Chemotherapy in pediatric brain tumor and the challenge of the blood-brain barrier

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.

Safety and efficacy of inhaled interferon-β1a (SNG001) in adults with mild-to-moderate COVID-19: a randomized, controlled, phase II trial

Background

With the emergence of SARS-CoV-2 variants resistant to monoclonal antibody therapies and limited global access to therapeutics, the evaluation of novel therapeutics to prevent progression to severe COVID-19 remains a critical need.

Methods

Safety, clinical and antiviral efficacy of inhaled interferon-β1a (SNG001) were evaluated in a phase II randomized controlled trial on the ACTIV-2/A5401 platform (ClinicalTrials.govNCT04518410). Adult outpatients with confirmed SARS-CoV-2 infection within 10 days of symptom onset were randomized and initiated either orally inhaled nebulized SNG001 given once daily for 14 days (n = 110) or blinded pooled placebo (n = 110) between February 10 and August 18, 2021.

Findings

The proportion of participants reporting premature treatment discontinuation was 9% among SNG001 and 13% among placebo participants. There were no differences between participants who received SNG001 or placebo in the primary outcomes of treatment emergent Grade 3 or higher adverse events (3.6% and 8.2%, respectively), time to symptom improvement (median 13 and 9 days, respectively), or proportion with unquantifiable nasopharyngeal SARS-CoV-2 RNA at days 3 (28% [26/93] vs. 39% [37/94], respectively), 7 (65% [60/93] vs. 66% [62/94]) and 14 (91% [86/95] vs. 91% [83/81]). There were fewer hospitalizations with SNG001 (n = 1; 1%) compared with placebo (n = 7; 6%), representing an 86% relative risk reduction (p = 0.07). There were no deaths in either arm.

Interpretation

In this trial, SNG001 was safe and associated with a non-statistically significant decrease in hospitalization for COVID-19 pneumonia.

Funding

The ACTIV-2 platform study is funded by the NIH. Research reported in this publication was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award Number UM1 AI068634, UM1 AI068636 and UM1 AI106701. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

CD8+ cells and small viral reservoirs facilitate post-ART control of SIV replication in M3+ Mauritian cynomolgus macaques initiated on ART two weeks post-infection

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.

Phase 2 Safety and Antiviral Activity of SAB-185, a Novel Polyclonal Antibody Therapy for Nonhospitalized Adults With COVID-19

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.

Quantification of nine antiretroviral drugs in cerebrospinal fluid: An approach to overcome sample collection tube adsorption

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.

ACE-2, TMPRSS2, and Neuropilin-1 Receptor Expression on Human Brain Astrocytes and Pericytes and SARS-CoV-2 Infection Kinetics

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.

Safety and Efficacy of Combination SARS-CoV-2 Neutralizing Monoclonal Antibodies Amubarvimab Plus Romlusevimab in Nonhospitalized Patients With COVID-19

BACKGROUND

Development of safe and effective SARS-CoV-2 therapeutics is a high priority. Amubarvimab and romlusevimab are noncompeting anti-SARS-CoV-2 monoclonal antibodies with an extended half-life.

OBJECTIVE

To assess the safety and efficacy of amubarvimab plus romlusevimab.

DESIGN

Randomized, placebo-controlled, phase 2 and 3 platform trial. (ClinicalTrials.gov: NCT04518410).

SETTING

Nonhospitalized patients with COVID-19 in the United States, Brazil, South Africa, Mexico, Argentina, and the Philippines.

PATIENTS

Adults within 10 days onset of symptomatic SARS-CoV-2 infection who are at high risk for clinical progression.

INTERVENTION

Combination of monoclonal antibodies amubarvimab plus romlusevimab or placebo.

MEASUREMENTS

Nasopharyngeal and anterior nasal swabs for SARS-CoV-2, COVID-19 symptoms, safety, and progression to hospitalization or death.

RESULTS

Eight-hundred and seven participants who initiated the study intervention were included in the phase 3 analysis. Median age was 49 years (quartiles, 39 to 58); 51% were female, 18% were Black, and 50% were Hispanic or Latino. Median time from symptom onset at study entry was 6 days (quartiles, 4 to 7). Hospitalizations and/or death occurred in 9 (2.3%) participants in the amubarvimab plus romlusevimab group compared with 44 (10.7%) in the placebo group, with an estimated 79% reduction in events (P < 0.001). This reduction was similar between participants with 5 or less and more than 5 days of symptoms at study entry. Grade 3 or higher treatment-emergent adverse events through day 28 were seen less frequently among participants randomly assigned to amubarvimab plus romlusevimab (7.3%) than placebo (16.1%) (P < 0.001), with no severe infusion reactions or drug-related serious adverse events.

LIMITATION

The study population was mostly unvaccinated against COVID-19 and enrolled before the spread of Omicron variants and subvariants.

CONCLUSION

Amubarvimab plus romlusevimab was safe and significantly reduced the risk for hospitalization and/or death among nonhospitalized adults with mild to moderate SARS-CoV-2 infection at high risk for progression to severe disease.

PRIMARY FUNDING SOURCE

National Institute of Allergy and Infectious Diseases of the National Institutes of Health.

A novel 4-cell in-vitro blood-brain barrier model and its characterization by confocal microscopy and TEER measurement

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.

Safety and Efficacy of Combined Tixagevimab and Cilgavimab Administered Intramuscularly or Intravenously in Nonhospitalized Patients With COVID-19: 2 Randomized Clinical Trials

Importance

Development of effective, scalable therapeutics for SARS-CoV-2 is a priority.

Objective

To test the efficacy of combined tixagevimab and cilgavimab monoclonal antibodies for early COVID-19 treatment.

Design, Setting, and Participants

Two phase 2 randomized blinded placebo-controlled clinical trials within the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV)-2/A5401 platform were performed at US ambulatory sites. Nonhospitalized adults 18 years or older within 10 days of positive SARS-CoV-2 test and symptom onset were eligible and were enrolled from February 1 to May 31, 2021.

Interventions

Tixagevimab-cilgavimab, 300 mg (150 mg of each component) given intravenously (IV) or 600 mg (300 mg of each component) given intramuscularly (IM) in the lateral thigh, or pooled placebo.

Main Outcomes and Measures

Coprimary outcomes were time to symptom improvement through 28 days; nasopharyngeal SARS-CoV-2 RNA below the lower limit of quantification (LLOQ) on days 3, 7, or 14; and treatment-emergent grade 3 or higher adverse events through 28 days.

Results

A total of 229 participants were randomized for the IM study and 119 were randomized for the IV study. The primary modified intention-to-treat population included 223 participants who initiated IM tixagevimab-cilgavimab (n = 106) or placebo treatment (n = 117) (median age, 39 [IQR, 30-48] years; 113 [50.7%] were men) and 114 who initiated IV tixagevimab-cilgavimab (n = 58) or placebo treatment (n = 56) (median age, 44 [IQR, 35-54] years; 67 [58.8%] were women). Enrollment in the IV study was stopped early based on a decision to focus on IM product development. Participants were enrolled at a median of 6 (IQR, 4-7) days from COVID-19 symptom onset. Significant differences in time to symptom improvement were not observed for IM tixagevimab-cilgavimab vs placebo or IV tixagevimab-cilgavimab vs placebo. A greater proportion in the IM tixagevimab-cilgavimab arm (69 of 86 [80.2%]) than placebo (62 of 96 [64.6%]) had nasopharyngeal SARS-CoV-2 RNA below LLOQ at day 7 (adjusted risk ratio, 1.33 [95% CI, 1.12-1.57]) but not days 3 and 14; the joint test across time points favored treatment (P = .003). Differences in the proportion below LLOQ were not observed for IV tixagevimab-cilgavimab vs placebo at any of the specified time points. There were no safety signals with either administration route.

Conclusions

In these 2 phase 2 randomized clinical trials, IM or IV tixagevimab-cilgavimab was safe but did not change time to symptom improvement. Antiviral activity was more evident in the larger IM trial.

Trial Registration

ClinicalTrials.gov Identifier: NCT04518410.

CD8+ cells and small viral reservoirs facilitate post-ART control of SIV in Mauritian cynomolgus macaques

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). For six months after ART withdrawal, we observed undetectable or transient viremia in seven of eight MCMs. In vivo depletion of CD8α+ cells induced rebound in all animals, indicating the PTC was mediated, at least in part, by CD8α+ cells. We found that MCMs had smaller acute viral reservoirs than a cohort of identically infected rhesus macaques, a population that rarely develops PTC. The mechanisms by which unusually small viral reservoirs and CD8α+ cell-mediated virus suppression enable PTC can be investigated using this MHC-haplomatched MCM model. Further, defining the immunologic mechanisms that engender PTC in this model may identify therapeutic targets for inducing durable HIV remission in humans.

Ingestible sensor system for measuring, monitoring and enhancing adherence to antiretroviral therapy: An open-label, usual care-controlled, randomised trial

BACKGROUND

Co-encapsulated antiretrovirals (ARVs) with ingestible sensor (IS) has the capacity to monitor adherence in real-time using a sensor patch, a mobile device, and supporting software. We evaluated the acceptability, effectiveness, and sustainability of the IS system with real-time text reminders.

METHODS

Participants were recruited from HIV clinics in Los Angeles and were randomised 1:1 to IS or usual care (UC) group. Adherence to ARVs (primary outcome) was measured by IS system (IS group only), plasma ARV concentration, and self-report. IS-measured adherence was clustered by group-based trajectory model and was validated by ARV concentration summarized by integrated pharmacokinetic adherence measure (IPAM) score. HIV RNA viral load (VL) was compared between IS and UC group.

FINDINGS

A total of 112 (IS = 54, UC = 58) participants who completed baseline with at least one follow-up data collection were included in analyses. Overall satisfaction rate for the IS system was >90%. The IPAM score was higher (0.018, 95% CI: -0.098-0.134, p = 0.75) and VL decayed faster (-0.020, 95% CI: -0.042-0.002, p = 0.08) in the IS group compared with the UC group. The ingestible sensor system was well tolerated by study participants.

INTERPRETATION

The IS system was well accepted by participants and its use was associated with improved adherence and lower HIV RNA VL. The findings provide a potentially effective strategy for improving adherence.

FUNDING

This work was supported by grant R01-MH110056 from the National Institute of Mental Health (NIMH)/National Institutes of Health (NIH). Y. Wang was in part supported by the NIMH/NIH award T32MH080634. E. Daar was in part supported by the National Center for Advancing Translational Sciences through UCLACTSI Grant UL1TR001881. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Comparative Pharmacokinetics of Tixagevimab/Cilgavimab (AZD7442) Administered Intravenously Versus Intramuscularly in Symptomatic SARS-CoV-2 Infection

AZD7442 (Evusheld) is a combination of two human anti-severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) monoclonal antibodies (mAbs), tixagevimab (AZD8895) and cilgavimab (AZD1061). Route of administration is an important consideration to improve treatment access. We assessed pharmacokinetics (PKs) of AZD7442 absorption following 600 mg administered intramuscularly (i.m.) in the thigh compared with 300 mg intravenously (i.v.) in ambulatory adults with symptomatic COVID-19. PK analysis included 84 of 110 participants randomized to receive i.m. AZD7442 and 16 of 61 randomized to receive i.v. AZD7442. Serum was collected prior to AZD7442 administration and at 24 hours and 3, 7, and 14 days later. PK parameters were calculated using noncompartmental methods. Following 600 mg i.m., the geometric mean maximum concentration (Cmax ) was 38.19 μg/mL (range: 17.30-60.80) and 37.33 μg/mL (range: 14.90-58.90) for tixagevimab and cilgavimab, respectively. Median observed time to maximum concentration (Tmax ) was 7.1 and 7.0 days for tixagevimab and cilgavimab, respectively. Serum concentrations after i.m. dosing were similar to the i.v. dose (27-29 μg/mL each component) at 3 days. The area under the concentration-time curve (AUC)0-7d geometric mean ratio was 0.9 for i.m. vs. i.v. Participants with higher weight or body mass index were more likely to have lower concentrations with either route. Women appeared to have higher interparticipant variability in concentrations compared with men. The concentrations of tixagevimab and cilgavimab after administration i.m. to the thigh were similar to those achieved with i.v. after 3 days from dosing. Exposure in the i.m. group was 90% of i.v. over 7 days. Administration to the thigh can be considered to provide consistent mAb exposure and improve access.

Morphine suppresses peripheral responses and transforms brain myeloid gene expression to favor neuropathogenesis in SIV infection

The twin pandemics of opioid abuse and HIV infection can have devastating effects on physiological systems, including on the brain. Our previous work found that morphine increased the viral reservoir in the brains of treated SIV-infected macaques. In this study, we investigated the interaction of morphine and SIV to identify novel host-specific targets using a multimodal approach. We probed systemic parameters and performed single-cell examination of the targets for infection in the brain, microglia and macrophages. Morphine treatment created an immunosuppressive environment, blunting initial responses to infection, which persisted during antiretroviral treatment. Antiretroviral drug concentrations and penetration into the cerebrospinal fluid and brain were unchanged by morphine treatment. Interestingly, the transcriptional signature of both microglia and brain macrophages was transformed to one of a neurodegenerative phenotype. Notably, the expression of osteopontin, a pleiotropic cytokine, was significantly elevated in microglia. This was especially notable in the white matter, which is also dually affected by HIV and opioids. Increased osteopontin expression was linked to numerous HIV neuropathogenic mechanisms, including those that can maintain a viral reservoir. The opioid morphine is detrimental to SIV/HIV infection, especially in the brain.

Emergence of SARS-CoV-2 escape mutations during Bamlanivimab therapy in a phase II randomized clinical trial

SARS-CoV-2 mutations that cause resistance to monoclonal antibody (mAb) therapy have been reported. However, it remains unclear whether in vivo emergence of SARS-CoV-2 resistance mutations alters viral replication dynamics or therapeutic efficacy in the immune-competent population. As part of the ACTIV-2/A5401 randomized clinical trial (NCT04518410), non-hospitalized participants with symptomatic SARS-CoV-2 infection were given bamlanivimab (700 mg or 7,000 mg) or placebo treatment. Here¸ we report that treatment-emergent resistance mutations [detected through targeted Spike (S) gene next-generation sequencing] were significantly more likely to be detected after bamlanivimab 700 mg treatment compared with the placebo group (7% of 111 vs 0% of 112 participants, P = 0.003). No treatment-emergent resistance mutations among the 48 participants who received 7,000 mg bamlanivimab were recorded. Participants in which emerging mAb resistant virus mutations were identified showed significantly higher pretreatment nasopharyngeal and anterior nasal viral loads. Daily respiratory tract viral sampling through study day 14 showed the dynamic nature of in vivo SARS-CoV-2 infection and indicated a rapid and sustained viral rebound after the emergence of resistance mutations. Participants with emerging bamlanivimab resistance often accumulated additional polymorphisms found in current variants of concern/interest that are associated with immune escape. These results highlight the potential for rapid emergence of resistance during mAb monotherapy treatment that results in prolonged high-level respiratory tract viral loads. Assessment of viral resistance should be prioritized during the development and clinical implementation of antiviral treatments for COVID-19.

Population Pharmacokinetic Modeling and Simulation of Rifapentine Supports Concomitant Antiretroviral Therapy with Efavirenz and Non-Weight Based Dosing

The Brief Rifapentine-Isoniazid Efficacy for TB Prevention/A5279 trial demonstrated a 1-month daily regimen of rifapentine and isoniazid was noninferior to 9 months of isoniazid alone for preventing TB in persons living with HIV (PLWH). Our objective was to evaluate rifapentine pharmacokinetics in trial participants receiving antiretroviral therapy (ART) and perform simulations to compare weight-based rifapentine dosing with a standard, fixed dose. Nonlinear mixed effect modeling was used to estimate rifapentine and 25-desacetyl rifapentine population pharmacokinetic characteristics. The pharmacokinetic model was validated using a nonparametric bootstrap and visual predictive checks. Monte Carlo simulations were performed to compare weight-based and fixed dose regimens. Rifapentine and 25-desacetyl rifapentine concentrations (347 of each; 185 participants) were each described with a one-compartment model with one-way conversion between rifapentine and 25-desacetyl rifapentine. The absorption rate was nearly doubled in fed versus fasting states. Rifapentine clearance was increased 31% in those receiving efavirenz (EFV)-based versus nevirapine-based ART. Metabolite clearance was allometrically scaled with fat-free mass. Simulations showed lower rifapentine exposures with weight-based compared with fixed dosing. With 10 mg/kg weight-based regimens, 26% and 62% of simulated exposures in <35 kg and 35-45 kg weight classes were above target (AUC0 to 24 h of 257 mg*hr/L); 85% of simulated exposures across all weight classes with fixed dosing were above target. These data support fixed dosing with rifapentine 600 mg daily for TB prevention regardless of weight for PLWH 13 years or older receiving the 4-week regimen and no need for dose adjustment when given with EFV-based ART. Clinical Trials Registration. NCT01404312.

Efavirenz Pharmacokinetics and Human Immunodeficiency Virus Type 1 (HIV-1) Viral Suppression Among Patients Receiving Tuberculosis Treatment Containing Daily High-Dose Rifapentine

BACKGROUND

A 4-month regimen containing rifapentine and moxifloxacin has noninferior efficacy compared to the standard 6-month regimen for drug-sensitive tuberculosis. We evaluated the effect of regimens containing daily, high-dose rifapentine on efavirenz pharmacokinetics and viral suppression in patients with human immunodeficiency virus (HIV)-associated tuberculosis (TB).

METHODS

In the context of a Phase 3 randomized controlled trial, HIV-positive individuals already virally suppressed on efavirenz--containing antiretroviral therapy (ART) (EFV1), or newly initiating efavirenz (EFV2) received TB treatment containing rifapentine (1200 mg), isoniazid, pyrazinamide, and either ethambutol or moxifloxacin. Mid-interval efavirenz concentrations were measured (a) during ART and TB cotreatment (Weeks 4, 8, 12, and 17, different by EFV group) and (b) when ART was taken alone (pre- or post-TB treatment, Weeks 0 and 22). Apparent oral clearance (CL/F) was estimated and compared. Target mid-interval efavirenz concentrations were > 1 mg/L. Co-treatment was considered acceptable if > 80% of participants had mid-interval efavirenz concentrations meeting this target.

RESULTS

EFV1 and EFV2 included 70 and 41 evaluable participants, respectively. The geometric mean ratio comparing efavirenz CL/F with vs without TB drugs was 0.79 (90% confidence interval [CI] .72-.85) in EFV1 and 0.84 [90% CI .69-.97] in EFV2. The percent of participants with mid-interval efavirenz concentrations > 1mg/L in EFV1 at Weeks 0, 4, 8, and 17 was 96%, 96%, 88%, and 89%, respectively. In EFV2, at approximately 4 and 8 weeks post efavirenz initiation, the value was 98%.

CONCLUSIONS

TB treatment containing high-dose daily rifapentine modestly decreased (rather than increased) efavirenz clearance and therapeutic targets were met supporting the use of efavirenz with these regimens, without dose adjustment.

CLINICAL TRIALS REGISTRATION

NCT02410772.

Pharmacokinetics of levonorgestrel and etonogestrel contraceptive implants over 48 weeks with rilpivirine- or darunavir-based antiretroviral therapy

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.

Antiviral and clinical activity of bamlanivimab in a randomized trial of non-hospitalized adults with COVID-19

Anti-SARS-CoV-2 monoclonal antibodies are mainstay COVID-19 therapeutics. Safety, antiviral, and clinical efficacy of bamlanivimab were evaluated in the randomized controlled trial ACTIV-2/A5401. Non-hospitalized adults were randomized 1:1 within 10 days of COVID-19 symptoms to bamlanivimab or blinded-placebo in two dose-cohorts (7000 mg, n = 94; 700 mg, n = 223). No differences in bamlanivimab vs placebo were observed in the primary outcomes: proportion with undetectable nasopharyngeal SARS-CoV-2 RNA at days 3, 7, 14, 21, and 28 (risk ratio = 0.82-1.05 for 7000 mg [p(overall) = 0.88] and 0.81-1.21 for 700 mg [p(overall) = 0.49]), time to symptom improvement (median 21 vs 18.5 days [p = 0.97], 7000 mg; 24 vs 20.5 days [p = 0.08], 700 mg), or grade 3+ adverse events. However, bamlanivimab was associated with lower day 3 nasopharyngeal viral levels and faster reductions in inflammatory markers and viral decay by modeling. This study provides evidence of faster reductions in nasopharyngeal SARS-CoV-2 RNA levels but not shorter symptom durations in non-hospitalized adults with early variants of SARS-CoV-2.

Persistent HIV transcription and variable antiretroviral drug penetration in lymph nodes during plasma viral suppression

OBJECTIVE

The ability of antiretroviral drugs to penetrate and suppress viral replication in tissue reservoir sites is critical for HIV remission. We evaluated antiretroviral concentrations in lymph nodes and their impact on HIV transcription.

METHODS

Participants of the RV254/SEARCH010 Acute HIV Infection Cohort in Thailand were enrolled. Group 1 (n  = 6) initiated and continued antiretrovirals with two nucleoside reverse transcriptase inhibitors (NRTIs), dolutegravir (DTG) and mar- aviroc (MVC). Group 2 (n = 12) initiated antiretrovirals with two NRTIs as well as efavirenz and were switched to two NRTIs as well as DTG. Antiretroviral concentrations were measured by mass spectroscopy. HIV RNA+ and DNA+ cells were measured by in-situ hybridization.

RESULTS

All participants were MSM. At lymph node biopsy, all had plasma HIV RNA less than 20 copies/ml. Group 2 had longer durations of antiretroviral and DTG use (medians of 135 and 63 weeks, respectively) compared with Group 1 (median 44 weeks for both). TFV-DP, 3TC-TP, DTG and MVC were quantifiable in all lymph node samples from participants receiving those drugs versus carbovir-triphosphate (CBV-TP) in four out of 14. Median ratios of lymph node to peripheral blood concentrations were DTG, 0.014; MVC, 6.9; CBV-TP, 0.38; 3TC-TP, 0.32; and TFV-DP, 3.78. Median inhibitory quotients [ratios of lymph node concentrations to in-vitro inhibitory levels (IC50-or-90)] were DTG, 0.8; MVC, 38.8; CBV-TP, 0.5; 3TC- TP, 4.1; and TFV-DP, 1.8. Ongoing viral transcription was detected in lymph node of all participants. Median lymph node RNA+ cells were 71 350 versus 99 750 cells/g for Groups 1 and 2, respectively (P = 0.111).

CONCLUSION

MVC has enhanced lymph node penetration and thereby may contribute to more complete viral suppression in the lymph node.

Efficacy of Losartan in Hospitalized Patients With COVID-19-Induced Lung Injury: A Randomized Clinical Trial

Importance

SARS-CoV-2 viral entry may disrupt angiotensin II (AII) homeostasis, contributing to COVID-19 induced lung injury. AII type 1 receptor blockade mitigates lung injury in preclinical models, although data in humans with COVID-19 remain mixed.

Objective

To test the efficacy of losartan to reduce lung injury in hospitalized patients with COVID-19.

Design, Setting, and Participants

This blinded, placebo-controlled randomized clinical trial was conducted in 13 hospitals in the United States from April 2020 to February 2021. Hospitalized patients with COVID-19 and a respiratory sequential organ failure assessment score of at least 1 and not already using a renin-angiotensin-aldosterone system (RAAS) inhibitor were eligible for participation. Data were analyzed from April 19 to August 24, 2021.

Interventions

Losartan 50 mg orally twice daily vs equivalent placebo for 10 days or until hospital discharge.

Main Outcomes and Measures

The primary outcome was the imputed arterial partial pressure of oxygen to fraction of inspired oxygen (Pao2:Fio2) ratio at 7 days. Secondary outcomes included ordinal COVID-19 severity; days without supplemental o2, ventilation, or vasopressors; and mortality. Losartan pharmacokinetics and RAAS components (AII, angiotensin-[1-7] and angiotensin-converting enzymes 1 and 2)] were measured in a subgroup of participants.

Results

A total of 205 participants (mean [SD] age, 55.2 [15.7] years; 123 [60.0%] men) were randomized, with 101 participants assigned to losartan and 104 participants assigned to placebo. Compared with placebo, losartan did not significantly affect Pao2:Fio2 ratio at 7 days (difference, -24.8 [95%, -55.6 to 6.1]; P = .12). Compared with placebo, losartan did not improve any secondary clinical outcomes and led to fewer vasopressor-free days than placebo (median [IQR], 9.4 [9.1-9.8] vasopressor-free days vs 8.7 [8.2-9.3] vasopressor-free days).

Conclusions and Relevance

This randomized clinical trial found that initiation of orally administered losartan to hospitalized patients with COVID-19 and acute lung injury did not improve Pao2:Fio2 ratio at 7 days. These data may have implications for ongoing clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT04312009.

Bamlanivimab reduces nasopharyngeal SARS-CoV-2 RNA levels but not symptom duration in non-hospitalized adults with COVID-19: A Phase 2 Randomized Clinical Trial

Importance

The antiviral activity and efficacy of anti-SARS-CoV-2 monoclonal antibody (mAb) therapies to accelerate recovery from COVID-19 is important to define.

Objective

To determine safety and efficacy of the mAb bamlanivimab to reduce nasopharyngeal (NP) SARS-CoV-2 RNA levels and symptom duration.

Design

ACTIV-2/A5401 is a randomized, blinded, placebo-controlled platform trial. Two dose cohorts were enrolled between August 19 and November 17, 2020 for phase 2 evaluation: in the first, participants were randomized 1:1 to bamlanivimab 7000 mg versus placebo, and in the second to bamlanivimab 700 mg versus placebo. Randomization was stratified by time from symptom onset (≤ or >5 days) and risk of progression to severe COVID-19 ("higher" vs "lower").

Setting

Multicenter trial conducted at U.S. sites.

Participants

Non-hospitalized adults ≥18 years of age with positive SARS-CoV-2 antigen or nucleic acid test within 7 days, ≤10 days of COVID-19 symptoms, and with oxygen saturation ≥92% within 48 hours prior to study entry.

Intervention

Single infusion of bamlanivimab (7000 or 700 mg) or placebo.

Main Outcomes and Measures

Detection of NP SARS-CoV-2 RNA at days 3, 7, 14, 21, and 28, time to improvement of all of 13 targeted COVID-19 symptoms by daily self-assessment through day 28, and grade 3 or higher treatment emergent adverse events (TEAEs) through day 28. Secondary measures included quantitative NP SARS-CoV-2 RNA, all-cause hospitalizations and deaths (composite), area under the curve of symptom scores from day 0 through day 28, plasma bamlanivimab concentrations, plasma and serum inflammatory biomarkers, and safety through week 24.

Results

Ninety-four participants were enrolled to the 7000 mg cohort and 223 to the 700 mg cohort and initiated study intervention. The proportion meeting protocol criteria for "higher" risk for COVID-19 progression was 42% and 51% for the 7000 and 700 mg cohort, respectively. Median time from symptom onset at study entry for both cohorts was 6 days. There was no difference in the proportion with undetectable NP SARS-CoV-2 RNA at any post-treatment timepoints (risk ratio compared to placebo, 0.82-1.05 for 7000 mg dose [overall p=0.88] and 0.81-1.21 for 700 mg dose [overall p=0.49]), time to symptom improvement (median of 21 vs 18.5 days, p=0.97, for 7000 mg bamlanivimab vs placebo and 24 vs 20.5 days, p=0.08, for 700 mg bamlanivimab vs placebo), or grade 3+ TEAEs with either dose compared to placebo. Median NP SARS-CoV-2 RNA levels were lower at day 3 and C-reactive protein, ferritin, and fibrinogen levels significantly reduced at days 7 and 14 for bamlanivimab 700 mg compared to placebo, with similar trends observed for bamlanivimab 7000 mg. Viral decay modeling supported more rapid decay with bamlanivimab compared to placebo.

Conclusions and Relevance

Treatment with bamlanivimab 7000 mg and 700 mg was safe and compared to placebo led to more rapid reductions in NP SARS-CoV-2 RNA and inflammatory biomarkers, but did not decrease time to symptom improvement. The clinical utility of mAbs for outcomes other than hospitalizations and deaths is uncertain.

Trial Registration

ClinicalTrials.gov Identifier: NCT04518410.

Diminished Peripheral CD29hi Cytotoxic CD4+ T Cells Are Associated With Deleterious Effects During SIV Infection

Cytotoxic CD4+ T cells (CD4+ CTLs) limit HIV pathogenesis, as evidenced in elite controllers (a subset of individuals who suppress the virus without the need for therapy). CD4+ CTLs have also been shown to kill HIV-infected macrophages. However, little is known about their contribution towards HIV persistence, how they are affected following exposure to immune modulators like morphine, and what factors maintain their frequencies and function. Further, the lack of robust markers to identify CD4+ CTLs in various animal models limits understanding of their role in HIV pathogenesis. We utilized various PBMC samples obtained from SIV infected and cART treated rhesus macaques exposed to morphine or saline and subjected to flow cytometry evaluations. Thereafter, we compared and correlated the expression of CD4+ CTL-specific markers to viral load and viral reservoir estimations in total CD4+ T cells. We found that CD29 could be reliably used as a marker to identify CD4+ CTLs in rhesus macaques since CD29hi CD4+ T cells secrete higher cytotoxic and proinflammatory cytokines following PMA/ionomycin or gag stimulation. In addition, this immune cell subset was depleted during untreated SIV infection. Strikingly, we also observed that early initiation of cART reconstitutes depleted CD29hi CD4+ T cells and restores their function. Furthermore, we noted that morphine exposure reduced the secretion of proinflammatory cytokines/cytotoxic molecules in CD29hi CD4+ T cells. Lastly, increased functionality of CD29hi CD4+ T cells as depicted by elevated levels of either IL-21 or granzyme B hi T Bet+ gag specific responses were linked to limiting the size of the replication-competent reservoir during cART treatment. Collectively, our data suggest that CD4+ CTLs are crucial in limiting SIV pathogenesis and persistence.

Comparative Clinical Pharmacokinetics and Pharmacodynamics of HIV-1 Integrase Strand Transfer Inhibitors: An Updated Review

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 IC_90/95 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 5'-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.

Emergence of SARS-CoV-2 Resistance with Monoclonal Antibody Therapy

Resistance mutations to monoclonal antibody (mAb) therapy has been reported, but in the non-immunosuppressed population, it is unclear if in vivo emergence of SARS-CoV-2 resistance mutations alters either viral replication dynamics or therapeutic efficacy. In ACTIV-2/A5401, non-hospitalized participants with symptomatic SARS-CoV-2 infection were randomized to bamlanivimab (700mg or 7000mg) or placebo. Treatment-emergent resistance mutations were significantly more likely detected after bamlanivimab 700mg treatment than placebo (7% of 111 vs 0% of 112 participants, P=0.003). There were no treatment-emergent resistance mutations among the 48 participants who received bamlanivimab 7000mg. Participants with emerging mAb resistant virus had significantly higher pre-treatment nasopharyngeal and anterior nasal viral load. Intensive respiratory tract viral sampling revealed the dynamic nature of SARS-CoV-2 evolution, with evidence of rapid and sustained viral rebound after emergence of resistance mutations, and worsened symptom severity. Participants with emerging bamlanivimab resistance often accumulated additional polymorphisms found in current variants of concern/interest and associated with immune escape. These results highlight the potential for rapid emergence of resistance during mAb monotherapy treatment, resulting in prolonged high level respiratory tract viral loads and clinical worsening. Careful virologic assessment should be prioritized during the development and clinical implementation of antiviral treatments for COVID-19.

Safety and Pharmacokinetics of Double-Dose Lopinavir/Ritonavir + Rifampin Versus Lopinavir/Ritonavir + Daily Rifabutin for Treatment of Human Immunodeficiency Virus-Tuberculosis Coinfection

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.

Therapeutic implications of SARS-CoV-2 dysregulation of the gut-brain-lung axis

The emergence and rapid spread of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused over 180 million confirmed cases resulting in over 4 million deaths worldwide with no clear end in sight for the coronavirus disease 19 (COVID-19) pandemic. Most SARS-CoV-2 exposed individuals experience mild to moderate symptoms, including fever, cough, fatigue, and loss of smell and taste. However, many individuals develop pneumonia, acute respiratory distress syndrome, septic shock, and multiorgan dysfunction. In addition to these primarily respiratory symptoms, SARS-CoV-2 can also infiltrate the central nervous system, which may damage the blood-brain barrier and the neuron's synapses. Resultant inflammation and neurodegeneration in the brain stem can further prevent efferent signaling to cranial nerves, leading to the loss of anti-inflammatory signaling and normal respiratory and gastrointestinal functions. Additionally, SARS-CoV-2 can infect enterocytes resulting in gut damage followed by microbial dysbiosis and translocation of bacteria and their byproducts across the damaged epithelial barrier. As a result, this exacerbates pro-inflammatory responses both locally and systemically, resulting in impaired clinical outcomes. Recent evidence has highlighted the complex interactions that mutually modulate respiratory, neurological, and gastrointestinal function. In this review, we discuss the ways SARS-CoV-2 potentially disrupts the gut-brain-lung axis. We further highlight targeting specific responses to SARS-CoV-2 for the development of novel, urgently needed therapeutic interventions. Finally, we propose a prospective related to the individuals from Low- and Middle-Income countries. Here, the underlying propensity for heightened gut damage/microbial translocation is likely to result in worse clinical outcomes during this COVID-19 pandemic.

Antiretroviral Drug Transporters and Metabolic Enzymes in Circulating Monocytes and Monocyte-Derived Macrophages of ART-Treated People Living With HIV and HIV-Uninfected Individuals

ABSTRACT

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 LC-MS/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 HIV-negative 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.

Intramuscular and subcutaneous administration of antiretroviral drugs, compared with oral, enhances delivery to lymphoid tissues in BALB/c mice

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.

Report of the National Institutes of Health SARS-CoV-2 Antiviral Therapeutics Summit

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.

Antiretroviral hair levels, self-reported adherence, and virologic failure in second-line regimen patients in resource-limited settings

OBJECTIVE

To evaluate associations between hair antiretroviral hair concentrations as an objective, cumulative adherence metric, with self-reported adherence and virologic outcomes.

DESIGN

Analysis of cohort A of the ACTG-A5288 study. These patients in resource-limited settings were failing second-line protease inhibitor-based antiretroviral therapy (ART) but were susceptible to at least one nucleoside reverse transcriptase inhibitor (NRTI) and their protease inhibitor, and continued taking their protease inhibitor-based regimen.

METHODS

Antiretroviral hair concentrations in participants taking two NRTIs with boosted atazanavir (n = 69) or lopinavir (n = 112) were analyzed at weeks 12, 24, 36 and 48 using liquid-chromatography--tandem-mass-spectrometry assays. Participants' self-reported percentage of doses taken in the previous month; virologic failure was confirmed HIV-1 RNA at least 1000 copies/ml at week 24 or 48.

RESULTS

From 181 participants with hair samples (61% women, median age: 39 years; CD4+ cell count: 167 cells/μl; HIV-1 RNA: 18 648 copies/ml), 91 (50%) experienced virologic failure at either visit. At 24 weeks, median hair concentrations were 2.95 [interquartile range (IQR) 0.49-4.60] ng/mg for atazanavir, 2.64 (IQR 0.73--7.16) for lopinavir, and 0.44 (IQR 0.11--0.76) for ritonavir. Plasma HIV-1 RNA demonstrated inverse correlations with hair levels (rs -0.46 to -0.74) at weeks 24 and 48. Weaker associations were seen with self-reported adherence (rs -0.03 to -0.24). Decreasing hair concentrations were significantly associated with virologic failure, the hazard ratio (95% CI) for ATV, LPV, and RTV were 0.69 (0.56-0.86), 0.77 (0.68-0.87), and 0.12 (0.06-0.27), respectively.

CONCLUSION

Protease inhibitor hair concentrations showed stronger associations with subsequent virologic outcomes than self-reported adherence in this cohort. Hair adherence measures could identify individuals at risk of second-line treatment failure in need of interventions.

Cross-validation of a high-performance liquid chromatography nevirapine plasma assay in a resource-limited setting in Zimbabwe

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.

Nevirapine pharmacokinetics in HIV-infected persons receiving rifapentine and isoniazid for TB prevention

BACKGROUND

The use of rifamycin antibiotics for TB prevention carries a risk of detrimental drug-drug interactions with concomitantly used ART.

OBJECTIVES

To evaluate the interaction of the antiretroviral drug nevirapine in combination with 4 weeks of daily rifapentine and isoniazid for TB prevention in people living with HIV.

METHODS

Participants were individuals enrolled in the BRIEF-TB study receiving nevirapine and randomized to the rifapentine/isoniazid arm of the study. Participants provided sparse pharmacokinetic (PK) sampling at baseline and weeks 2 and 4 for trough nevirapine determination. Nevirapine apparent oral clearance (CL/F) was estimated and the geometric mean ratio (GMR) of CL/F prior to and during rifapentine/isoniazid was calculated.

RESULTS

Seventy-eight participants had evaluable PK data: 61 (78%) female, 51 (65%) black non-Hispanic and median (range) age of 40 (13-66) years. Median (IQR) nevirapine trough concentrations were: week 0, 7322 (5266-9302) ng/mL; week 2, 5537 (3552-8462) ng/mL; and week 4, 5388 (3516-8243) ng/mL. Sixty out of 78 participants (77%) had nevirapine concentrations ≥3000 ng/mL at both week 2 and 4. Median (IQR) nevirapine CL/F values were: week 0 pre-rifapentine/isoniazid, 2.03 (1.58-2.58) L/h; and during rifapentine/isoniazid, 2.62 (1.81-3.42) L/h. The GMR (90% CI) for nevirapine CL/F was 1.30 (1.26-1.33).

CONCLUSIONS

The CL/F of nevirapine significantly increased with concomitant rifapentine/isoniazid. The decrease in nevirapine trough concentrations during rifapentine/isoniazid therapy suggests induction of nevirapine metabolism, consistent with known rifapentine effects. The magnitude of this drug-drug interaction suggests daily rifapentine/isoniazid for TB prevention should not be co-administered with nevirapine-containing ART.

Plasma and intracellular pharmacokinetics of tenofovir disoproxil fumarate and emtricitabine in transgender women receiving feminizing hormone therapy

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.

Role of toll-like receptor 7/8 pathways in regulation of interferon response and inflammatory mediators during SARS-CoV2 infection and potential therapeutic options

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) is the causative agent of Corona Virus Disease 2019 (COVID-19). Lower production of type I and III interferons and higher levels of inflammatory mediators upon SARS-CoV2 infection contribute to COVID-19 pathogenesis. Optimal interferon production and controlled inflammation are essential to limit COVID-19 pathogenesis. However, the aggravated inflammatory response observed in COVID-19 patients causes severe damage to the host and frequently advances to acute respiratory distress syndrome (ARDS). Toll-like receptor 7 and 8 (TLR7/8) signaling pathways play a central role in regulating induction of interferons (IFNs) and inflammatory mediators in dendritic cells. Controlled inflammation is possible through regulation of TLR mediated response without influencing interferon production to reduce COVID-19 pathogenesis. This review focuses on inflammatory mediators that contribute to pathogenic effects and the role of TLR pathways in the induction of interferon and inflammatory mediators and their contribution to COVID-19 pathogenesis. We conclude that potential TLR7/8 agonists inducing antiviral interferon response and controlling inflammation are important therapeutic options to effectively eliminate SARS-CoV2 induced pathogenesis. Ongoing and future studies may provide additional evidence on their safety and efficacy to treat COVID-19 pathogenesis.

Cryopreservation of microglia enables single-cell RNA sequencing with minimal effects on disease-related gene expression patterns

Microglia play a key role in brain development, normal homeostasis, and neurodegenerative disorders. Single-cell technologies have led to important findings about microglia, with many animal model studies using single-cell RNA sequencing (scRNA-seq), whereas most human specimen studies using archived frozen brains for single-nucleus RNA sequencing (snRNA-seq). However, microglia compose a small proportion of the total brain tissue; snRNAseq depletes expression of microglia activation genes that characterize many diseases. Here we examine the use of purified, cryopreserved microglia for scRNA-seq. Comparison of scRNA-seq on paired fresh and cryopreserved microglia from rhesus monkeys revealed a high level of correlation of gene expression between the two conditions. Disease-related genes were relatively unaffected, but an increase in immediate-early gene expression was present in cryopreserved cells. Regardless, changes in immediate-early gene expression are still detectable. Cryopreservation of microglia is a suitable procedure for prospectively archiving samples.

The Contributions of Clinical Pharmacology to HIV Cure Research

Combination antiretroviral therapy (ART) can suppress plasma HIV-RNA to < 50 copies/mL, decrease HIV transmission, reduce mortality, and improve quality of life for people living with HIV. ART cannot, however, eliminate HIV from an infected individual. The primary barrier to cure HIV infection is the multiple reservoir sites, including adipose tissue, bone marrow, central nervous system, liver, lungs, male and female reproductive system, secondary lymph nodes, and gut-associated lymphoid tissue, established 1 to 2 weeks after acquisition of HIV. Additional challenges include understanding the mechanism(s) by which HIV is maintained at low or undetectable levels and developing treatments that will eradicate or produce a sustained suppression of virus without ART. To date, the most extensive clinical investigations of cure strategies have been the shock-and-kill approach using histone deacetylase inhibitors (HDACis) to induce reactivation of latent HIV. Despite evidence for HIV latency reversal, HDACis alone have not decreased the size of the latent reservoir. Clinical pharmacologic explanations for these results include a low inhibitory quotient (i.e., low potency) within the reservoir sites and intrinsic (e.g., sex differences and reservoir size) and extrinsic (physiochemical and pharmacokinetic drug characteristics) factors. We offer an outline of desired clinical pharmacologic attributes for therapeutics intended for clinical HIV cure research and call for research teams to have early and ongoing involvement of clinical pharmacologists. We believe such a collective effort will provide a solid scientific basis and hope for reaching the goal of a cure for HIV infection.

In-vitro Immunomodulatory activity of Azadirachta indica A.Juss. Ethanol: water mixture against HIV associated chronic CD4+ T-cell activation/ exhaustion

BACKGROUND

In Sub-Saharan Africa, herbal therapy continues to be utilized for HIV-1 disease management. However, the therapeutic benefits of these substances remain ambiguous. To date, little is known about the effects of these plant extracts on chronic CD4 + T-cell activation and exhaustion which is partly driven by HIV-1 associated microbial translocation.

METHODS

Effects of Azadirachta indica, Momordica foetida and Moringa oleifera ethanol: water mixtures on cell viability were evaluated using the Guava PCA system. Then, an in-vitro cell culture model was developed to mimic CD4+ T cell exposures to antigens following HIV-1 microbial translocation. In this, peripheral blood mononuclear cells (PBMCs) isolated from HIV negative (n = 13), viral load < 1000 copies per mL (n = 10) and viral load > 1000 copies per mL (n = 6) study participants from rural Uganda were treated with Staphylococcus enterotoxin B (SEB). Then, the candidate plant extract (A. indica) was added to test the potential to inhibit corresponding CD4+ T cell activation. Following BD Facs Canto II event acquisition, variations in %CD38, %CD69, Human Leukocyte Antigen -DR (HLA-DR), Programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3), interferon gamma (IFN γ) and interleukin 2 (IL-2) CD4 + T cell expression were evaluated.

RESULTS

Following exposure to SEB, only A. indica demonstrated a concentration-dependent ability to downregulate the levels of CD4 + T cell activation. At the final concentration of 0.500 μg/mL of A. indica, a significant downregulation of CD4 + CD38 + HLA-DR+ expression was observed in HIV negative (p < 0.0001) and both HIV infected groups (P = 0.0313). This plant extract also significantly lowered SEB induced % CD4+ T cell HLADR, PD-1 and Tim-3 levels. PD-1 and CD69 markers were only significantly downmodulated in only the HIV negative ((p = 0.0001 and p = 0.0078 respectively) and viral load< 1000 copies per ml (p = 0.0078) groups.

CONCLUSION

A. indica exhibited the in-vitro immunomodulatory potential to inhibit the continuum of SEB induced CD4+ T-cell activation/ exhaustion without impacting general T-cell specific functions such as cytokine secretion. Additional studies are needed to confirm A. indica as a source of natural products for targeting persistent immune activation and inflammation during ART.

Pharmacogenetic interactions of rifapentine plus isoniazid with efavirenz or nevirapine

OBJECTIVES

The effect of rifapentine plus isoniazid on efavirenz pharmacokinetics was characterized in AIDS Clinical Trials Group protocol A5279 (NCT01404312). The present analyses characterize pharmacogenetic interactions between these drugs, and with nevirapine.

METHODS

A subset of HIV-positive individuals receiving efavirenz- or nevirapine-containing antiretroviral therapy in A5279 underwent pharmacokinetic evaluations at baseline, and again weeks 2 and 4 after initiating daily rifapentine plus isoniazid. Associations with polymorphisms relevant to efavirenz, nevirapine, isoniazid, and rifapentine pharmacokinetics were assessed.

RESULTS

Of 128 participants, 101 were evaluable for associations with rifapentine and its active 25-desacetyl metabolite, 87 with efavirenz, and 38 with nevirapine. In multivariable analyses, NAT2 slow acetylators had greater week 4 plasma concentrations of rifapentine (P = 2.6 × 10) and 25-desacetyl rifapentine (P = 7.0 × 10) among all participants, and in efavirenz and nevirapine subgroups. NAT2 slow acetylators also had greater plasma efavirenz and nevirapine concentration increases from baseline to week 4, and greater decreases from baseline in clearance. CYP2B6 poor metabolizers had greater efavirenz concentrations at all weeks and greater nevirapine concentrations at baseline. None of 47 additional polymorphisms in 11 genes were significantly associated with pharmacokinetics.

CONCLUSIONS

Among HIV-positive individuals receiving efavirenz or nevirapine, and who then initiated rifapentine plus isoniazid in A5279, NAT2 slow acetylators had greater rifapentine and 25-desacetyl rifapentine concentrations, and greater increases from baseline in plasma efavirenz and nevirapine concentrations. These associations are likely mediated by greater isoniazid exposure in NAT2 slow acetylators.

HIV-1 Integrase Inhibitors: A Comparative Review of Efficacy and Safety

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.

Pharmacologic approaches to HIV-associated neurocognitive disorders

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.

Transcriptomic approach predicts a major role for transforming growth factor beta type 1 pathway in L-Dopa-induced dyskinesia in parkinsonian rats

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.

Assessing the lymphoid tissue bioavailability of antiretrovirals in human primary lymphoid endothelial cells and in mice

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.

Immuno-epidemiology and pathophysiology of coronavirus disease 2019 (COVID-19)

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.

The Lymphoid Tissue Pharmacokinetics of Tenofovir Disoproxil Fumarate and Tenofovir Alafenamide in HIV-Infected Persons

The secondary lymphoid tissues (LT), lymph nodes (LN) and gut-associated lymphoid tissue are the primary sites of HIV replication and where the latent pool of virus is maintained. We compared the pharmacokinetics of tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) in LT of 13 HIV-infected persons receiving a TDF-containing antiretroviral regimen who subsequently switched to a TAF-containing regimen. Study participants were on stable antiretroviral therapy for ≥12 months with plasma HIV-RNA < 48 copies/mL for 6 months before enrollment and entry CD4 cell counts > 300 cells/µL. Intracellular concentrations of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) were quantified in PBMCs and in mononuclear cells obtained from LN, ileum and rectal tissues. With TAF, the TFV-DP concentrations in PBMCs and LN were 7.3-fold and 6.4-fold higher (ratios of geometric means of TAF to TDF), respectively, compared with TDF; ileal and rectal concentrations, however, were lower with geometric mean ratios of 0.14 and 0.18, respectively. A statistically significant relationship was observed between PBMC and LN concentrations of TFV-DP. During TDF-containing therapy, the expected effect of cobicistat to increase TFV plasma concentrations was observed, as were higher TFV-DP concentrations in PBMCs and mononuclear cells from LN, ileum and rectal tissues. The higher TFV-DP concentrations achieved with TAF in the LN provides the first human correlate of the observation in animals that TAF produced higher tenofovir LN concentrations. The ability to increase LN concentrations allows investigations of whether antiretroviral regimens with improved LN pharmacokinetics elicit a more complete virologic response in that compartment.

Assessing whether isoniazid is essential during the first 14 days of tuberculosis therapy: a phase 2a, open-label, randomised controlled trial

Background

Clinical studies suggest that isoniazid contributes rapid bacterial killing during the initial two days of tuberculosis treatment but that isoniazid's activity declines significantly after day three. We conducted a 14-day phase IIa open label, randomized trial to assess the essentiality of isoniazid in standard tuberculosis therapy.

Methods

A total of 69 adults with newly diagnosed sputum-positive tuberculosis from the South African Western Cape region were enrolled and randomized to a four-arm parallel assignment model. Participants were followed for 14 days as inpatients at either the University of Cape Town Lung Institute or at the TASK Applied Science clinical research organization. All arms received standard daily rifampicin, ethambutol, and pyrazinamide but differed as follows: isoniazid only on days one and two (n=17), isoniazid on days one and two then moxifloxacin on days three through 14 (n=16), no isoniazid (n=18), and a control group that received isoniazid for all 14 days (standard therapy, n=18). The primary endpoint was the rate of colony forming unit (CFU) decline during the first 14 days of treatment.

Results

For 62 participants analyzed, the initial 14-day mean daily fall in log₁₀ CFU (95% CI) was 0·14 (0·11, 0·18) for participants receiving isoniazid for two days only; 0·13 (0·09, 0·17) for participants receiving isoniazid for two days followed by moxifloxacin; 0·12 (0·08, 0·15) for those not receiving isoniazid; and 0·13 (0·09, 0·16) for the standard therapy group.

Conclusions

The 14 day EBA for the combination rifampicin, ethambutol, and pyrazinamide was not significantly changed by the addition of isoniazid for the first two days or for the first 14 days of treatment. In a post hoc analysis, significantly higher day-two EBAs were observed for all groups among participants with higher baseline sputum CFUs. Our finding that INH does not contribute to EBA suggests that INH could be replaced with another drug during standard treatment to improve efficacy and decrease rates of resistance to first-line drugs. (Funded by the NIH AIDS Clinical Trial Groups and NIH; A5307 ClinicalTrials.gov number, NCT01589497).

High-dose rifapentine with or without moxifloxacin for shortening treatment of pulmonary tuberculosis: Study protocol for TBTC study 31/ACTG A5349 phase 3 clinical trial

INTRODUCTION

Phase 2 clinical trials of tuberculosis treatment have shown that once-daily regimens in which rifampin is replaced by high dose rifapentine have potent antimicrobial activity that may be sufficient to shorten overall treatment duration. Herein we describe the design of an ongoing phase 3 clinical trial testing the hypothesis that once-daily regimens containing high dose rifapentine in combination with other anti-tuberculosis drugs administered for four months can achieve cure rates not worse than the conventional six-month treatment regimen.

METHODS/DESIGN

S31/A5349 is a multicenter randomized controlled phase 3 non-inferiority trial that compares two four-month regimens with the standard six-month regimen for treating drug-susceptible pulmonary tuberculosis in HIV-negative and HIV-positive patients. Both of the four-month regimens contain high-dose rifapentine instead of rifampin, with ethambutol replaced by moxifloxacin in one regimen. All drugs are administered seven days per week, and under direct observation at least five days per week. The primary outcome is tuberculosis disease-free survival at twelve months after study treatment assignment. A total of 2500 participants will be randomized; this gives 90% power to show non-inferiority with a 6.6% margin of non-inferiority.

DISCUSSION

This phase 3 trial formally tests the hypothesis that augmentation of rifamycin exposures can shorten tuberculosis treatment to four months. Trial design and standardized implementation optimize the likelihood of obtaining valid results. Results of this trial may have important implications for clinical management of tuberculosis at both individual and programmatic levels.

TRIAL REGISTRATION

NCT02410772. Registered 8 April 2015,https://www.clinicaltrials.gov/ct2/show/NCT02410772?term=02410772&rank=1.

Real-Time and Wireless Assessment of Adherence to Antiretroviral Therapy With Co-Encapsulated Ingestion Sensor in HIV-Infected Patients: A Pilot Study

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.

Pharmacokinetics of Coencapsulated Antiretrovirals with Ingestible Sensors

We investigated the use of a system with an ingestible sensor (Proteus Digital Health Feedback system) coencapsulated with antiretrovirals (ARVs) to measure real-time adherence. To assess the safety and impact, if any, coencapsulation might have on ARV concentrations, we evaluated the pharmacokinetics of ARVs coencapsulated with an ingestible sensor for eight commonly used fixed-dose combination ARVs: emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF); FTC/tenofovir alafenamide (TAF); efavirenz (EFV)/FTC/TDF; abacavir (ABC)/lamivudine (3TC); dolutegravir (DTG)/ABC/3TC; rilpivirine (RPV)/TAF/FTC; elvitegravir (EVG)/cobicistat (COBI)/FTC/TAF; and bictegravir (BIC)/FTC/TAF. The steady-state apparent peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) were determined from plasma concentrations measured at predose, 1, 2, 4, and 6 h postdose, and compared with literature values. A total of 49 unique patients on stable regimens for at least 12 weeks with undetectable viral loads were recruited. Cmax and AUC values were not statistically significantly different from literature values for all of the formulations except the Cmax of FTC/TDF, Cmax of BIC, and the Cmax of RPV. In a subsequent evaluation of FTC/TDF and BIC/FTC/TAF using a crossover design, the geometric mean ratio (GMR) between the coencapsulated and the unencapsulated formulations for FTC/TDF were the following: FTC, 84.6% (90% confidence interval [CI] 66.6-107.4) for AUC and 77.5% (60.1-99.9) for Cmax. For tenofovir (TFV), the GMR was 96.2% (90% CI 89.2-103.8) for AUC and 87.3% (64.2-118.7) for Cmax. The GMR for BIC (from the BIC/FTC/TAF formulation) was 98.0% (90% CI 84.5-113.5) for AUC and 89.9% (84.5-95.7) for Cmax. The observed deviation in FTC/TDF (Truvada) may be due to participant characteristics, fasted/fed conditions, and/or random variation and may warrant further investigations with a larger sample size. These findings provide assurance for use of coencapsulated ARVs for future HIV treatment-adherence research.