Publications by authors named "Samit Joshi"

Article Synopsis
  • * This maturation process transforms initially immature virions into infectious particles by forming a fullerene core that contains genomic RNA and alters the surface distribution of the Env glycoprotein, which is vital for viral entry into host cells.
  • * The article discusses host factors influencing maturation, the use of advanced microscopic technologies to study this process, and the development of antivirals targeting virion maturation for improved treatment options.
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GSK3640254 (GSK'254) is a novel HIV-1 maturation inhibitor with pharmacokinetics supporting once-daily (QD) therapy for HIV-1 treatment. This thorough QT/corrected QT (QTc) study evaluated the effect of GSK'254 on cardiac repolarization. In this two-part, randomized study, healthy participants received GSK'254 or placebo QD for 7 days (part 1) to determine safety and pharmacokinetics of a 500-mg supratherapeutic dose.

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Aims: This phase I study investigated potential drug-drug interactions of the maturation inhibitor GSK3640254 (GSK'254) with darunavir/ritonavir (DRV/RTV) and/or etravirine (ETR).

Methods: In this randomized, open-label, single-sequence, multiple-dose study, healthy participants received GSK'254 200 mg once daily alone or coadministered with DRV/RTV 600/100 mg twice daily (BID; n = 19), ETR 200 mg BID (n = 19) or DRV/RTV 600/100 mg + ETR 200 mg BID (n = 16) under fed conditions. Primary endpoints were steady-state area under the plasma concentration-time curve from time 0 to the end of the dosing interval (AUC ) and maximum observed concentration (C ).

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Aims: GSK3640254 (GSK'254) is an HIV-1 maturation inhibitor with pharmacokinetics (PK) supporting once-daily dosing. GSK'254 will be co-administered with cytochrome P450 enzyme substrates and drug transporters, including other antiretrovirals, in people living with HIV-1 (PLWH).

Methods: In this open-label study, healthy participants received a single dose of a cocktail of eight cytochrome P450 and transporter probe substrates on Day 1, followed by a 10-day washout before receiving GSK'254 200 mg once daily from Days 11 to 20 and a single dose of cocktail + GSK'254 200 mg on Day 21.

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Seasonal influenza causes mild to severe respiratory infections and significant morbidity, especially in older adults. Transcriptomic analysis in populations across multiple flu seasons has provided insights into the molecular determinants of vaccine response. Still, the metabolic changes that underlie the immune response to influenza vaccination remain poorly characterized.

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Background: GSK3640254 (GSK'254) is a next-generation human immunodeficiency virus type 1 (HIV-1) maturation inhibitor with pharmacokinetics (PK) supporting once-daily therapy.

Methods: This phase IIa double-blind (sponsor-unblinded), randomized, placebo-controlled, adaptive study evaluated antiviral effect, safety, tolerability, and PK of once-daily GSK'254 monotherapy administered with food (moderate-fat meal) in HIV-1-positive, treatment-naive adults. In part 1, participants received GSK'254 10 or 200 mg for 10 days.

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GSK3640254 is a next-generation maturation inhibitor with demonstrated potency across HIV-1 subtypes and a high barrier to emergent resistance. This phase I, 2-part, randomized, open-label study (ClinicalTrials.gov identifier, NCT04263142) in healthy participants assessed the relative bioavailability of a single dose of GSK3640254 200 mg in tablet and capsule formulations (part 1) and the effect of food on the pharmacokinetic profile of the tablet formulation (part 2).

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Aims: GSK3640254 is a next-generation maturation inhibitor likely to be coadministered with combined oral contraceptives in HIV-positive women.

Methods: This phase I, open-label, 1-way study assessed pharmacokinetic and pharmacodynamic interactions of GSK3640254 200 mg and ethinyl oestradiol 0.03 mg/levonorgestrel 0.

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GSK3640254 is a next-generation maturation inhibitor that would likely be combined with standard antiretroviral agents to form a regimen of ≥2 fully active classes. This phase I, open-label, 2-period, 1-way study assessed potential pharmacokinetic (PK) interactions between GSK3640254 and tenofovir alafenamide/emtricitabine (TAF/FTC; including the metabolite tenofovir [TFV]) in healthy volunteers. Eligible participants received TAF/FTC 25/200 mg once daily (QD) on days 1 through 21 with a moderate-fat meal; GSK3640254 200 mg QD was added on days 15 through 21.

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Aims: GSK3640254, a novel, next-generation maturation inhibitor effective against a range of HIV polymorphisms with no cross-resistance to current antiretroviral therapy, could potentially be coadministered with dolutegravir as a 2-drug regimen. In this phase I study, pharmacokinetics and tolerability of GSK3640254 plus dolutegravir were assessed.

Methods: Healthy participants received dolutegravir 50 mg once daily (QD) on Days 1-5 in period 1, GSK3640254 200 mg QD on Days 1-7 in period 2, and dolutegravir 50 mg plus GSK3640254 200 mg QD on Days 1-7 in period 3.

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Despite advances in HIV-1 management with antiretroviral therapy, drug resistance and toxicities with multidrug regimens can result in treatment failure. Hence, there is a continuing demand for antiretroviral agents (ARVs) with novel mechanisms of action. Maturation inhibitors inhibit HIV-1 replication via a unique mechanism of action and can be combined with other ARVs.

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GSK3532795 (formerly BMS955176) is a second-generation maturation inhibitor (MI) that progressed through a Phase 2b study for treatment of HIV-1 infection. Resistance development to GSK3532795 was evaluated through in vitro methods and was correlated with information obtained in a Phase 2a proof-of-concept study in HIV-1 infected participants. Both low and high concentrations of GSK3532795 were used for selections in vitro, and reduced susceptibility to GSK3532795 mapped specifically to amino acids near the capsid/ spacer peptide 1 (SP1) junction, the cleavage of which is blocked by MIs.

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GSK3532795 (formerly known as BMS-955176) is a second-generation maturation inhibitor targeting a specific Gag cleavage site between capsid p24 and spacer peptide 1 of HIV-1. Study 205891 (previously AI468038) investigated the efficacy, safety, and dose response of GSK3532795 in treatment-naive, HIV-1-infected participants. Study 205891 (NCT02415595) was a Phase IIb, randomized, active-controlled, double-blind, international trial.

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Background: Fostemsavir is a prodrug of temsavir, an attachment inhibitor that binds to HIV-1 gp120, blocking viral attachment to host CD4 T-cells. The phase 2b trial AI438011 investigated the safety, efficacy, and dose-response of fostemsavir vs ritonavir-boosted atazanavir (ATV/r) in treatment-experienced, HIV-1-infected subjects.

Methods: Two hundred fifty-one treatment-experienced subjects with baseline (BL) susceptibility to study drugs [temsavir half-maximal inhibitory concentration (IC50) <100 nM, PhenoSense Entry assay] received fostemsavir or ATV/r, each with tenofovir disoproxil fumarate + raltegravir.

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Motivation: Systems immunology leverages recent technological advancements that enable broad profiling of the immune system to better understand the response to infection and vaccination, as well as the dysregulation that occurs in disease. An increasingly common approach to gain insights from these large-scale profiling experiments involves the application of statistical learning methods to predict disease states or the immune response to perturbations. However, the goal of many systems studies is not to maximize accuracy, but rather to gain biological insights.

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Background: Fostemsavir is a prodrug of temsavir, an attachment inhibitor that binds directly to HIV-1 gp120, blocking initial viral attachment and entry into host CD4 T-cells. Efficacy, safety and dose-response data of fostemsavir in treatment-experienced, HIV-1-infected subjects, through week 48, are reported.

Methods: AI438011 is an ongoing Phase IIb, randomized, active-controlled trial (NCT01384734).

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BMS-663068 is an oral prodrug of the HIV-1 attachment inhibitor BMS-626529, which prevents viral attachment to host CD4(+) T cells by binding to HIV-1 gp120. To guide dose selection for the phase 3 program, pharmacokinetic/pharmacodynamic modeling was performed using data from two phase 2 studies with HIV-1-infected subjects (n = 244). BMS-626529 population pharmacokinetics were described by a two-compartment model with first-order elimination from the central compartment, zero-order release of prodrug from the extended-release formulation into a hypothetical absorption compartment, and first-order absorption into the central compartment.

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Background: BMS-986001 is a thymidine analogue nucleoside reverse transcriptase inhibitor (NRTI) designed to maintain in-vitro antiviral activity while minimising off-target effects. We assessed the efficacy and safety of BMS-986001 versus tenofovir disoproxil fumarate in treatment-naive patients with HIV-1.

Methods: In this phase 2b, randomised, active-controlled trial (AI467003), we recruited treatment-naive (no current or previous exposure to an antiretroviral drug for >1 week) adults (aged at least 18 years) with HIV-1 from 47 sites across Asia, Australia, Europe, North America, South Africa, and South America.

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Background: BMS-663068 is an oral prodrug of BMS-626529, an attachment inhibitor that binds to HIV-1 gp120, blocking viral attachment to host CD4 cells. AI438011 is an ongoing trial investigating the efficacy, safety, and dose-response of BMS-663068 in treatment-experienced, HIV-1-infected patients. Herein we present the results of the primary analysis.

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By facilitating the simultaneous analysis of parameters from diverse cell lineages and biological pathways, multicolor flow cytometry is integral to many studies in human immunology-particularly those in older individuals-where sample amounts may be limiting. Studies in human cohorts require particular attention to fluorochrome panel design and procedures to standardize instrument performance; reproducible instrument conditions (over time and between centers) are crucial to accurate comparisons and conclusions in the analysis of heterogeneous groups of human subjects. Here, we describe procedures for multicolor digital flow cytometry, our experience in flow cytometry panel design and our approach in standardizing instrument performance using BD Biosciences hardware and software (BD Biosciences, San Jose, CA).

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Unlabelled: Elite controllers (ECs) are a rare group of HIV seropositive individuals who are able to control viral replication without antiretroviral therapy. The mechanisms responsible for this phenotype, however, have not been fully elucidated. In this study, we examined CD4(+) T cell resistance to HIV in a cohort of elite controllers and explored transcriptional signatures associated with cellular resistance.

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To elucidate gene expression pathways underlying age-associated impairment in influenza vaccine response, we screened young (age 21-30) and older (age≥65) adults receiving influenza vaccine in two consecutive seasons and identified those with strong or absent response to vaccine, including a subset of older adults meeting criteria for frailty. PBMCs obtained prior to vaccination (Day 0) and at day 2 or 4, day 7 and day 28 post-vaccine were subjected to gene expression microarray analysis. We defined a response signature and also detected induction of a type I interferon response at day 2 and a plasma cell signature at day 7 post-vaccine in young responders.

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Introduction: BMS-663068 is a prodrug of BMS-626529, an attachment inhibitor that binds directly to HIV-1 gp120, preventing initial viral attachment and entry into the host CD4+ T-cell. AI438011 is an ongoing, Phase IIb, randomized, active-controlled trial investigating the safety, efficacy and dose-response of BMS-663068 vs. atazanavir/ritonavir (ATV/r) in treatment-experienced (TE), HIV-1-positive subjects.

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Introduction: BMS-663068 is a prodrug of BMS-626529, an attachment inhibitor that binds directly to HIV-1 gp120, preventing initial viral attachment and entry into the host CD4+ T-cell. AI438011 is a Phase IIb, randomized, active-controlled trial investigating the safety, efficacy and dose-response of BMS-663068 versus atazanavir/ritonavir (ATV/r) in treatment-experienced (TE), HIV-1-positive subjects.

Materials And Methods: Antiretroviral TE subjects (exposure to ≥1 antiretroviral for ≥1 week) with susceptibility to all study drugs (BMS-626529 IC50 100 nM), were randomized equally to four BMS-663068 arms (400 or 800 mg, BID; 600 or 1200 mg, QD) and a control group (ATV/r 300/100 mg QD) with tenofovir disoproxil fumarate (TDF) + raltegravir (RAL).

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We evaluated in vivo innate immune responses in monocyte populations from 67 young (aged 21-30 years) and older (aged ≥65 years) adults before and after influenza vaccination. CD14(+)CD16(+) inflammatory monocytes were induced after vaccination in both young and older adults. In classical CD14(+)CD16(-) and inflammatory monocytes, production of tumor necrosis factor α and interleukin 6, as measured by intracellular staining, was strongly induced after vaccination.

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