of-concept, the HIV antiviral emtricitabine (FTC) was conjugated to the polymer's succinyl groups via ester bonds, with a drug loading of 14.2% (wt/wt). The prodrug (PLS-FTC) demonstrated controlled release properties in vitro with a release half-life of 15 h in human plasma and 29 h in esterase-inhibited plasma, indicating that drug release occurs through both enzymatic and nonenzymatic mechanisms. Upon incubation of PLS-FTC with human peripheral blood mononuclear cells (PBMCs), the released drug was converted to the active metabolite FTC triphosphate. In a pharmacokinetic study in rats, the prodrug achieved ∼7-19-fold higher concentrations in lymphatic tissues compared to those in FTC control, supporting lymphatic-targeted drug delivery. We believe that the SR-A1-targeted macromolecular PLS prodrug platform has extraordinary potential for the treatment of infectious diseases.

Bictegravir (BIC), an integrase inhibitor, and doravirine (DOR), a non-nucleoside reverse transcriptase inhibitor, were recently approved by the US FDA for HIV treatment and are recommended first line treatment options. Because certain clinical scenarios warrant using them in combination, we developed a fully validated LC-MS/MS method for simultaneous measurement of BIC and DOR, along with a legacy integrase inhibitor, raltegravir (RAL), in human plasma over a clinically relevant 1000-fold range for each analyte. These analytes were extracted from the plasma by protein precipitation with their stable, isotopically labeled internal standards (BIC-d5, 13C6-DOR, and RAL-d6). Following extraction, samples were analyzed by reverse phase chromatography on a Waters Atlantis T3 C18 (50×2.1mm, 3um particle size) column with subsequent detection by electrospray ionization in positive ion mode on an AB Sciex API-5000 triple quadrupole mass spectrometer. The assay was linear (R2>0.994) over the selected calibration ranges (20.0-20,000ng/mL (BIC), 3.00-3,000ng/mL (DOR), and 10.0-10,000 (RAL)). The assay was accurate (inter-assay %Bias ≤±8.5) and precise (inter-assay %CV ≤11.4). This method was validated according to FDA guidance for industry and can be used to assess the pharmacokinetics of two newly approved antiretrovirals, or to support therapeutic drug monitoring for modern antiretroviral therapy.

BACKGROUND: The majority of HIV-infected cells during antiretroviral therapy (ART) persist in lymphoid tissues. Studies disagree on whether suboptimal tissue ART concentrations contribute to ongoing HIV replication during viral suppression. METHODS: We performed a cross-sectional study in virally-suppressed HIV+ participants measuring lymphoid tissue ART (darunavir [DRV], atazanavir [ATV], and raltegravir [RAL]) concentrations by LC-MS/MS assay. Tissue and plasma ART concentrations were used to estimate tissue:plasma penetration ratios (TPRs) as well as drug-specific tissue:inhibitory concentration ratios (TICs). HIV DNA and sequentially-produced HIV RNA transcripts were quantified from rectal biopsies using droplet digital PCR (ddPCR) assays. RESULTS: Tissue samples were collected in duplicate from 19 participants: 38 rectal, 8 ileal (4 RAL, 2 DRV, 2 ATV), and 6 lymph node (4 RAL, 2 DRV) samples. Overall, median TICs were higher for RAL than DRV or ATV (both P=0.006). Median TICs were lower in lymph nodes vs. ileum (0.49 vs. 143, P=0.028) or rectum (33, P=0.019), and all ART levels were below target concentrations. Higher rectal TICs were associated with lower HIV RNA transcripts (read-through, long LTR, and Nef, P all

The antiretroviral drug rilpivirine was developed into a long-acting formulation (RPV LA) to improve adherence for preexposure prophylaxis (PrEP) to prevent HIV-1 transmission. A concern is that RPV LA will not inhibit transmission of drug-resistant HIV-1 and may select for drug-resistant virus. In female humanized mice, we found that RPV LA inhibited vaginal transmission of WT or 3-fold RPV-resistant HIV-1 but not virus with 30-fold RPV resistance. In animals that became infected despite RPV LA PrEP, WT HIV-1 dissemination was delayed until genital and plasma RPV concentrations waned. RPV resistance was detected at similar low frequencies in untreated and PrEP-treated mice that became infected. These results indicate the importance of maintaining RPV at a sustained threshold after virus exposure to prevent dissemination of HIV-1 after vaginal infection and low-frequency resistance mutations conferred low-level resistance, suggesting that RPV resistance is difficult to develop after HIV-1 infection during RPV LA PrEP., As a long-acting formulation of the nonnucleoside reverse transcriptase inhibitor rilpivirine (RPV LA) has been proposed for use as preexposure prophylaxis (PrEP) and the prevalence of transmitted RPV-resistant viruses can be relatively high, we evaluated the efficacy of RPV LA to inhibit vaginal transmission of RPV-resistant HIV-1 in humanized mice. Vaginal challenges of wild-type (WT), Y181C, and Y181V HIV-1 were performed in mice left untreated or after RPV PrEP. Plasma viremia was measured for 7 to 10 weeks, and single-genome sequencing was performed on plasma HIV-1 RNA in mice infected during PrEP. RPV LA significantly prevented vaginal transmission of WT HIV-1 and Y181C HIV-1, which is 3-fold resistant to RPV. However, it did not prevent transmission of Y181V HIV-1, which has 30-fold RPV resistance in the viruses used for this study. RPV LA did delay WT HIV-1 dissemination in infected animals until genital and plasma RPV concentrations waned. Animals that became infected despite RPV LA PrEP did not acquire new RPV-resistant mutations above frequencies in untreated mice or untreated people living with HIV-1, and the mutations detected conferred low-level resistance. These data suggest that high, sustained concentrations of RPV were required to inhibit vaginal transmission of HIV-1 with little or no resistance to RPV but could not inhibit virus with high resistance. HIV-1 did not develop high-level or high-frequency RPV resistance in the majority of mice infected after RPV LA treatment. However, the impact of low-frequency RPV resistance on virologic outcome during subsequent antiretroviral therapy still is unclear. IMPORTANCE The antiretroviral drug rilpivirine was developed into a long-acting formulation (RPV LA) to improve adherence for preexposure prophylaxis (PrEP) to prevent HIV-1 transmission. A concern is that RPV LA will not inhibit transmission of drug-resistant HIV-1 and may select for drug-resistant virus. In female humanized mice, we found that RPV LA inhibited vaginal transmission of WT or 3-fold RPV-resistant HIV-1 but not virus with 30-fold RPV resistance. In animals that became infected despite RPV LA PrEP, WT HIV-1 dissemination was delayed until genital and plasma RPV concentrations waned. RPV resistance was detected at similar low frequencies in untreated and PrEP-treated mice that became infected. These results indicate the importance of maintaining RPV at a sustained threshold after virus exposure to prevent dissemination of HIV-1 after vaginal infection and low-frequency resistance mutations conferred low-level resistance, suggesting that RPV resistance is difficult to develop after HIV-1 infection during RPV LA PrEP.

Background This study assessed the penetration and efficacy of tenofovir alafenamide (TAF) in the male genital tract (MGT) and the semen quality of individuals infected with human immunodeficiency virus (HIV)-1 who were treated with a TAF-containing regimen. Methods This was a prospective, open-label, single-arm study of 14 virologically-suppressed, HIV-1–infected men on stable antiretroviral therapy with elvitegravir, cobicistat, emtricitabine (E/C/F) and tenofovir disoproxil fumarate (TDF) who switched to E/C/F and TAF. At baseline (pre-switch) and at 12 weeks post-switch, we measured HIV-1 RNA in seminal plasma (SP) and blood plasma (BP), tenofovir (TFV) in SP and BP, and TFV-diphosphate (dp) in peripheral blood mononuclear cells (PBMCs) and seminal mononuclear cells (SMCs) at the end of the dosing interval (C24h). Semen quality was assessed before switching and after 12 weeks on TAF. Results With TAF, TFV C24 was 11.9-fold higher in SP than in BP. This concentration was significantly lower than TFV C24 in SP with TDF, but 9.6-fold higher than the 50% inhibitory concentration (IC50) (11.5 ng/mL). By contrast, the median TFV-dp concentration achieved with TAF in SMCs was 6% that of TFV-dp in PBMCs. The TFV-dp SMC:PBMC ratio was also significantly lower with TAF. Nonetheless, TFV-dp C24 in SMC was comparable with TAF and TDF. All the patients had HIV-1 RNA Conclusions Extracellular and intracellular seminal TFV distribution differs between TAF and TDF. Nevertheless, both formulations, combined with elvitegravir/cobicistat/emtricitabine, maintained HIV-1 RNA suppression in semen. Differences in MGT distribution were not associated with differences in semen quality. Clinical Trials Registration EudraCT: 2016-001371-69

The goal of this work was to evaluate dosing strategies for tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF), and emtricitabine (FTC) for pre-exposure prophylaxis (PrEP) with injection drug use with a pharmacokinetic/pharmacodynamics analysis of concentration data generated from two single-dose clinical studies conducted in healthy women. Population pharmacokinetic models were developed using measured intracellular metabolite, endogenous nucleotide competitors, and extracellular parent drug concentrations. Intracellular metabolite concentrations were normalized to endogenous competitors and compared with an EC(90) target for PrEP efficacy. Monte Carlo simulations were used to select effective dose strategies of single agents (TAF, TDF, and FTC) and combinations (TDF + FTC and TAF + FTC). Daily, intermittent, and event-driven dosing regimens at varying dosage amounts were explored. When combined, TDF + FTC and TAF + FTC both provided quick (0.5 hours) and durable (up to 84 and 108 hours, respectively) protection of ≥99% after a single dose. When dosed twice per week, protection remained at 100%. Single-agent regimens provided lower estimates of protection than either combination tested. Here, the application of pharmacokinetic modeling to in vitro target concentrations demonstrates the added utility of including FTC in a successful PrEP regimen. While no TAF-based PrEP data are currently available for comparison, this analysis suggests TAF + FTC could completely protect against percutaneous exposure with as little as two doses per week.

Preexposure prophylaxis (PrEP) is a powerful tool that, as part of a comprehensive prevention package, has potential to significantly impact the HIV epidemic. PrEP effectiveness is believed to be dependent on the exposure and efficacy of antiretrovirals at the site of HIV transmission. Clinical trial results as well as modeling and simulation indicate the threshold of adherence required for PrEP efficacy of emtricitabine/tenofovir disoproxil fumarate may differ between sites of HIV transmission with less forgiveness for missed doses in women exposed through genital tissue compared to people exposed through colorectal tissue. This suggests a role for local and host factors to influence mucosal pharmacology. Here we review the mucosal pharmacology of antiretrovirals in the female genital tract and explore potential determinants of PrEP efficacy. Host factors such as inflammation, coinfections, hormonal status, and the vaginal microbiome will be explored as well as the role of drug-metabolizing enzymes and transporters in regulating local drug exposure. The use of preclinical and early clinical models to predict clinical effectiveness is also discussed.

Supplemental Digital Content is Available in the Text., Objective: We describe and compare the local and systemic pharmacokinetics (PK) of tenofovir (TFV) and TFV-diphosphate (TFV-DP) in healthy premenopausal (PRE) and postmenopausal (POST) women using TFV 1% gel and correlate local PK with other mucosal end points. Methods: PRE (n = 20) and POST (n = 17) women used 2 doses of TFV 1% vaginal gel, separated by 2 hours. Blood and cervicovaginal samples were obtained 3 and 23 hours after the second dose. PRE women used gel in the follicular and luteal phases of the menstrual cycle. POST women used gel at baseline and again after approximately 2 months of treatment with 0.01% vaginal estradiol (E2) cream. Results: Median TFV concentrations in cervicovaginal aspirate (ng/mL) and vaginal tissue (ng/mg) were significantly higher in PRE (4.3E106, 49.8) versus POST women (2.6E106, 2.2). POST women had significantly higher median molecular ratios of TFV-DP to TFV (3.7%) compared with PRE (0.19%). After vaginal E2 treatment, the local and systemic PK end points in POST women were generally similar to PRE women (all P values > 0.05). Importantly, median vaginal tissue TFV-DP concentrations (fmol/mg) among PRE, POST, and POST women after E2 therapy were similar (292.5, 463.3, and 184.6, respectively). Vaginal tissue TFV concentrations were significantly positively correlated with vaginal epithelial thickness, whereas vaginal tissue TFV-DP concentrations were positively correlated with density of vaginal CD4+ and CD8+ immune cells. Conclusions: The state of the cervicovaginal mucosa has a significant impact on local and systemic PK of a topically applied microbicide.

Background Cancer is a leading cause of death in HIV-infected patients in the era of combination antiretroviral therapy (cART). Yet, there are no specific guidelines for the combined use of cART and chemotherapy in HIV-infected cancer patients. The cellular enzyme thymidylate synthase (TS) catalyses the conversion of dUMP to TMP, which is converted to TDP and ultimately to TTP, a building block in DNA synthesis. TS inhibitors are recommended in some cancers, particularly non-small cell lung cancer (NSCLC). Because TS inhibitors modulate intracellular concentrations of endogenous 2′-deoxynucleotides, we hypothesized that TS inhibitors could impact the anti-HIV activity of nucleoside analogue reverse transcriptase inhibitors (NRTIs). Methods We evaluated gemcitabine and pemetrexed, two approved TS inhibitors, on the anti-HIV activities of NRTIs in infectivity assays using peripheral blood mononuclear cells (PBMCs) and in humanized mice. Results Gemcitabine enhanced the anti-HIV activities of tenofovir, abacavir and emtricitabine (FTC) in PBMCs. In contrast, pemetrexed had no effect on tenofovir, enhanced abacavir and, unexpectedly, decreased FTC and lamivudine (3TC) activities. Pemetrexed inhibitory effects on FTC and 3TC may be due to lower concentrations of active metabolites (FTCtp and 3TCtp) relative to their competing endogenous nucleotide (dCTP), as shown by decreases in FTCtp/dCTP ratios. Gemcitabine enhanced tenofovir while pemetrexed abrogated FTC antiviral activity in humanized mice. Conclusions Chemotherapy with TS inhibitors can have opposing effects on cART, potentially impacting control of HIV and thereby development of viral resistance and size of the reservoir in HIV-infected cancer patients. Combinations of cART and chemotherapy should be carefully selected.

The ability to monitor adherence to antiretroviral therapy is critical for the interpretation of outcomes from clinical studies of HIV, and for optimizing patient care. The antiretrovirals tenofovir (TFV), emtricitabine (FTC), and lamivudine (3TC) are commonly included in drug regimens for HIV prevention and treatment. The active form of the drugs tenofovir diphosphate (TFVdp), emtricitabine triphosphate (FTCtp), and lamivudine triphosphate (3TCtp) are found intracellularly in erythrocytes and peripheral blood mononuclear cells (PBMCs). The ability to collect and analyze dried blood spot (DBS) samples is an attractive alternative to PBMC sampling in many resource limited settings. We developed and validated an assay to quantify all three intracellular metabolites over the range of 100–25000 fmol/sample. This assay utilizes a simple protein precipitation/liquid-liquid extraction of a single 3-mm DBS punch (from a Whatman 903 Protein Saver card) with isotopically labeled 13C5-TFVdp included as the internal standard. Following extraction, samples are analyzed by anion exchange chromatography on a Thermo Biobasic AX 5micron column with detection by electrospray ionization in the positive mode on a AB Sciex API-5000 triple quadrupole mass spectrometer with a total run time of 8 minutes. The assay was linear over the entire range (R2>0.996). The assay was accurate (inter-assay %bias within ±3.0%) and precise (inter-assay %CV ≤9.8%). The assay was also reproducible from multiple punches within a spot as well as punches from separate blood spots. Stability was established at room temperature for 3 days, and at −80°C for up to 63 days. Clinical samples were analyzed from subjects on Truvada®, Stribild®, Descovy®, and Triumeq® regimens and intracellular metabolites were detected in all samples as expected, indicating the assay performs well for all current formulations of TFV, FTC, and 3TC.

Objectives: Tenofovir alafenamide, a prodrug of tenofovir, produces higher PBMC concentrations of tenofovir diphosphate (tenofovir-dp) than tenofovir disoproxil fumarate. To understand tenofovir alafenamide’s mucosal tissue distribution and its implications for pre-exposure prophylaxis, we characterized tenofovir-dp in female genital tract (FGT) and lower gastrointestinal (GI) tissues. Methods: Healthy seronegative women were given 5, 10 or 25 mg of tenofovir alafenamide (n = 8/group). Each participant provided plasma, PBMC and cervical, vaginal and rectal tissue samples over 14 days. Plasma, cell lysate and tissue homogenate concentrations were analysed by LC-MS/MS. Dose proportionality was declared in plasma and PBMCs if the natural log AUC versus natural log dose regression line 90% CI was within 0.57–1.43. In vitro tenofovir-dp formation was assessed in PBMCs and ectocervical (Ect1/E6E7) and vaginal (VK2/E6E7) cells incubated in 0.5 and 10 μM tenofovir alafenamide or tenofovir. clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT02357602","term_id":"NCT02357602"}}NCT02357602. Results: Following single doses of 5, 10 and 25 mg, median (IQR) tenofovir plasma AUC0–14 days was 52.8 (49.5–59.6), 78.1 (68.2–86.9) and 169.7 (131.2–211.4) ng·h/mL and tenofovir-dp PBMC AUC0–14 days was 2268 (1519–4090), 4584 (3113–5734) and 9306 (6891–10785) fmol·h/106 cells, respectively. Tenofovir was quantifiable in 52% and 92% of FGT and GI tissues, whereas tenofovir-dp was quantifiable in only 5% and 19% of FGT and GI tissues, respectively. Plasma tenofovir and PBMC tenofovir-dp were dose proportional (90% CI = 0.87–1.15 and 0.62–1.02, respectively). In vitro tenofovir-dp was 1.7–17-fold higher in epithelial cells than PBMCs. Conclusions: After tenofovir alafenamide dosing in vivo, tenofovir-dp was unquantifiable in most tissues (91%) although cervical and vaginal epithelial cells efficiently formed tenofovir-dp from tenofovir alafenamide in vitro. These findings warrant further investigation of tenofovir alafenamide’s pharmacology.

Objectives: Our primary objective was to compare geometric mean levonorgestrel concentrations between levonorgestrel implant users who were or were not taking the antiretroviral efavirenz, for up to 30 months after implant initiation. Our secondary objective was to evaluate the pregnancy rate among levonorgestrel implant users on efavirenz. Study design: We performed a subanalysis of 42 Malawian women randomized to initiate the levonorgestrel implant as part of a parent randomized clinical trial. Our subset included 30 HIV-infected women taking efavirenz and 12 HIV-uninfected women not taking efavirenz. They underwent urine pregnancy testing every 3 months and serum levonorgestrel testing at day 3 and months 1, 3, 6, 12, 18, 24, 27 and 30 after implant initiation. Geometric mean levonorgestrel concentrations were calculated for efavirenz users and non-efavirenz users at each time point. Results: The geometric mean levonorgestrel concentrations were lower for efavirenz users than non-efavirenz users at every time point; the geometric mean ratio for efavirenz users:non-efavirenz users ranged from 0.60 [90% confidence interval (CI) 0.46–0.79] at 1 month to 0.27 (90% CI 0.12–0.61) at 30 months after implant insertion. No pregnancies occurred over 60 woman-years of concomitant levonorgestrel implant and efavirenz use, although 11 women had levonorgestrel concentrations

Here we report an ultra-long-acting tunable, biodegradable, and removable polymer-based delivery system that offers sustained drug delivery for up to one year for HIV treatment or prophylaxis. This robust formulation offers the ability to integrate multiple drugs in a single injection, which is particularly important to address the potential for drug resistance with monotherapy. Six antiretroviral drugs were selected based on their solubility in N-methyl-2-pyrrolidone and relevance as a combination therapy for HIV treatment or prevention. All drugs released with concentrations above their protein-adjusted inhibitory concentration and retained their physical and chemical properties within the formulation and upon release. The versatility of this formulation to integrate multiple drugs and provide sustained plasma concentrations from several weeks to up to one year, combined with its ability to be removed to terminate the treatment if necessary, makes it attractive as a drug delivery platform technology for a wide range of applications., Patient drug regime compliance is a major issue; sustained release implants could address this. Here, the authors report on a phase inverted in situ forming implant of PLGA for the sustained release of antiretroviral drugs and optimize and demonstrate the release of 6 different drugs over a period of up to a year.

Maraviroc-based regimens have been explored as preexposure prophylaxis (PrEP) against human immunodeficiency virus (HIV). In this study, we utilized mucosal tissue drug exposure data, combined with target concentrations generated in vitro, in a pharmacokinetic-pharmacodynamic analysis to predict the effects of drug combinations and adherence on PrEP efficacy. Mucosal tissue concentrations of maraviroc were measured in 24 healthy women. The 90% effective concentrations (EC(90)) of maraviroc (alone and combined with tenofovir and emtricitabine) for protection against HIV were identified in CD4(+) T cells. Monte Carlo simulations were performed to identify dosing strategies to protect colorectal and female genital tract (FGT) tissues from HIV infection. Colorectal maraviroc concentrations were 350-fold higher than in the FGT. Under steady-state conditions, our model predicted that one 300-mg dose/week was sufficient to protect colorectal tissue from HIV in 99% of the population, while 300 mg daily would protect the FGT in only 63% of the population. FGT protection increased to >90% when maraviroc was used in combination with tenofovir (5 doses/week) or emtricitabine (3 doses/week). Poor adherence resulted in a drastic decrease in efficacy in the FGT but not colorectal tissue. However, greater forgiveness was seen when maraviroc was combined with tenofovir or emtricitabine, suggesting that maraviroc should not be used alone as PrEP.