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The blood-brain barrier (BBB) is a protective cellular anatomical layer with a dynamic micro-environment, tightly regulating the transport of materials across it. To achieve in-vivo characteristics, an in-vitro BBB model requires the constituent cell types to be layered in an appropriate order. A cost-effective in-vitro BBB model is desired to facilitate central nervous system (CNS) drug penetration studies. Enhanced integrity of tight junctions observed during the in-vitro BBB establishment and post-experiment is essential in these models. We successfully developed an in-vitro BBB model mimicking the in-vivo cell composition and a distinct order of seeding primary human brain cells. Unlike other in-vitro BBB models, our work avoids the need for pre-coated plates for cell adhesion and provides better cell visualization during the procedure. We found that using bovine collagen-I coating, followed by bovine fibronectin coating and poly- L -lysine coating, yields better adhesion and layering of cells on the transwell membrane compared to earlier reported use of collagen and poly- L -lysine only. Our results indicated better cell visibility and imaging with the polyester transwell membrane as well as point to a higher and more stable Trans Endothelial Electrical Resistance values in this plate. In addition, we found that the addition of zinc induced higher claudin 5 expressions in neuronal cells. Dolutegravir, a drug used in the treatment of HIV, is known to appear in moderate concentrations in the CNS. Thus, dolutegravir was used to assess the functionality of the final model and cells. Using primary cells and an in-house coating strategy substantially reduces costs and provides superior imaging of cells and their tight junction protein expression. Our 4-cell-based BBB model is a suitable experimental model for the drug screening process. • A cost-effective in-vitro BBB model is desired for CNS drug penetration studies. • Addition of zinc induces higher claudin 5 expressions in neuronal cells. • Dolutegravir was used to assess the functionality of the final model and cells. • Primary cells and coating strategy reduces costs and provides superior cell imaging. • 4-cell-based BBB model is suitable for the drug screening process. [ABSTRACT FROM AUTHOR]

Antiretroviral therapy can reduce HIV-1 to undetectable levels in peripheral blood, but the effectiveness of treatment in suppressing replication in lymphoid tissue reservoirs has not been determined. Here we show in lymph node samples obtained before and during 6 mo of treatment that the tissue concentrations of five of the most frequently used antiretroviral drugs are much lower than in peripheral blood. These lower concentrations correlated with continued virus replication measured by the slower decay or increases in the follicular dendritic cell network pool of virions and with detection of viral RNA in productively infected cells. The evidence of persistent replication associated with apparently suboptimal drug concentrations argues for development and evaluation of novel therapeutic strategies that will fully suppress viral replication in lymphatic tissues. These strategies could avert the long-term clinical consequences of chronic immune activation driven directly or indirectly by low-level viral replication to thereby improve immune reconstitution. [ABSTRACT FROM AUTHOR]

Highly active antiretroviral treatment has resulted in dramatically increased life expectancy among patients with HIV infection who are now aging while receiving treatment and are at risk of developing chronic diseases associated with advanced age. Similarities between aging and the courses of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome suggest that HIV infection compresses the aging process, perhaps accelerating comorbidities and frailty. In a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the HIV Medical Association, the National Institute on Aging, and the National Institute on Allergy and Infectious Diseases, researchers in infectious diseases, geriatrics, immunology, and gerontology met to review what is known about HIV infection and aging, to identify research gaps, and to suggest high priority topics for future research. Answers to the questions posed are likely to help prioritize and balance strategies to slow the progression of HIV infection, to address comorbidities and drug toxicity, and to enhance understanding about both HIV infection and aging. [ABSTRACT FROM AUTHOR]

Durable and sustained suppression of HIV replication can be achieved as demonstrated in several recent clinical trials of antiretroviral (ARV) regimens. However, the efficacy demonstrated in the experimental setting does not always translate to effectiveness in the clinical setting. The frequency and number of medications (conventionally referred to as the pill count) contribute to regimen effectiveness. However, clinicians and HIV-infected patients recognise that there are several other characteristics of an ARV regimen that are equally important contributors to its effectiveness. Potency and durability, the potential for drugdrug interactions, and the occurrence of adverse events also contribute to the effectiveness and complexity of a drug regimen. A comprehensive consideration of factors associated with efficacy will optimise the translation to effectiveness for the individual infected with HIV. [ABSTRACT FROM AUTHOR]

The article focuses on the analysis of CYP2B6-G516T polymorphisms in HIV-infected children who are receiving highly active antiretroviral therapy containing efavirenz (EFV). The impact of CYP2B6-G516T polymorphisms on EFV concentrations may be different in children because of differences in liver maturation and drug dosage.

Studies measures of antiretroviral medication adherence and virologic response in AIDS in clinical trials by researchers from the U.S. Use of antiretroviral regimen adherence as a critical determinant of virologic success; Indications from HIV-infection studies showing that a very high degree of adherence is necessary for optimal suppression of HIV RNA levels in plasma; Association of poor adherence with virologic failure and the emergence of drug-resistant strains of HIV.

AIDS Clinical Trials Group study 359 was a controlled study of saquinavir with either ritonavir or nelfinavir, together with delavirdine, adefovir, or both, in indinavir-experienced persons. Saquinavir was common in all study arms, and the study investigated relationships among characteristics of patients, saquinavir area under the curve (AUC) and trough concentrations (Cmin), and virologic response. Concentrations of saquinavir were higher when it was combined with ritonavir than when it was combined with nelfinavir and were lower with adefovir-containing regimens. Females had higher AUC and Cmin values than did males. Higher saquinavir AUC and Cmin values were associated with a greater likelihood of human immunodeficiency virus (HIV) RNA levels ≤500 copies/mL (P = .008) and were better predictors of response than was the saquinavir inhibitory quotient. Males had a lower probability of having HIV RNA levels ≤500 copies/mL at week 16 than did females (28% vs. 42%; adjusted odds ratio, 0.43). In this study, a greater proportion of females had HIV RNA levels ≤500 copies/mL than did males, which can be attributed to higher concentrations of saquinavir in females than in males. [ABSTRACT FROM AUTHOR]

Study Objective. To evaluate and describe the parameters and characteristics of different drug regimens in children infected with human immunodeficiency virus (HIV). Design. Randomized, open-label, multicenter study. Setting. Pediatric HIV research clinics in the United States and Puerto Rico. Patients. Twenty-one H1V-infected children, aged 3-14 years, who were clinically stable and treated with the same antiretroviral therapy for 16 weeks or longer. Intervention. In step 1, children were randomized to receive one of three treatment regimens: zidovudine plus lamivudine, ritonavir plus zidovudine and lamivudine, or ritonavir plus stavudine. Patients originally assigned to the zidovudine plus lamivudine group in step 1 were eligible to progress to step 2 if their HIV RNA values at week 12, 24, or 36 were 10,000 copies/ml or greater but 100,000 copies/ml or less. In step 2 they received a regimen of ritonavir plus stavudine and nevirapine. Measurements and Main Results. Seven children were randomized to each of the three treatment regimens. Concentrations of the agents were quantitated at steady state after observed doses, and the pharmacokinetic parameters were determined. Nevirapine concentrations were not determined. One child was excluded from analysis because pharmacokinetic parameters could not be estimated. Ritonavir oral clearance was slower in the pooled cohort of children who received stavudine compared with zidovudine and lamivudine. Stavudine oral clearance was marginally faster when combined with ritonavir and nevirapine compared with only ritonavir. Conclusion. Therapy for HIV is complex, and pharmacodynamic data indicate that relationships exist between systemic concentrations of antiretroviral drugs and virologic response. Careful drug interaction studies have not been conducted for all treatment regimens, and it will not be surprising if unexpected interactions are found. Pharmacokinetic studies to address... [ABSTRACT FROM AUTHOR]

Assesses the clinical, immunologic and virologic effects and the pharmacokinetics of human immunodeficiency virus (HIV) human hyperimmune immunoglobulin (HIVIG) in HIV-infected children aged 2-11 years. Efficacy of the use of antibody in the treatment of viral infection; HIVIG p24 antibody concentrations at baseline and average peak and trough levels.

Determines the pharmacokinetic properties, tolerance, safety and antiviral activity of combination therapy with stavudine and didanosine in children with advanced human immunodeficiency virus infection. Baseline patient characteristics; Clinical observations; Immunologic and virologic observations.

The author reflects on the article "Pharmacokinetics and pharmacodynamics of antiretrovirals in the central nervous system" by A. Calcagno and colleagues. Topics discussed include aim of the study to predict potency of cerebrospinal fluid (CSF) concentrations of antiretroviral drugs, highest CSF concentration in darunavir/ritonavir and lowest in atazanavir, and comparison of randomized study of a central nervous system (CNS) penetration effectiveness (CPE)-based CNS-targeted regimen.

Background We evaluated the fully human polyclonal antibody product SAB-185 in a phase 3 trial for COVID-19. Methods Nonhospitalized high-risk adults within 7 days of symptom onset were randomized 1:1 to open-label SAB-185 3840 units/kg or casirivimab/imdevimab 1200 mg. Noninferiority comparison was undertaken for pre-Omicron population (casirivimab/imdevimab expected to be fully active) and superiority comparison for the Omicron population (casirivimab/imdevimab not expected to be active). Primary outcomes were the composite of all-cause hospitalizations/deaths and grade ≥3 treatment-emergent adverse events (TEAEs) through day 28. A secondary outcome was time to sustained symptom resolution. Results Enrollment ended early due to low hospitalization/death rates upon Omicron emergence; 255 adults were in pre-Omicron and 392 in Omicron populations. Hospitalizations/deaths occurred in 6 (5.0%) and 3 (2.2%) of pre-Omicron SAB-185 and casirivimab/imdevimab arms (absolute difference 2.7%; 95% confidence interval [CI], −2.3%-8.6%); and 5 (2.5%) versus 3 (1.5%) (absolute difference 1.0%; 95% CI, −2.3%-4.5%) for Omicron. All risk ratios for grade ≥3 TEAEs were not significant. Time to symptom resolution was significantly shorter for SAB-185 for Omicron only: 18 versus >25 days; P =.006. Conclusions SAB-185 had an acceptable safety profile with faster symptom resolution in the Omicron population. Clinical Trials Registration NCT04518410. [ABSTRACT FROM AUTHOR]

Background Bemnifosbuvir (AT-527) is a novel oral guanosine nucleotide antiviral drug for the treatment of persons with COVID-19. Direct assessment of drug disposition in the lungs, via bronchoalveolar lavage, is necessary to ensure antiviral drug levels at the primary site of SARS-CoV-2 infection are achieved. Objectives This Phase 1 study in healthy subjects aimed to assess the bronchopulmonary pharmacokinetics, safety and tolerability of repeated doses of bemnifosbuvir. Methods A total of 24 subjects were assigned to receive bemnifosbuvir twice daily at doses of 275, 550 or 825 mg for up to 3.5 days. Results AT-511, the free base of bemnifosbuvir, was largely eliminated from the plasma within 6 h post dose in all dosing groups. Antiviral drug levels of bemnifosbuvir were consistently achieved in the lungs with bemnifosbuvir 550 mg twice daily. The mean level of the guanosine nucleoside metabolite AT-273, the surrogate of the active triphosphate metabolite of the drug, measured in the epithelial lining fluid of the lungs was 0.62 µM at 4–5 h post dose. This exceeded the target in vitro 90% effective concentration (EC90) of 0.5 µM for antiviral drug exposure against SARS-CoV-2 replication in human airway epithelial cells. Bemnifosbuvir was well tolerated across all doses tested, and most treatment-emergent adverse events reported were mild in severity and resolved. Conclusions The favourable pharmacokinetics and safety profile of bemnifosbuvir demonstrates its potential as an oral antiviral treatment for COVID-19, with 550 mg bemnifosbuvir twice daily currently under further clinical evaluation in persons with COVID-19. [ABSTRACT FROM AUTHOR]

Background Protease inhibitor-based antiretroviral therapy may be used in resource-limited settings in persons with human immunodeficiency virus and tuberculosis (HIV-TB). Data on safety, pharmacokinetics/pharmacodynamics (PK/PD), and HIV-TB outcomes for lopinavir/ritonavir (LPV/r) used with rifampin (RIF) or rifabutin (RBT) are limited. Methods We randomized adults with HIV-TB from July 2013 to February 2016 to arm A, LPV/r 400 mg/100 mg twice daily + RBT 150 mg/day; arm B, LPV/r 800 mg/200 mg twice daily + RIF 600 mg/day; or arm C, LPV/r 400 mg/100 mg twice daily + raltegravir (RAL) 400 mg twice daily + RBT 150 mg/day. All received two nucleoside reverse transcriptase inhibitors and other TB drugs. PK visits occurred on day 12 ± 2. Within-arm HIV-TB outcomes were summarized using proportions and 95% CIs; PK were compared using Wilcoxon tests. Results Among 71 participants, 52% were women; 72% Black; 46% Hispanic; median age, 37 years; median CD4+ count, 130 cells/mm3; median HIV-1 RNA, 4.6 log10 copies/mL; 46% had confirmed TB. LPV concentrations were similar across arms. Pooled LPV AUC12 (157 203 hours × ng/mL) and Ctrough (9876 ng/mL) were similar to historical controls; RBT AUC24 (7374 hours × ng/mL) and Ctrough (208 ng/mL) were higher, although 3 participants in arm C had RBT Cmax <250 ng/mL. Proportions with week 48 HIV-1 RNA <400 copies/mL were 58%, 67%, and 61%, respectively, in arms A, B, and C. Conclusions Double-dose LPV/r+RIF and LPV/r+RBT 150mg/day had acceptable safety, PK and TB outcomes; HIV suppression was suboptimal but unrelated to PK. Faster RBT clearance and low Cmax in 3 participants on RBT+RAL requires further study. [ABSTRACT FROM AUTHOR]

Three years after SARS-CoV-2 emerged as a global infectious threat, the virus has become endemic. The neurological complications such as depression, anxiety, and other CNS complications after COVID-19 disease are increasing. The brain, and CSF have been shown as viral reservoirs for SARS-CoV-2, yielding a potential hypothesis for CNS effects. Thus, we investigated the CNS pharmacology of orally dosed nirmatrelvir/ritonavir (NMR/RTV). Using both an in vitro and an in vivo rodent model, we investigated CNS penetration and potential pharmacodynamic activity of NMR. Through pharmacokinetic modeling, we estimated the median CSF penetration of NMR to be low at 18.11% of plasma with very low accumulation in rodent brain tissue. Based on the multiples of the 90% maximal effective concentration (EC90) for SARS-CoV-2, NMR concentrations in the CSF and brain do not achieve an exposure level similar to that of plasma. A median of only 16% of all the predicted CSF concentrations in rats were > 3xEC90 (unadjusted for protein binding). This may have implications for viral persistence and neurologic post-acute sequelae of COVID-19 if increased NMR penetration in the CNS leads to decreased CNS viral loads and decreased CNS inflammation. [ABSTRACT FROM AUTHOR]

Discusses studies of the safety and efficacy of the HIV drug enfuvirtide. Interactions between viral envelope glycoproteins and host receptors which cause HIV fusion and entry into target cells; Description of enfuvirtide, which is a synthetic 36-aminoacid peptidomimetic which binds to a region of gp41 and prevents the conformational change necessary for fusion of HIV to the CD4+cell; Observation that the addition of enfuvirtide to an optimized regimen of antiretroviral agents has been shown to improve virological and immunological responses in patients who are highly experienced with previous treatment.

Background: Pediatric brain tumors (PBT) stand as the leading cause of cancer‐related deaths in children. Chemoradiation protocols have improved survival rates, even for non‐resectable tumors. Nonetheless, radiation therapy carries the risk of numerous adverse effects that can have long‐lasting, detrimental effects on the quality of life for survivors. The pursuit of chemotherapeutics that could obviate the need for radiotherapy remains ongoing. Several anti‐tumor agents, including sunitinib, valproic acid, carboplatin, and panobinostat, have shown effectiveness in various malignancies but have not proven effective in treating PBT. The presence of the blood–brain barrier (BBB) plays a pivotal role in maintaining suboptimal concentrations of anti‐cancer drugs in the central nervous system (CNS). Ongoing research aims to modulate the integrity of the BBB to attain clinically effective drug concentrations in the CNS. However, current findings on the interaction of exogenous chemical agents with the BBB remain limited and do not provide a comprehensive explanation for the ineffectiveness of established anti‐cancer drugs in PBT. Methods: We conducted our search for chemotherapeutic agents associated with the blood–brain barrier (BBB) using the following keywords: Chemotherapy in Cancer, Chemotherapy in Brain Cancer, Chemotherapy in PBT, BBB Inhibition of Drugs into CNS, Suboptimal Concentration of CNS Drugs, PBT Drugs and BBB, and Potential PBT Drugs. We reviewed each relevant article before compiling the information in our manuscript. For the generation of figures, we utilized BioRender software. Focus: We focused our article search on chemical agents for PBT and subsequently investigated the role of the BBB in this context. Our search criteria included clinical trials, both randomized and non‐randomized studies, preclinical research, review articles, and research papers. Finding: Our research suggests that, despite the availability of potent chemotherapeutic agents for several types of cancer, the effectiveness of these chemical agents in treating PBT has not been comprehensively explored. Additionally, there is a scarcity of studies examining the role of the BBB in the suboptimal outcomes of PBT treatment, despite the effectiveness of these drugs for other types of tumors. [ABSTRACT FROM AUTHOR]

Sustainable HIV remission after antiretroviral therapy (ART) withdrawal, or post-treatment control (PTC), remains a top priority for HIV treatment. We observed surprising PTC in an MHC-haplomatched cohort of MHC-M3+ SIVmac239+ Mauritian cynomolgus macaques (MCMs) initiated on ART at two weeks post-infection (wpi). None of the MCMs possessed MHC haplotypes previously associated with SIV control. For six months after ART withdrawal, we observed undetectable or transient viremia in seven of the eight MCMs, despite detecting replication competent SIV using quantitative viral outgrowth assays. In vivo depletion of CD8α+ cells induced rebound in all animals, indicating the observed PTC was mediated, at least in part, by CD8α+ cells. With intact proviral DNA assays, we found that MCMs had significantly smaller viral reservoirs two wpi than a cohort of identically infected rhesus macaques, a population that rarely develops PTC. We found a similarly small viral reservoir among six additional SIV+ MCMs in which ART was initiated at eight wpi, some of whom exhibited viral rebound. These results suggest that an unusually small viral reservoir is a hallmark among SIV+ MCMs. By evaluating immunological differences between MCMs that did and did not rebound, we identified that PTC was associated with a reduced frequency of CD4+ and CD8+ lymphocyte subsets expressing exhaustion markers. Together, these results suggest a combination of small reservoirs and immune-mediated virus suppression contribute to PTC in MCMs. Further, defining the immunologic mechanisms that engender PTC in this model may identify therapeutic targets for inducing durable HIV remission in humans. Author summary: The ultimate goal of human immunodeficiency virus (HIV) therapeutic development is to enable HIV+ individuals to stop taking daily lifelong antiretroviral therapeutics (ART) and remain in virological remission, an outcome called post-treatment control. Post-treatment control is challenging to study because it is very rare in humans. Thus, there are currently no therapeutics that lead to post-treatment control. Simian immunodeficiency virus (SIV) in rhesus macaques is the most widely used preclinical model for HIV. However, post-treatment control is also uncommon in rhesus macaques. The mechanisms that govern post-treatment control remain largely unknown because PTC is so rare. Our lab observed surprising post-treatment control in a cohort of Mauritian cynomolgus macaques that were initiated on ART two weeks post-infection. While Mauritian cynomolgus macaques have been used for SIV research, they are not routinely used to study post-treatment control. We found that small viral reservoirs and immune-mediated virus suppression contribute to post-treatment control in Mauritian cynomolgus macaques. Moving forward, this model can be used to further define the mechanisms that engender post-treatment control as well as identify therapeutic targets in humans for inducing durable HIV remission. [ABSTRACT FROM AUTHOR]

Background SAB-185, a novel fully human IgG polyclonal immunoglobulin product, underwent phase 2 evaluation for nonhospitalized adults with mild-moderate coronavirus disease 2019 (COVID-19). Methods Participants received intravenous SAB-185 3840 units/kg (low-dose) or placebo, or 10 240 units/kg (high-dose) or placebo. Primary outcome measures were nasopharyngeal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA < lower limit of quantification (LLOQ) at study days 3, 7, and 14, time to symptomatic improvement, and safety through day 28. Results Two-hundred thirteen participants received low-dose SAB-185/placebo (n = 107/106) and 215 high-dose SAB-185/placebo (n = 110/105). The proportions with SARS-CoV-2 RNA < LLOQ were higher for SAB-185 versus placebo at days 3 and 7 and similar at day 14, and significantly higher at day 7 for high-dose SAB-185 versus placebo only, relative risk 1.23 (95% confidence interval, 1.01–1.49). At day 3, SARS-CoV-2 RNA levels were lower with low-dose and high-dose SAB-185 versus placebo: differences in medians of −0.78 log10 copies/mL (P =.08) and −0.71 log10 copies/mL (P =.10), respectively. No difference was observed in time to symptom improvement: median 11/10 days (P =.24) for low-dose SAB-185/placebo and 8/10 days (P =.50) for high-dose SAB-185/placebo. Grade ≥3 adverse events occurred in 5%/13% of low-dose SAB-185/placebo and 9%/12% of high-dose SAB-185/placebo. Conclusions SAB-185 was safe and generally well tolerated and demonstrated modest antiviral activity in predominantly low-risk nonhospitalized adults with COVID-19. Clinical Trials Registration.  NCT04518410. [ABSTRACT FROM AUTHOR]

Angiotensin Converting Enzyme 2 (ACE-2), Transmembrane Serine Protease 2 (TMPRSS-2) and Neuropilin-1 cellular receptors support the entry of SARS-CoV-2 into susceptible human target cells and are characterized at the molecular level. Some evidence on the expression of entry receptors at mRNA and protein levels in brain cells is available, but co-expression of these receptors and confirmatory evidence on brain cells is lacking. SARS-CoV-2 infects some brain cell types, but infection susceptibility, multiple entry receptor density, and infection kinetics are rarely reported in specific brain cell types. Highly sensitive Taqman ddPCR, flow-cytometry and immunocytochemistry assays were used to quantitate the expression of ACE-2, TMPRSS-2 and Neuropilin-1 at mRNA and protein levels on human brain-extracted pericytes and astrocytes, which are an integral part of the Blood-Brain-Barrier (BBB). Astrocytes showed moderate ACE-2 (15.9 ± 1.3%, Mean ± SD, n = 2) and TMPRSS-2 (17.6%) positive cells, and in contrast show high Neuropilin-1 (56.4 ± 39.8%, n = 4) protein expression. Whereas pericytes showed variable ACE-2 (23.1 ± 20.7%, n = 2), Neuropilin-1 (30.3 ± 7.5%, n = 4) protein expression and higher TMPRSS-2 mRNA (667.2 ± 232.3, n = 3) expression. Co-expression of multiple entry receptors on astrocytes and pericytes allows entry of SARS-CoV-2 and progression of infection. Astrocytes showed roughly four-fold more virus in culture supernatants than pericytes. SARS-CoV-2 cellular entry receptor expression and "in vitro" viral kinetics in astrocytes and pericytes may improve our understanding of viral infection "in vivo". In addition, this study may facilitate the development of novel strategies to counter the effects of SARS-CoV-2 and inhibit viral infection in brain tissues to prevent the spread and interference in neuronal functions. [ABSTRACT FROM AUTHOR]

Background: Pharmacokinetics (PK) and pharmacodynamics of efavirenz and its 8-hydroxy metabolite (8-OH-efavirenz) have not been robustly evaluated in older HIV-infected persons.Objectives: We investigated relationships between neuropsychological (NP) performance and efavirenz and 8-OH-efavirenz PK in HIV-infected individuals >50 years of age.Methods: A cross-sectional study of HIV-infected adults on an efavirenz-containing regimen. The 12 and 18 h post-dose plasma efavirenz and 8-OH-efavirenz were quantified. CYP2B6 polymorphisms were investigated. Participants underwent neuropsychological tests; surveys were used for depression, sleep quality and anxiety. We investigated potential correlations of efavirenz and 8-OH-efavirenz plasma concentrations with NP performance, sleep, depression, anxiety and CYP2B6 polymorphisms.Results: Thirty participants (24 men and 6 women) with mean age 57 years (range 50-68). Plasma efavirenz concentrations did not correlate with NP performance; however, higher plasma 8-OH-efavirenz correlated with better learning (P = 0.002), language (P = 0.002) and total NP z-scores (P = 0.003). No correlation was seen for efavirenz or 8-OH-efavirenz with sleep, anxiety or depression. Median 12 and 18 h efavirenz plasma concentrations were 1967 ng/mL (IQR 1476-2394) and 1676 ng/mL (IQR 1120-2062), respectively. Median 12 and 18 h 8-OH-efavirenz plasma concentrations were 378 ng/mL (IQR 223-589) and 384 ng/mL (IQR 216-621), respectively. CYP2B6 G516T was associated with significantly higher plasma efavirenz at 12 and 18 h (P = 0.02) but not worse NP function.Conclusions: Better neurocognitive functioning was associated with higher 8-OH-efavirenz but not efavirenz plasma concentrations. No correlation was observed with sleep or depression. These findings point to a need for greater understanding of the metabolic profile of efavirenz and 8-OH-efavirenz in plasma and the CNS and relationships with antiviral effect and neurotoxicity. [ABSTRACT FROM AUTHOR]

Background: Consistent long-term viral suppression has been difficult to achieve in children with human immunodeficiency virus type 1 (HIV-1) infection. We tested the safety and antiviral efficacy of a novel combination consisting of efavirenz, nelfinavir, and one or more nucleoside reverse-transcriptase inhibitors in 57 children previously treated with only nucleoside reverse-transcriptase inhibitors. Methods: The children were monitored for 48 weeks after the initiation of therapy. We assessed plasma concentrations of efavirenz and nelfinavir, plasma HIV-1 RNA levels, and lymphocyte subpopulations. Results: At base line, the 57 HIV-1–infected children (age range, 3.8 to 16.8 years) had a median of 699 CD4 cells per cubic millimeter and 10,000 copies of HIV-1 RNA per milliliter of plasma. The most common treatment-related effects of at least moderate severity were rash (in 30 percent of children), diarrhea (in 18 percent), neutropenia (in 12 percent), and biochemical abnormalities (in 12 percent). Serious side effects were uncommon. The mean values for the area under the curve for efavirenz and nelfinavir corresponded to expected values. In an intention-to-treat analysis, 76 percent of children had plasma HIV-1 RNA levels of less than 400 copies per milliliter after 48 weeks of therapy and 63 percent had levels of less than 50 copies per milliliter. A high plasma HIV-1 RNA level at base line significantly decreased the likelihood that plasma levels of HIV-1 RNA would become undetectable during treatment. Conclusions: In HIV-1–infected children who were previously treated with nucleoside reverse-transcriptase inhibitors, the combination of efavirenz, nelfinavir, and nucleoside reverse-transcriptase inhibitors was generally well tolerated and had a potent and sustained antiviral effect. (N Engl J Med 1999;341:1874-81.) [ABSTRACT FROM AUTHOR]

Background: Pharmacokinetic data are lacking for progestin-releasing subdermal contraceptive implants when used with either rilpivirine- or darunavir/ritonavir-based ART.Objectives: To characterize the pharmacokinetics of etonogestrel or levonorgestrel implants when administered with these ART regimens over 48 weeks.Patients and Methods: Two separate, parallel, three-group, non-randomized, pharmacokinetic studies evaluated either etonogestrel or levonorgestrel in women receiving rilpivirine- or darunavir-based ART compared with women without HIV (control group). Participants on ART were switched to rilpivirine-based ART with a run-in period of 6 weeks or darunavir-based ART with a run-in of 2 weeks prior to implant insertion. Plasma was collected on Day 0, and 1, 4, 12, 24, 36 and 48 weeks post-insertion. Plasma progestin concentrations were compared between ART and control groups by geometric mean ratio (GMR) and 90% CI.Results: At the primary endpoint of Week 24, progestin concentrations were similar between the rilpivirine and control groups [etonogestrel: 1.18 (0.99-1.37); levonorgestrel: 1.16 (0.97-1.33)]. At Week 24, progestin exposure was higher in the darunavir groups compared with the control group [etonogestrel: 2.56 (1.69-3.28); levonorgestrel: 1.89 (1.38-2.29)]. Results remained consistent through to Week 48. No differences in etonogestrel-related adverse events were observed, but both ART groups experienced more menstrual abnormalities versus the control group with levonorgestrel.Conclusions: Etonogestrel and levonorgestrel concentrations were not altered by rilpivirine-based ART. Although progestin concentrations were higher in the ART groups containing ritonavir-boosted darunavir, no implant-related serious adverse events were observed. Both progestin-releasing implants are an appropriate contraceptive option with either rilpivirine- or darunavir/ritonavir-based ART. [ABSTRACT FROM AUTHOR]

Abstract: An assay using ultrahigh pressure liquid chromatography and mass spectrometry detection was developed and validated for measurement of the HIV integrase inhibitor raltegravir (MK-0518) in human cell extracts. The assay is designed to utilize 200μl of 70% MeOH cell extract derived from human peripheral blood mononuclear cells or human tissue samples. The assay is linear over a range from 0.0023 to 9.2ngml−1. The average %CV (SD/Mean)*100 and %deviation ((observed−target)/target)*100 were less than 20% at the lower limit of quantification and less than 15% over the range of the curve. This assay is an accurate and highly sensitive method for determining raltegravir concentrations in cellular extracts with a lower limit 40 to over 100-fold lower than other methods in the literature. We also present a new processing method where a rapid spin through oil produced a significant increase in apparent intracellular raltegravir concentration compared with conventional processing. [Copyright &y& Elsevier]

Abstract: An LC/MS/MS assay for the determination of tenofovir (TNF) was developed and validated for use with the EDTA anticoagulated human plasma matrix. Heparin-treated plasma and serum matrices were also validated. After addition of adefovir as an internal standard, trifluoroacetic acid was used to produce a protein-free extract. Chromatographic separation was achieved with a Polar-RP Synergi, 2.0mm×150mm, reversed-phase analytical column. The mobile phase was 3% acetonitrile/1% acetic acid, aq. Detection of TNF and the internal standard was achieved by ESI MS/MS in the positive ion mode using 288/176 and 274/162 transitions, respectively. The method was linear from 10 to 750ng/ml with a minimum quantifiable limit of 10ng/ml when 250μl aliquots were analyzed. The usefulness of this LC/MS/MS method to routinely monitor plasma concentrations of TNF was demonstrated along with its ability to assist in the performance of pharmacokinetic studies. [Copyright &y& Elsevier]

Focuses on the treatment of HIV-infected adult patients with a single intravenous infusion of the recombinant antibody-like fusion protein PRO 54. Pharmacokinetic and immunogenicity analyses by enzyme-linked immunosorbent assay; Virologic analyses by reverse transcription-polymerase chain reaction; Decline in plasma HIV RNA.

Background: Multiple tissue reservoirs are established soon after HIV infection, and some tissues may also be pharmacological sanctuaries. Parenteral administration of antiretroviral (ARV) drugs for treatment and prevention of HIV infection is an active area of drug development. The influence of route of administration on ARV tissue pharmacokinetics is not known.Objectives: To investigate ARV pharmacokinetics in lymphatic and select non-lymphatic tissues (e.g. brain and testes) after intramuscular and subcutaneous administration compared with oral in BALB/c mice.Methods: Tissue concentrations of cobicistat, efavirenz, elvitegravir, maraviroc, rilpivirine, tenofovir alafenamide and tenofovir disoproxil fumarate were determined. The tissue penetration ratio (TPR) was the primary measure for comparison; a change in TPR arises from factors affecting tissue distribution controlling for changes in systemic bioavailability.Results: Intramuscular and subcutaneous delivery increased TPRs in the lymph node and spleen for 27 of 28 (96%) drug administration events. Decreased TPRs, however, were found in some tissues such as the brain and testes.Conclusions: These results demonstrate a change in route of drug administration from oral to intramuscular or subcutaneous can change tissue uptake. This has implications for HIV pharmacotherapy. For example, HIV persists in lymphoid tissues despite long-term oral ARV therapy, and low ARV concentrations have been found in lymphoid tissues. The improved ARV lymphatic tissue bioavailability with intramuscular and subcutaneous administration allows future studies to investigate these routes of drug administration as a therapeutic manoeuvre to limit viral persistence and eliminate viral sanctuaries in the lymphatic tissues, which is a prerequisite for eradication of HIV. [ABSTRACT FROM AUTHOR]

Membrane-associated drug transport proteins and drug metabolic enzymes could regulate intracellular antiretroviral (ARV) drug concentrations in HIV-1 target cells such as myeloid cells. We investigated the expression of these transporters and enzymes in monocyte subsets and monocyte-derived macrophages (MDMs) isolated from peripheral blood mononuclear cells (PBMCs) of HIV-uninfected individuals (HIV-negative) and people living with HIV receiving viral suppressive antiretroviral therapy (ART; HIV+ ART) and examined plasma and intracellular ARV concentrations. Monocytes were isolated from PBMCs of 12 HIV-negative and 12 HIV+ART donors and differentiated into MDMs. The mRNA and protein expression of drug transporters and metabolic enzymes were analyzed by quantitative real-time polymerase chain reaction and flow cytometry, respectively. ARV drug concentrations were quantified in plasma, PBMCs, monocytes, and MDMs by LCMS/MS. The mRNA expression of relevant ARV transporters or metabolic enzymes, ABCB1/P-gp, ABCG2/BCRP, ABCC1/MRP1, ABCC4/MRP4, SLC22A1/OCT1, SLC29A2/ENT2, CYP2B6, CYP2D6, and UGT1A1, was demonstrated in monocytes and MDMs of 2 to 4 HIV-negative donors. P-gp, BCRP, and MRP1 proteins were differentially expressed in classical, intermediate, and nonclassical monocytes and MDMs of both HIV+ART and HIVnegative donors. Intracellular concentrations of ARVs known to be substrates of these transporters and metabolic enzymes were detected in monocytes of HIV+ART donors but were undetectable in MDMs. In this study, we demonstrated the expression of drug transporters and metabolic enzymes in monocytes and MDMs of HIV-negative and HIV+ART individuals, which could potentially limit intracellular concentrations of ARVs and contribute to residual HIV replication. Further work is needed to assess the role of these transporters in the penetration of ARVs in tissue macrophages. [ABSTRACT FROM AUTHOR]

The NIH Virtual SARS-CoV-2 Antiviral Summit, held on 6 November 2020, was organized to provide an overview on the status and challenges in developing antiviral therapeutics for coronavirus disease 2019 (COVID-19), including combinations of antivirals. Scientific experts from the public and private sectors convened virtually during a live videocast to discuss severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets for drug discovery as well as the preclinical tools needed to develop and evaluate effective small-molecule antivirals. The goals of the Summit were to review the current state of the science, identify unmet research needs, share insights and lessons learned from treating other infectious diseases, identify opportunities for public-private partnerships, and assist the research community in designing and developing antiviral therapeutics. This report includes an overview of therapeutic approaches, individual panel summaries, and a summary of the discussions and perspectives on the challenges ahead for antiviral development. [ABSTRACT FROM AUTHOR]

An international HIV pharmacology specialty laboratory (PSL) was established at the University of Zimbabwe to increase bioanalytical and investigator capacities. Quantitation of plasma nevirapine in samples from the AIDS Clinical Trials Group protocol 5279 was compared between the University of Nebraska Medical Center PSL and the University of Zimbabwe PSL. Both PSLs employed internally developed methods utilising reverse-phase high-performance liquid chromatography with ultraviolet detection. Eighty-seven percent of the cross-validation results exhibited ± 20% difference. [ABSTRACT FROM AUTHOR]

The newest class of antiretrovirals for all persons living with HIV are the integrase strand transfer inhibitors (INSTIs). Since 2007, five INSTIs have been introduced: raltegravir, elvitegravir, dolutegravir, bictegravir, and cabotegravir. The INSTIs have favorable pharmacokinetic and pharmacodynamic properties, which contribute to both their effectiveness and their ease of use. With the exception of cabotegravir, each INSTI is US Food and Drug Administration approved for treatment-naïve individuals initiating antiretroviral therapy. All of the INSTIs, except raltegravir, are approved for antiretroviral treatment simplification for virologically suppressed patients without INSTI resistance. Data also support the use of dolutegravir and raltegravir in individuals with antiretroviral resistance as part of an optimized antiretroviral regimen. INSTIs are generally well tolerated by people living with HIV compared with older classes of antiretrovirals, but emerging data suggest that some INSTIs contribute to weight gain. Due to their efficacy, safety, and ease of use, HIV treatment guidelines recommend oral INSTIs as preferred components of antiretroviral therapy for individuals initiating therapy. The newest INSTI, cabotegravir, represents an alternative to oral administration of life-long antiretroviral therapy with the availability of a long-acting injectable formulation. This review summarizes the current use of INSTIs in adults living with HIV, highlighting the similarities and differences within the class related to pharmacodynamics, pharmacokinetics, safety, dosing, and administration that contribute to their role in modern antiretroviral therapy. [ABSTRACT FROM AUTHOR]

Dyskinesia induced by long‐term L‐Dopa (LID) therapy in Parkinson disease is associated with altered striatal function whose molecular bases remain unclear. Here, a transcriptomic approach was applied for comprehensive analysis of distinctively regulated genes in striatal tissue, their specific pathways, and functional‐ and disease‐associated networks in a rodent model of LID. This approach has identified transforming growth factor beta type 1 (TGFβ1) as a highly upregulated gene in dyskinetic animals. TGFβ1 pathway is a top aberrantly regulated pathway in the striatum following LID development based on differentially expressed genes (> 1.5 fold change and P < 0.05). The induction of TGFβ1 pathway specific genes, TGFβ1, INHBA, AMHR2 and PMEPA1 was also associated with regulation of NPTX2, PDP1, SCG2, SYNPR, TAC1, TH, TNNT1 genes. Transcriptional network and upstream regulator analyses have identified AKT‐centered functional and ERK‐centered disease networks revealing the association of TGFβ1, IL‐1β and TNFα with LID development. Therefore, results support that TGFβ1 pathway is a major contributor to the pathogenic mechanisms of LID. [ABSTRACT FROM AUTHOR]

Occasional zoonotic viral attacks on immunologically naive populations result in massive death tolls that are capable of threatening human survival. Currently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the infectious agent that causes coronavirus disease (COVID-19), has spread from its epicenter in Wuhan China to all parts of the globe. Real-time mapping of new infections across the globe has revealed that variable transmission patterns and pathogenicity are associated with differences in SARS-CoV-2 lineages, clades, and strains. Thus, we reviewed how changes in the SARS-CoV-2 genome and its structural architecture affect viral replication, immune evasion, and transmission within different human populations. We also looked at which immune dominant regions of SARS-CoV-2 and other coronaviruses are recognized by Major Histocompatibility Complex (MHC)/Human Leukocyte Antigens (HLA) genes and how this could impact on subsequent disease pathogenesis. Efforts were also placed on understanding immunological changes that occur when exposed individuals either remain asymptomatic or fail to control the virus and later develop systemic complications. Published autopsy studies that reveal alterations in the lung immune microenvironment, morphological, and pathological changes are also explored within the context of the review. Understanding the true correlates of protection and determining how constant virus evolution impacts on host-pathogen interactions could help identify which populations are at high risk and later inform future vaccine and therapeutic interventions. [ABSTRACT FROM AUTHOR]

Antiretroviral therapy in people living with HIV can achieve potent, long-term suppression of HIV plasma viremia and has increased life expectancy. The central nervous system is infected early after virus acquisition and remains a reservoir for HIV. HIV-associated neurocognitive disorders (HAND) are an end-organ manifestation of HIV infection. The need to address neurological complications caused by HAND is significant as approximately 50% of people living with HIV on suppressive antiretroviral therapy are estimated to have some form of HAND. This review discusses the pathophysiology of HAND, CSF/CNS penetration and clinical pharmacology of antiretrovirals including pharmacokinetic/pharmacodynamic relationships, the persistence of HIV in the brain, and future therapeutic approaches to preserve and improve sustained viral suppression in the brain. [ABSTRACT FROM AUTHOR]

Bictegravir, cabotegravir, dolutegravir, elvitegravir, and raltegravir are members of the latest class of antiretrovirals available to treat human immunodeficiency virus (HIV) infection, the integrase strand transfer inhibitors. Integrase strand transfer inhibitors are potent inhibitors of the HIV integrase enzyme with IC90/95 values in the low nanogram per milliliter range and they retain antiviral activity against strains of HIV with acquired resistance to other classes of antiretrovirals. Each of the integrase strand transfer inhibitors have unique pharmacokinetic/pharmacodynamic properties, influencing their role in clinical use in specific subsets of patients. Cabotegravir, approved for use in Canada but not yet by the US Food and Drug Administration, is formulated in both oral and intramuscular formulations; the latter of which has shown efficacy as a long-acting extended-release formulation. Cabotegravir, raltegravir, and dolutegravir have minimal drug–drug interaction profiles, as their metabolism has minimal cytochrome P450 involvement. Conversely, elvitegravir metabolism occurs primarily via cytochrome P450 3A4 and requires pharmacokinetic boosting to achieve systemic exposures amenable to once-daily dosing. Bictegravir metabolism has similar contributions from both cytochrome P450 3A4 and uridine 5ʹ-diphospho-glucuronosyltransferase 1A1. Bictegravir, dolutegravir, and raltegravir are recommended components of initial regimens for most people with HIV in the US adult and adolescent HIV treatment guidelines. This review summarizes and compares the pharmacokinetics and pharmacodynamics of the integrase strand transfer inhibitor agents, and describes specific pharmacokinetic considerations for persons with hepatic impairment, renal dysfunction, pregnancy, and co-infections. [ABSTRACT FROM AUTHOR]

Current strategies to treat tuberculosis (TB) and co-morbidities involve multidrug combination therapies. Rifamycin antibiotics are a key component of TB therapy and a common source of drug–drug interactions (DDIs) due to induction of drug metabolizing enzymes (DMEs). Management of rifamycin DDIs are complex, particularly in patients with co-morbidities, and differences in DDI potential between rifamycin antibiotics are not well established. DME profiles induced in response to tuberculosis antibiotics (rifampin, rifabutin and rifapentine) were compared in primary human hepatocytes. We identified rifamycin induced DMEs, cytochrome P450 (CYP) 2C8/3A4/3A5, SULT2A, and UGT1A4/1A5 and predicted lower DDIs of rifapentine with 58 clinical drugs used to treat co-morbidities in TB patients. Transcriptional networks and upstream regulator analyses showed FOXA3, HNF4α, NR1I2, NR1I3, NR3C1 and RXRα as key transcriptional regulators of rifamycin induced DMEs. Our study findings are an important resource to design effective medication regimens to treat common co-conditions in TB patients. [ABSTRACT FROM AUTHOR]

Background: Sex differences in studies of antiretroviral (ART) drug exposure and treatment outcomes support the hypothesis that some ART combinations may not be well tolerated in women. We evaluated disparities in outcomes between men and women participating in ACTG A5288, an interventional strategy trial for individuals failing a protease inhibitor--based second-line ART regimen in low- and middle-income countries. Methods: Participants were assigned to one of 4 cohorts (A-D) based on resistance profiles and ART history. Cohort A had no lopinavir/ritonavir (LPV/r) resistance and stayed on their second-line regimen, and cohorts B, C, and D had increasing resistance and accessed novel ART regimens. In this secondary analysis, we evaluated sex differences in the primary endpoint, HIV-1 RNA ≤200 copies/mL at week 48; confirmed virologic failure ≥1000 copies/mL (VF); and clinical outcomes and adverse events (intent-totreat). Results: Women made up 258/545 (47%) of the study population. More women than men were assigned to cohort A. Median follow-up was 72 weeks. Fewer women than men had HIV-1 RNA ≤200 copies/mL at week 48: 39% vs. 49% in cohort A and 83% vs. 89% in cohorts B, C, and D combined. More women experienced VF, grade ≥3 signs and symptoms, but similar grade ≥3 diagnoses or laboratory abnormalities. Conclusions: More women than men entered the study with a resistance profile suggesting that their second-line regimen could have been effective in maintaining virologic suppression. The more frequent occurrence of grade ≥3 signs and symptoms in women suggests that tolerability issues were under recognized in women on protease inhibitor--based therapy. [ABSTRACT FROM AUTHOR]

Background: Transwomen have an increased risk of HIV acquisition compared with other adults. Drug-drug interactions between pre-exposure prophylaxis (PrEP) and gender-affirming therapy are cited as a reason for poor PrEP uptake among transwomen. We evaluated plasma tenofovir and emtricitabine pharmacokinetics and their active intracellular anabolites, tenofovir-diphosphate and emtricitabine-triphosphate, in transwomen receiving feminizing hormones.Methods: We enrolled HIV-negative transwomen (≥19 years) not receiving PrEP. Participants took oral tenofovir disoproxil fumarate/emtricitabine 300/200 mg daily for 14 days. Plasma was collected at 0 h (pre-dose), 0.5, 1, 2, 3, 4, 6, 8 and 12 h on day 14 post-tenofovir disoproxil fumarate/emtricitabine dose. The plasma AUC0-24 was calculated using the trapezoidal rule and compared with historical HIV-negative cisgender adults as geometric mean ratios (GMRs, 90% CI). Secondarily, tenofovir-diphosphate and emtricitabine-triphosphate from PBMCs collected at 0 h and 12 h were reported descriptively as geometric means (90% CI). Clinical trials registration: NCT03270969.Results: Among 15 transwomen (mean age 32 years), geometric mean tenofovir and emtricitabine plasma AUC0-24 were lower compared with controls: tenofovir, 2.10 versus 2.76 mg·h/L, GMR 0.76 (0.65-0.90), P = 0.01; emtricitabine, 9.15 versus 10.64 mg·h/L, GMR 0.86 (0.75-0.98), P = 0.07. Tenofovir-diphosphate and emtricitabine-triphosphate concentrations were higher than previously reported in the literature: 167.1 (146.6-190.5) fmol/106 cells and 15.4 (13.8-17.3) pmol/106 cells, respectively.Conclusions: We observed lower plasma tenofovir and emtricitabine concentrations in transwomen compared with historical cisgender adults, yet intracellular tenofovir-diphosphate and emtricitabine-triphosphate concentrations were higher than previously reported in PBMCs. Understanding the differences of PrEP pharmacokinetics in plasma and tissue compartments and the resultant impact on efficacy remains important for transwomen. [ABSTRACT FROM AUTHOR]

Etravirine is a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) for the treatment of human immunodeficiency virus type 1 infection. It is a potent inhibitor of HIV reverse transcriptase and retains activity against wild-type and most NNRTI-resistant HIV. The pharmacokinetic profile of etravirine and clinical data support twice-daily dosing, although once-daily dosing has been investigated in treatment-naïve and treatment-experienced persons. Despite similar pharmacokinetic and pharmacodynamic results compared with twice-daily dosing, larger studies are needed to fully support once-daily etravirine dosing in treatment-naïve individuals. Etravirine is reserved for use in third- or fourth-line antiretroviral treatment regimens, as recommended, for example, in treatment guidelines by the US Department of Health and Human Services-Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents Living with HIV. Etravirine exhibits the potential for bi-directional drug-drug interactions with other antiretrovirals and concomitant medications through its interactions with cytochrome P450 (CYP) isozymes: CYP3A4, CYP2C9, and CYP2C19. This review summarizes the pharmacokinetic and pharmacodynamic parameters of etravirine, with particular attention to information on drug-drug interactions and use in special patient populations, including children/adolescents, women, persons with organ dysfunction, and during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Extracellular vesicles (EVs) are cell-derived vesicles with diverse functions in intercellular communication including disease and infection, and EVs seem to influence HIV-1 pathogenesis. EVs isolated from HIV-1--uninfected semen (SE), but not blood (BE), contain factors that interfere with HIV-1 infection and replication in target cells. The reason for this dichotomy is unknown. Furthermore, the effect of HIV-1 infection and antiretroviral (ARV) drugs on the anti--HIV-1 effects of SE and BE is unknown. Here, we characterize EVs and EV-free plasma isolated from HIV-infected donor semen and blood and their effects on HIV infection. Methods: EVs and EV-free plasma were purified from autologous blood and semen of HIV-negative, HIV-infected antiretroviral therapy (ART)-naïve, and HIV-infected ART-treated participants. HIV infection was assessed in a TZM-bl cell reporter system. ARV concentrations were analyzed using liquid chromatography-mass spectrometry. Results: SE isolated from both HIV-negative and HIV-infected, ART-naïve donors inhibited HIV-1 infection, but BE and semen and blood EV-free plasma did not. By contrast, BE, SE, and EV-free plasma from HIV-infected, ART-treated donors inhibited HIV-1. Importantly, exosomes isolated from ART-treated donors contained concentrations of ARV drugs (ART-EVs) at biologically relevant inhibitory levels. Conclusions: The HIV-1--inhibitory phenotype of SE is independent of donor HIV-1 or ART status, and ARV drugs and their metabolites are SE- and BE-associated in vivo. [ABSTRACT FROM AUTHOR]

Adherence with antiretroviral therapy is important for preventing disease progression and HIV transmission. The co‐encapsulated pill sensor system sends a signal through a cutaneous patch and allows real‐time monitoring of pill ingestion. A 16‐week pilot study used a sensor system in 15 HIV‐infected individuals with real‐time monitoring of pill‐taking with a personalized short message system text. System acceptability was assessed by survey at weeks 4, 8, 12, and 16. Follow‐up occurred in 80% of subjects through 8 weeks. The system effectively collected measures of pill ingestion, which triggered text message reminders. Only 2 of 14 participants stated that co‐encapsulated pills were "unable to take" or "poorly tolerated." At least 75% of respondents stated at each visit that the patch was very or somewhat comfortable. With regard to text message reminders, only 10–15% of the participants at any visit did not find the messages to be helpful. Larger studies will define the utility of this system to assess antiretroviral adherence relative to standard measures. [ABSTRACT FROM AUTHOR]

Background: The secondary lymphoid tissues (LTs), lymph nodes (LNs) and gut-associated lymphoid tissue (GALT) are considered reservoirs for HIV. Antiretrovirals (ARVs) have lower penetration into LT. In vitro models predictive of ARV LT penetration have not been established.Objectives: To develop an in vitro model of LT bioavailability using human lymphoid endothelial cells (HLECs) and investigate its predictability with in vivo pharmacokinetic (PK) studies in mice.Methods: ARV bioavailability in HLECs was evaluated at the maximum plasma concentration (Cmax) observed in HIV-infected patients. ARVs were: abacavir, atazanavir, darunavir, dolutegravir, efavirenz, elvitegravir, emtricitabine, maraviroc, raltegravir, rilpivirine, ritonavir, tenofovir disoproxil fumarate and the PK booster cobicistat. The LT PK of representative drugs showing high (efavirenz), intermediate (dolutegravir) and low (emtricitabine) HLEC bioavailability was investigated in BALB/c mice given 50/10/30 mg/kg efavirenz/dolutegravir/emtricitabine orally, daily for 3 days. The concordance of in vitro and in vivo ARV bioavailability was examined.Results: ARVs showed high (>67th percentile; rilpivirine, efavirenz, elvitegravir and cobicistat), intermediate (67th-33rd percentile; ritonavir, tenofovir disoproxil fumarate, dolutegravir and maraviroc) and low (<33rd percentile; atazanavir, darunavir, raltegravir, emtricitabine and abacavir) HLEC bioavailability. The hierarchy of efavirenz, dolutegravir and emtricitabine bioavailability in LN, gut and brain tissues of mice was: efavirenz>dolutegravir>emtricitabine.Conclusions: ARVs displayed distinct HLEC penetration patterns. PK studies of representative ARVs in LT of mice were concordant with HLEC bioavailability. These findings support further development of this approach and its translational predictability in humans. [ABSTRACT FROM AUTHOR]

Data on the relationship of antiretroviral exposure to measures of human immunodeficiency virus (HIV) persistence are limited. To address this gap, multiple viral, immunologic, and pharmacologic measures were analyzed from individuals with sustained virologic suppression on therapy (median 7 years) in the AIDS Clinical Trials Group A5321 cohort. Among 110 participants on tenofovir-(TFV)-disoproxil-fumarate (TDF)/emtricitabine (FTC)-containing regimens, we found no significant correlation between hair concentrations of individual antiretrovirals (ARVs) in the regimen and measures of HIV persistence (plasma HIV-1 RNA by single copy assay, cell-associated-DNA, cell-associated RNA) or soluble markers of inflammation. These findings suggest that higher systemic ARV exposure may not impact HIV persistence or inflammation. [ABSTRACT FROM AUTHOR]

Adequate distribution of antiretroviral drugs to infected cells in HIV patients is critical for viral suppression. In humans and primates, HIV- and SIV-infected CD4 T cells in adipose tissues have recently been identified as reservoirs for infectious virus. To better characterize adipose tissue as a pharmacological sanctuary for HIV-infected cells, in vitro experiments were conducted to assess antiretroviral drug efficacy in the presence of adipocytes, and drug penetration in adipose tissue cells (stromal-vascular-fraction cells and mature adipocytes) was examined in treated humans and monkeys. Co-culture experiments between HIV-1-infected CD4 T cells and primary human adipocytes showed that adipocytes consistently reduced the antiviral efficacy of the nucleotide reverse transcriptase inhibitor tenofovir and its prodrug forms tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). In HIV-infected persons, LC-MS/MS analysis of intracellular lysates derived from adipose tissue stromal-vascular-fraction cells or mature adipocytes suggested that integrase inhibitors penetrate adipose tissue, whereas penetration of nucleoside/nucleotide reverse transcriptase inhibitors such as TDF, emtricitabine, abacavir, and lamivudine is restricted. The limited distribution and functions of key antiretroviral drugs within fat depots may contribute to viral persistence in adipose tissue. [ABSTRACT FROM AUTHOR]

Levonorgestrel (LNG) is a synthetic progestin that is available in oral contraceptive tablets, a subdermal implant, and an intrauterine system for contraception. LNG pharmacokinetics are a pivotal determinant of contraceptive efficacy and essential in assessing drug-drug interactions influencing LNG exposure following different routes of LNG administration. A highly sensitive LC-MS/MS method was developed and validated to quantify levonorgestrel in human plasma. Liquid-liquid extraction was utilized with a sample volume of 500 μL to extract levonorgestrel from plasma. Chromatographic separation of LNG was achieved with a Fortis™ C18 (3 μm: 100 mm × 2.1 mm) reverse phase analytical column. The mobile phases consisted of de-ionized water plus 0.1% NH 4 OH (100:0.1%, v/v) (A), and methanol plus 0.1% NH 4 OH (100:0.1%, v/v) (B) delivered as a gradient at a flow rate of 400 μL/min. Detection of LNG and internal standard (D-(−)-norgestrel-d7) was achieved using positive polarity mode monitoring at 313.2–245.2 amu and 320.1–251.2 amu, respectively. The assay was linear over the calibration range of 49.6 to 1500 pg/mL. This method was used to quantify plasma LNG released by subdermal implant in support of a drug interaction study among women with HIV receiving efavirenz- or nevirapine-based antiretroviral therapy. [ABSTRACT FROM AUTHOR]

Background: HIV-positive women receiving efavirenz-based ART and levonorgestrel contraceptive implants are at risk of low levonorgestrel exposure and unintended pregnancy. Objectives: To investigate clinically applicable dose-adjustment strategies to overcome the known drug-drug interaction (DDI) between levonorgestrel and efavirenz, using a physiologically based pharmacokinetic (PBPK) modelling-based approach. Methods: A PBPK model was qualified against clinical data to predict levonorgestrel plasma concentrations when standard-dose (150 mg) levonorgestrel implants were administered alone (control group), as well as when standard-dose or increased-dose (300 mg) levonorgestrel implants were coadministered with either 600 or 400 mg of efavirenz. Results: No difference was seen between in vivo clinical and PBPK-model-simulated levonorgestrel plasma con-centrations (P> 0.05). Simulated levonorgestrel plasma concentrations were ~50% lower at 48 weeks postimplant-placement in virtual individuals receiving standard-dose levonorgestrel with either 600 or 400 mg of efavirenz compared with the control group (efavirenz:control geometric mean ratio = 0.42 and 0.49, respectively). Conversely, increased-dose levonorgestrel in combination with either 600 or 400 mg of efavirenz was sufficient to restore levonorgestrel concentrations to levels similar to those observed in the 150 mg levonorgestrel control group 48 weeks post-implant-placement (efavirenz:control geometric mean ratio = 0.86 and 1.03, respectively). Conclusions: These results suggest that the clinically significant DDI between efavirenz and levonorgestrel is likely to persist despite efavirenz dose reduction, whereas dose escalation of implantable levonorgestrel may represent a successful clinical strategy to circumvent efavirenz-levonorgestrel DDIs and will be of use to inform clinical trial design to assess coadministration of efavirenz and levonorgestrel implants. [ABSTRACT FROM AUTHOR]

• A LC-MS/MS method was developed and validated for nine antiretrovirals. • Ammonium hydroxide was used to remedy adsorption issues caused by polypropylene based collection tubes. • The assay was linear over the calibration range of 1 to 250 ng/mL for all analytes. A highly sensitive LC-MS/MS methods were developed and validated to quantify nine antiretrovirals (atazanavir [ATV], tenofovir [TFV], emtricitabine [FTC], darunavir [DRV], dolutegravir [DTG], efavirenz [EFV], lamivudine [3TC], raltegravir [RAL], and ritonavir [RTV]) in human cerebral spinal fluid (CSF). The approach remedies adsorption issues caused by polypropylene based sample collection tubes. 1% ammonium hydroxide in methanol was added in an amount equal to the volume of each quality control (QC) or patient sample. Protein precipitation was utilized with a CSF sample volume of 100 μL and a 100 μL of methanol:ACN and vortexed. Chromatographic separation was achieved with a 3 × 100 ACE® C18 column for ATV, DRV, DTG, EFV, RTV and RAL, and a 2 × 100 Polar RP column for TFV/FTC/3TC. Mobile phase was methanol:water:formic acid (70:30:0.1, v/v/v) for ATV, DRV, DTG, EFV and RTV (10 uL injection, flow rate: 1.00 mL/min), ACN:water:formic acid (35:65:0.1, v/v/v) for RAL (50 uL injection, flow rate: 1.00 mL/min), ACN:water:formic acid (2:98:0.1, v/v/v) for TFV, FTC and 3TC (50 uL injection, flow rate: 0.35 mL/min). Column temperature was 40° C across all assays. The mass spectrometer was operated in positive, multiple-reaction-monitoring (MRM) mode with electrospray ionization (ESI) for all analytes with the exception of EFV, which was operated in negative, MRM mode with ESI. The assay was linear over the calibration range of 1 to 250 ng/mL for all analytes. The addition of 1% ammonium hydroxide in sample tubes overcame up to 44% negative bias in QC samples and allowed the methods to meet full validation criteria. [ABSTRACT FROM AUTHOR]

We evaluated the pharmacokinetics of double-dose levonorgestrel (LNG) implants to overcome the drug–drug interaction with efavirenz-based antiretroviral therapy (ART). We conducted a nonrandomized, open-label, parallel-group, longitudinal pharmacokinetic study among Ugandan women ages 18–45 years. Participants with HIV on ART containing efavirenz 600 mg received 300 mg of LNG implants (Jadelle®, Bayer, New Zealand): 300LNG+ART group. We compared our outcomes with women without HIV using standard dose, 150 mg of LNG implants: 150LNG group. The implant was placed on day zero in both groups, and we quantified plasma LNG concentrations over 48 weeks post implant insertion. LNG pharmacokinetic parameters were estimated using noncompartmental techniques. Our primary outcome was the geometric mean ratio with 90% confidence intervals of LNG area under the concentration–time curve over 24 weeks (AUC 0–24w) between groups. Demographic data were described as median (interquartile range). A secondary outcome compared between-group percent of LNG concentrations ≥300 pg/mL, a minimum threshold selected a priori based on observed pregnancies in Ugandan women on standard-dose LNG implants plus efavirenz. We enrolled 27 women in the 300LNG+ART group (34 [28.0 to 40.5] years and 61.0 [49.8–66.0] kg) and 19 women in the 150LNG group (33 [30.0 to 34.5] years and 64.9 [59.0 to 74.5] kg). LNG AUC 0–24w was 34% lower for 300LNG+ART versus 150LNG (geometric mean 9998 vs. 15,231 pg*week/mL, respectively [geometric mean ratio 0.66 (90% confidence intervals, 0.54 to 0.80)]). The percentage of participants with LNG concentrations ≥300 pg/mL was not statistically different between groups at week 24 (300LNG+ART: 74.1%; 150LNG: 89.5%; p = 0.27). Double-dose LNG implant did not completely overcome the drug–drug interaction with efavirenz. In women using ART containing efavirenz, placing two implant systems (300 mg) did not normalize LNG pharmacokinetics compared with the standard-dose implant (150 mg), and some women had evidence of ovulatory activity. Alternative ART without drug–drug interactions, such as dolutegravir, is recommended with contraceptive implants. [ABSTRACT FROM AUTHOR]

Dolutegravir (DTG), elvitegravir (EVG) and raltegravir (RAL) are members of the latest class of antiretrovirals (ARVs) that have become available to treat human immunodeficiency virus (HIV) infection: integrase strand transfer inhibitors (INSTIs). INSTIs are potent inhibitors of the HIV integrase enzyme, with protein binding-adjusted concentration inhibiting viral replication by 90/95 % [IC90/95] values in the low nanogram per millilitre range, and they retain antiviral activity against strains of HIV with acquired resistance to other classes of ARVs. Each of the INSTIs has unique pharmacokinetic/pharmacodynamic properties, influencing its role in clinical use in specific subsets of patients. RAL and DTG have minimal drug-drug interaction profiles, as their metabolism has minimal cytochrome P450 (CYP) involvement. Conversely, EVG metabolism occurs primarily via CYP3A4 and requires pharmacokinetic boosting to achieve systemic exposures amenable to once-daily dosing. EVG and DTG have the added benefit of availability of fixed-dose combination tablets, allowing for convenient and simplified ARV regimens. RAL is the only INSTI to be listed as a preferred agent in the current US perinatal treatment guidelines. All three INSTIs are recommended regimens for treatment-naïve individuals in the US adult and adolescent HIV treatment guidelines. This review summarizes and compares the pharmacokinetics and pharmacodynamics of the INSTIs, and describes specific pharmacokinetic considerations for special patient conditions: hepatic impairment, renal dysfunction, pregnancy and co-infections. [ABSTRACT FROM AUTHOR]

Objectives: The testes are a potential viral sanctuary site for HIV-1 infection. Our study aims to provide insight into the expression and localization of key drug transporters and metabolic enzymes relevant to ART in this tissue compartment.Methods: We characterized gene and protein expression of 12 representative drug transporters and two metabolic enzymes in testicular tissue samples obtained from uninfected (n = 8) and virally suppressed HIV-1-infected subjects on ART (n = 5) and quantified antiretroviral drug concentrations in plasma and testicular tissues using LC/MS/MS from HIV-1-infected subjects.Results: Our data demonstrate that key ABC drug transporters (permeability glycoprotein, multidrug-resistance protein 1, 2 and 4, and breast cancer resistance protein), solute carrier transporters (organic anion transporting polypeptides 1B1 and 2B1, organic anion transporter 1, concentrative nucleoside transporter 1, equilibrative nucleoside transporter 2) and cytochrome P450 metabolic enzymes (CYP3A4 and CYP2D6) previously shown to interact with many commonly used antiretroviral drugs are expressed at the mRNA and protein level in the testes of both subject groups and localize primarily at the blood-testis barrier, with no significant differences between the two groups. Furthermore, we observed that PIs known to be substrates for ATP-binding cassette membrane transporters, displayed variable testicular tissue penetration, with darunavir concentrations falling below therapeutic values. In contrast, the NRTIs emtricitabine, lamivudine and tenofovir displayed favourable tissue penetration, reaching concentrations comparable to plasma levels. We also demonstrated that nuclear receptors, peroxisome proliferator-activated receptors α and γ exhibited higher gene expression in the testicular tissue compared with pregnane X receptor and constitutive androstane receptor, suggesting a potential regulatory pathway governing drug transporter and metabolic enzyme expression in this tissue compartment.Conclusions: Our data suggest the testes are a complex pharmacological compartment that can restrict the distribution of certain antiretroviral drugs and potentially contribute to HIV-1 persistence. [ABSTRACT FROM AUTHOR]