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Antiviral Research Aug 2023Remdesivir is a nucleotide prodrug with preclinical efficacy against lethal Nipah virus infection in African green monkeys when administered 1 day post inoculation (dpi)...
Remdesivir is a nucleotide prodrug with preclinical efficacy against lethal Nipah virus infection in African green monkeys when administered 1 day post inoculation (dpi) (Lo et al., 2019). Here, we determined whether remdesivir treatment was still effective when treatment administration initiation was delayed until 3 dpi. Three groups of six African green monkeys were inoculated with a lethal dose of Nipah virus, genotype Bangladesh. On 3 dpi, one group received a loading dose of 10 mg/kg remdesivir followed by daily dosing with 5 mg/kg for 11 days, one group received 10 mg/kg on 12 consecutive days, and the remaining group received an equivalent volume of vehicle solution. Remdesivir treatment initiation on 3 dpi provided partial protection from severe Nipah virus disease that was dose dependent, with 67% of animals in the high dose group surviving the challenge. However, remdesivir treatment did not prevent clinical disease, and surviving animals showed histologic lesions in the brain. Thus, early administration seems critical for effective remdesivir treatment during Nipah virus infection.
Topics: Animals; Chlorocebus aethiops; Henipavirus Infections; Brain; Adenosine Monophosphate; Alanine; Nipah Virus
PubMed: 37356729
DOI: 10.1016/j.antiviral.2023.105658 -
Pharmacology 2021The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiology of COVID-19 pandemic, resulted in significant harm to the affected countries in every... (Review)
Review
BACKGROUND
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiology of COVID-19 pandemic, resulted in significant harm to the affected countries in every aspect of life. The virus infected over 139 million patients and resulted in over 2.9 million deaths until April 16, 2021. New variants of this virus were identified that spread rapidly worldwide.
SUMMARY
Remdesivir, a prodrug of adenosine nucleotide analog, is an antiviral with a broad spectrum of activity that was tested on SARS and Middle East respiratory syndrome infections. In vitro studies conducted on SARS-CoV-2 revealed that remdesivir inhibited viral replication with high selectivity index in cell cultures. In vivo studies showed that remdesivir reduced viral load in bronchoalveolar lavage fluid and attenuated pulmonary infiltrates in infected animals. Further, remdesivir showed promising results in terms of clinical improvement, shortening the recovery time, mortality rate, and the duration of oxygen need, despite that some clinical trials did not reveal significant effect on remdesivir use. Several studies showed positive results of remdesivir against the new variants. Key Messages: Remdesivir showed a promising beneficial effect against new variants of SARS-CoV-2, but more clinical evidence is needed to confirm this effect.
Topics: Adenosine Monophosphate; Alanine; Animals; Antiviral Agents; COVID-19; Humans; Pandemics; Randomized Controlled Trials as Topic; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 34515227
DOI: 10.1159/000518440 -
Clinical Pharmacokinetics May 2021Remdesivir (RDV, Veklury) is a once-daily, nucleoside ribonucleic acid polymerase inhibitor of severe acute respiratory syndrome coronavirus 2 replication. Remdesivir... (Review)
Review
Remdesivir (RDV, Veklury) is a once-daily, nucleoside ribonucleic acid polymerase inhibitor of severe acute respiratory syndrome coronavirus 2 replication. Remdesivir has been granted approvals in several countries for use in adults and children hospitalized with severe coronavirus disease 2019 (COVID-19). Inside the cell, remdesivir undergoes metabolic activation to form the intracellular active triphosphate metabolite, GS-443902 (detected in peripheral blood mononuclear cells), and ultimately, the renally eliminated plasma metabolite GS-441524. This review discusses the pre-clinical pharmacology of RDV, clinical pharmacokinetics, pharmacodynamics/concentration-QT analysis, rationale for dose selection for treatment of patients with COVID-19, and drug-drug interaction potential based on available in vitro and clinical data in healthy volunteers. Following single-dose intravenous administration over 2 h of an RDV solution formulation across the dose range of 3-225 mg in healthy participants, RDV and its metabolites (GS-704277and GS-441524) exhibit linear pharmacokinetics. Following multiple doses of RDV 150 mg once daily for 7 or 14 days, major metabolite GS-441524 accumulates approximately 1.9-fold in plasma. Based on pharmacokinetic bridging from animal data and available human data in healthy volunteers, the RDV clinical dose regimen of a 200-mg loading dose on day 1 followed by 100-mg maintenance doses for 4 or 9 days was selected for further evaluation of pharmacokinetics and safety. Results showed high intracellular concentrations of GS-443902 suggestive of efficient conversion from RDV into the triphosphate form, and further supporting this clinical dosing regimen for the treatment of COVID-19. Mathematical drug-drug interaction liability predictions, based on in vitro and phase I data, suggest RDV has low potential for drug-drug interactions, as the impact of inducers or inhibitors on RDV disposition is minimized by the parenteral route of administration and extensive extraction. Using physiologically based pharmacokinetic modeling, RDV is not predicted to be a clinically significant inhibitor of drug-metabolizing enzymes or transporters in patients infected with COVID-19 at therapeutic RDV doses.
Topics: Adenosine; Adenosine Monophosphate; Adult; Alanine; Animals; Antiviral Agents; Area Under Curve; Dose-Response Relationship, Drug; Drug Interactions; Furans; Half-Life; Humans; Metabolic Clearance Rate; Pyrroles; SARS-CoV-2; Triazines; COVID-19 Drug Treatment
PubMed: 33782830
DOI: 10.1007/s40262-021-00984-5 -
Journal of Medical Virology Jan 2021
Topics: Adenosine Monophosphate; Alanine; Antibodies, Monoclonal, Humanized; Cytokine Release Syndrome; Humans; Receptors, Interleukin-6; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 32492200
DOI: 10.1002/jmv.26117 -
Nature Communications Jan 2021Remdesivir is the only FDA-approved drug for the treatment of COVID-19 patients. The active form of remdesivir acts as a nucleoside analog and inhibits the RNA-dependent...
Remdesivir is the only FDA-approved drug for the treatment of COVID-19 patients. The active form of remdesivir acts as a nucleoside analog and inhibits the RNA-dependent RNA polymerase (RdRp) of coronaviruses including SARS-CoV-2. Remdesivir is incorporated by the RdRp into the growing RNA product and allows for addition of three more nucleotides before RNA synthesis stalls. Here we use synthetic RNA chemistry, biochemistry and cryo-electron microscopy to establish the molecular mechanism of remdesivir-induced RdRp stalling. We show that addition of the fourth nucleotide following remdesivir incorporation into the RNA product is impaired by a barrier to further RNA translocation. This translocation barrier causes retention of the RNA 3'-nucleotide in the substrate-binding site of the RdRp and interferes with entry of the next nucleoside triphosphate, thereby stalling RdRp. In the structure of the remdesivir-stalled state, the 3'-nucleotide of the RNA product is matched and located with the template base in the active center, and this may impair proofreading by the viral 3'-exonuclease. These mechanistic insights should facilitate the quest for improved antivirals that target coronavirus replication.
Topics: Adenosine Monophosphate; Alanine; Antiviral Agents; Aptamers, Nucleotide; Coronavirus RNA-Dependent RNA Polymerase; Nucleotides; RNA, Viral; RNA-Dependent RNA Polymerase; SARS-CoV-2; Virus Replication; COVID-19 Drug Treatment
PubMed: 33436624
DOI: 10.1038/s41467-020-20542-0 -
Indian Journal of Pharmacology 2020
Topics: Adenosine Monophosphate; Alanine; Anti-Inflammatory Agents; Antiviral Agents; Dexamethasone; Drug Approval; Legislation, Drug; Pandemics; COVID-19 Drug Treatment
PubMed: 33666185
DOI: 10.4103/ijp.ijp_32_21 -
Biomolecules Oct 2022An intramolecular interaction between the p53 transactivation and DNA binding domains inhibits DNA binding. To study this autoinhibition, we used a fragment of p53,...
An intramolecular interaction between the p53 transactivation and DNA binding domains inhibits DNA binding. To study this autoinhibition, we used a fragment of p53, referred to as ND WT, containing the N-terminal transactivation domains (TAD1 and TAD2), a proline rich region (PRR), and the DNA binding domain (DBD). We mutated acidic, nonpolar, and aromatic amino acids in TAD2 to disrupt the interaction with DBD and measured the effects on DNA binding affinity at different ionic strengths using fluorescence anisotropy. We observed a large increase in DNA binding affinity for the mutants consistent with reduced autoinhibition. The ΔΔG between DBD and ND WT for binding a consensus DNA sequence is -3.0 kcal/mol at physiological ionic strength. ΔΔG increased to -1.03 kcal/mol when acidic residues in TAD2 were changed to alanine (ND DE) and to -1.13 kcal/mol when all the nonpolar residues, including W53/F54, were changed to alanine (ND NP). These results indicate there is some cooperation between acidic, nonpolar, and aromatic residues from TAD2 to inhibit DNA binding. The dependence of DNA binding affinity on ionic strength was used to predict excess counterion release for binding both consensus and scrambled DNA sequences, which was smaller for ND WT and ND NP with consensus DNA and smaller for scrambled DNA overall. Using size exclusion chromatography, we show that the ND mutants have similar Stokes radii to ND WT suggesting the mutants disrupt autoinhibition without changing the global structure.
Topics: Tumor Suppressor Protein p53; Protein Binding; Protein Domains; DNA; Alanine; Binding Sites
PubMed: 36358908
DOI: 10.3390/biom12111558 -
The FEBS Journal Jun 2023Alanine racemases (ALRs) are essential for d-alanine (d-Ala) production in bacteria, and many ALRs have a conserved carbamylated lysine residue in the active site....
Alanine racemases (ALRs) are essential for d-alanine (d-Ala) production in bacteria, and many ALRs have a conserved carbamylated lysine residue in the active site. Although short-chain carboxylates inhibit ALRs harbouring this lysine residue as substrate analogues, in an ALR variant with an alanine residue at this position, carboxylates behave as activators; however, this activation mechanism remains unclear. Here, we performed kinetic and structural analyses of U1ALR, an ALR from Latilactobacillus sakei UONUMA harbouring a glycine residue (Gly134) in the site of the carbamylated lysine residue. U1ALR was activated by various carboxylates and also by a G134K mutation, both of which caused a significant decrease in K , indicating an increase in substrate affinity. The U1ALR crystal structure revealed the presence of an acetate molecule bound in a position and at an orientation resembling the conformation of the carbamylated lysine side chain observed in the structures of other ALRs. These results suggest a regulatory mechanism for U1ALR activity involving two carboxylate-binding sites: one with high affinity near Gly134, where an acetate molecule is observed in the crystal structure and carboxylate binding results in enzyme activation; the other is the substrate-binding site, where carboxylate binding inhibits enzyme activity. Furthermore, we observed no carboxylate/G134K-mediated activation in the presence of d-Ala at high concentrations, implying that d-Ala also exhibits low-affinity binding in the first carboxylate-binding site and prevents carboxylate/G134K-induced activation. Such regulation of enzyme activity by carboxylates and d-Ala may be ubiquitous in many ALRs from lactic acid bacteria sharing the same sequence characteristics.
Topics: Alanine Racemase; Alanine; Lysine; Binding Sites; Catalytic Domain; Carboxylic Acids; Kinetics
PubMed: 36732053
DOI: 10.1111/febs.16745 -
Acta Pharmacologica Sinica Jul 2021Remdesivir (RDV) exerts anti-severe acute respiratory coronavirus 2 activity following metabolic activation in the target tissues. However, the pharmacokinetics and...
Remdesivir (RDV) exerts anti-severe acute respiratory coronavirus 2 activity following metabolic activation in the target tissues. However, the pharmacokinetics and tissue distributions of the parent drug and its active metabolites have been poorly characterized to date. Blood and tissue levels were evaluated in the current study. After intravenous administration of 20 mg/kg RDV in mice, the concentrations of the parent drug, nucleotide monophosphate (RMP) and triphosphate (RTP), as well as nucleoside (RN), in the blood, heart, liver, lung, kidney, testis, and small intestine were quantified. In blood, RDV was rapidly and completely metabolized and was barely detected at 0.5 h, similar to RTP, while its metabolites RMP and RN exhibited higher blood levels with increased residence times. The area under the concentration versus time curve up to the last measured point in time (AUC) values of RMP and RN were 4558 and 136,572 h∙nM, respectively. The maximum plasma concentration (C) values of RMP and RN were 2896 nM and 35,819 nM, respectively. Moreover, RDV presented an extensive distribution, and the lung, liver and kidney showed high levels of the parent drug and metabolites. The metabolic stabilities of RDV and RMP were also evaluated using lung, liver, and kidney microsomes. RDV showed higher clearances in the liver and kidney than in the lung, with intrinsic clearance (CL) values of 1740, 1253, and 127 mL/(min∙g microsomal protein), respectively.
Topics: Adenosine Monophosphate; Alanine; Animals; Antiviral Agents; COVID-19; Kidney; Liver; Lung; Male; Mice; Nucleosides; Nucleotides; Polyphosphates; SARS-CoV-2; Tissue Distribution; COVID-19 Drug Treatment
PubMed: 33041326
DOI: 10.1038/s41401-020-00537-9 -
Journal of Clinical Pharmacology Feb 2023The US Food and Drug Administration is committed to the development of effective antiviral regimens for pediatric patients with coronavirus disease 2019 (COVID-19),...
The US Food and Drug Administration is committed to the development of effective antiviral regimens for pediatric patients with coronavirus disease 2019 (COVID-19), including infants and neonates. On April 25, 2022, the approved indication of remdesivir (RDV) was expanded to include pediatric patients 28 days and older and weighing at least 3 kg with positive results of direct severe acute respiratory syndrome coronavirus 2 viral testing, who are: Hospitalized, or Not hospitalized and have mild to moderate COVID-19 and are at high risk for progression to severe COVID-19, including hospitalization or death. Given the similar course of COVID-19 in adults and pediatric patients, the approval of RDV for use in pediatric patients is supported by the safety and efficacy data from adequate and well-controlled phase 3 trials in adults and adolescents; and by the safety and pharmacokinetic data from a single-arm, open-label, phase 2/3 pediatric clinical trial of 53 pediatric patients at least 28 days of age and weighing at least 3 kg with confirmed severe acute respiratory syndrome coronavirus 2 infection and mild, moderate, or severe COVID-19. At the time of the April 25, 2022, approval action, the US Food and Drug Administration also revoked the emergency use authorization for RDV that previously covered this pediatric population. This article summarizes key issues and regulatory considerations involved in the RDV COVID-19 pediatric development program, including the evolution of the emergency use authorization issued for RDV as results from registrational studies became available, and discusses lessons learned.
Topics: Adult; Infant; Infant, Newborn; Adolescent; Humans; Child; COVID-19; COVID-19 Drug Treatment; SARS-CoV-2; Adenosine Monophosphate; Alanine; Antiviral Agents
PubMed: 36149807
DOI: 10.1002/jcph.2158