Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 26
Filter
1.
Antimicrob Agents Chemother ; 66(6): e0022222, 2022 Jun 21.
Article in English | MEDLINE | ID: covidwho-1832332

ABSTRACT

Genetic variation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the emergence and rapid spread of multiple variants throughout the pandemic, of which Omicron is currently the predominant variant circulating worldwide. SARS-CoV-2 variants of concern/variants of interest (VOC/VOI) have evidence of increased viral transmission, disease severity, or decreased effectiveness of vaccines and neutralizing antibodies. Remdesivir (RDV [VEKLURY]) is a nucleoside analog prodrug and the first FDA-approved antiviral treatment of COVID-19. Here, we present a comprehensive antiviral activity assessment of RDV and its parent nucleoside, GS-441524, against 10 current and former SARS-CoV-2 VOC/VOI clinical isolates by nucleoprotein enzyme-linked immunosorbent assay (ELISA) and plaque reduction assay. Delta and Omicron variants remained susceptible to RDV and GS-441524, with 50% effective concentration (EC50) values 0.30- to 0.62-fold of those observed against the ancestral WA1 isolate. All other tested variants exhibited EC50 values ranging from 0.13- to 2.3-fold of the observed EC50 values against WA1. Analysis of nearly 6 million publicly available variant isolate sequences confirmed that Nsp12, the RNA-dependent RNA polymerase (RdRp) target of RDV and GS-441524, is highly conserved across variants, with only 2 prevalent changes (P323L and G671S). Using recombinant viruses, both RDV and GS-441524 retained potency against all viruses containing frequent variant substitutions or their combination. Taken together, these results highlight the conserved nature of SARS-CoV-2 Nsp12 and provide evidence of sustained SARS-CoV-2 antiviral activity of RDV and GS-441524 across the tested variants. The observed pan-variant activity of RDV supports its continued use for the treatment of COVID-19 regardless of the SARS-CoV-2 variant.


Subject(s)
COVID-19 , SARS-CoV-2 , Adenosine/analogs & derivatives , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/drug therapy , Humans , SARS-CoV-2/genetics
2.
Antiviral Res ; 203: 105329, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1819427

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the COVID-19 pandemic, has infected over 260 million people over the past 2 years. Remdesivir (RDV, VEKLURY®) is currently the only antiviral therapy fully approved by the FDA for the treatment of COVID-19. The parent nucleoside of RDV, GS-441524, exhibits antiviral activity against numerous respiratory viruses including SARS-CoV-2, although at reduced in vitro potency compared to RDV in most assays. Here we find in both human alveolar and bronchial primary cells, GS-441524 is metabolized to the pharmacologically active GS-441524 triphosphate (TP) less efficiently than RDV, which correlates with a lower in vitro SARS-CoV-2 antiviral activity. In vivo, African green monkeys (AGM) orally dosed with GS-441524 yielded low plasma levels due to limited oral bioavailability of <10%. When GS-441524 was delivered via intravenous (IV) administration, although plasma concentrations of GS-441524 were significantly higher, lung TP levels were lower than observed from IV RDV. To determine the required systemic exposure of GS-441524 associated with in vivo antiviral efficacy, SARS-CoV-2 infected AGMs were treated with a once-daily IV dose of either 7.5 or 20 mg/kg GS-441524 or IV RDV for 5 days and compared to vehicle control. Despite the reduced lung TP formation compared to IV dosing of RDV, daily treatment with IV GS-441524 resulted in dose-dependent efficacy, with the 20 mg/kg GS-441524 treatment resulting in significant reductions of SARS-CoV-2 replication in the lower respiratory tract of infected animals. These findings demonstrate the in vivo SARS-CoV-2 antiviral efficacy of GS-441524 and support evaluation of its orally bioavailable prodrugs as potential therapies for COVID-19.


Subject(s)
COVID-19 , Adenosine/analogs & derivatives , Animals , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Chlorocebus aethiops , Humans , Pandemics , SARS-CoV-2
3.
Sci Transl Med ; : eabo0718, 2022 Apr 28.
Article in English | MEDLINE | ID: covidwho-1816673

ABSTRACT

The nucleoside analog remdesivir (RDV) is a Food and Drug Administration (FDA)-approved antiviral for treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Thus, it is critical to understand factors that promote or prevent RDV resistance. We passaged SARS-CoV-2 in the presence of increasing concentrations of GS-441524, the parent nucleoside of RDV. After 13 passages, we isolated three viral lineages with phenotypic resistance as defined by increases in half-maximal effective concentration (EC50) from 2.7-to 10.4-fold. Sequence analysis identified non-synonymous mutations in nonstructural protein 12 RNA-dependent RNA polymerase (nsp12-RdRp): V166A, N198S, S759A, V792I and C799F/R. Two lineages encoded the S759A substitution at the RdRp Ser759-Asp-Asp active motif. In one lineage, the V792I substitution emerged first, then combined with S759A. Introduction of S759A and V792I substitutions at homologous nsp12 positions in murine hepatitis virus (MHV) demonstrated transferability across betacoronaviruses; introduction of these substitutions resulted in up to 38-fold RDV resistance and a replication defect. Biochemical analysis of SARS-CoV-2 RdRp encoding S759A demonstrated a roughly 10-fold decreased preference for RDV-triphosphate (RDV-TP) as a substrate, whereas nsp12-V792I diminished the uridine-triphosphate (UTP) concentration needed to overcome template-dependent inhibition associated with RDV. The in vitro-selected substitutions identified in this study were rare or not detected in the greater than 6 million publicly available nsp12-RdRp consensus sequences in the absence of RDV selection. The results define genetic and biochemical pathways to RDV resistance and emphasize the need for additional studies to define the potential for emergence of these or other RDV resistance mutations in clinical settings.

5.
Antivir Ther ; 27(2): 13596535221082773, 2022 04.
Article in English | MEDLINE | ID: covidwho-1753060

ABSTRACT

If a planned path reaches a dead-end, one can simply stop. Or one can turn around, walk back to the last intersection and take another path, or one can consider taking few paths in parallel. The last scenario is reflective of the journey of remdesivir, the first antiviral for the treatment of COVID-19, that was approved by FDA less than 10 months after the isolation of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. As of January 2022, 10 million COVID-19 patients have been treated with remdesivir worldwide, but the journey of this molecule started more than a decade earlier with the search for a cure of hepatitis C virus. The development path of remdesivir before the emergence of COVID-19 represents a valuable example of a preemptive pandemic preparedness, but the pursuit of this path would not have been possible without sustaining support of John C. Martin, whom we will sorely miss for his piercing vision, uncompromising leadership, and genuine compassion for patients suffering around the world.


Subject(s)
COVID-19 , Hepacivirus , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19/drug therapy , Humans , Pandemics , SARS-CoV-2
6.
Sci Transl Med ; 14(643): eabm3410, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1752762

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic remains uncontrolled despite the rapid rollout of safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, underscoring the need to develop highly effective antivirals. In the setting of waning immunity from infection and vaccination, breakthrough infections are becoming increasingly common and treatment options remain limited. In addition, the emergence of SARS-CoV-2 variants of concern, with their potential to escape neutralization by therapeutic monoclonal antibodies, emphasizes the need to develop second-generation oral antivirals targeting highly conserved viral proteins that can be rapidly deployed to outpatients. Here, we demonstrate the in vitro antiviral activity and in vivo therapeutic efficacy of GS-621763, an orally bioavailable prodrug of GS-441524, the parent nucleoside of remdesivir, which targets the highly conserved virus RNA-dependent RNA polymerase. GS-621763 exhibited antiviral activity against SARS-CoV-2 in lung cell lines and two different human primary lung cell culture systems. GS-621763 was also potently antiviral against a genetically unrelated emerging coronavirus, Middle East respiratory syndrome CoV (MERS-CoV). The dose-proportional pharmacokinetic profile observed after oral administration of GS-621763 translated to dose-dependent antiviral activity in mice infected with SARS-CoV-2. Therapeutic GS-621763 administration reduced viral load and lung pathology; treatment also improved pulmonary function in COVID-19 mouse model. A direct comparison of GS-621763 with molnupiravir, an oral nucleoside analog antiviral that has recently received EUA approval, proved both drugs to be similarly efficacious in mice. These data support the exploration of GS-441524 oral prodrugs for the treatment of COVID-19.


Subject(s)
COVID-19 , Coronavirus Infections , Prodrugs , Adenosine/analogs & derivatives , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Coronavirus Infections/drug therapy , Humans , Mice , Nucleosides , Parents , Prodrugs/pharmacology , Prodrugs/therapeutic use , SARS-CoV-2
7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-319173

ABSTRACT

Remdesivir is the only small-molecule antiviral approved to date for COVID-19 treatment, but its wider use is limited by intravenous delivery. An orally bioavailable remdesivir analog may boost therapeutic benefit by facilitating early administration to non-hospitalized patients. This study characterized the anti-SARS-CoV-2 efficacy of GS-621763, an oral prodrug of remdesivir parent nucleoside GS-441524. Both GS-621763 and GS-441524 inhibited SARS-CoV-2, including variants of concern (VoC) in cell culture. Oral GS-621763 was efficiently converted to plasma metabolite GS-441524, and in lungs to the triphosphate metabolite identical to that generated by remdesivir, demonstrating a consistent mechanism of activity. Twice-daily oral administration of 10 mg/kg GS-621763 reduced SARS-CoV-2 burden to near-undetectable levels. When dosed therapeutically against VoC P.1 gamma (γ), oral GS-621763 blocked virus replication and prevented transmission to untreated contact animals. These results demonstrate therapeutic efficacy of a much-needed orally bioavailable analog of remdesivir in a relevant animal model of SARS-CoV-2 infection.

8.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327574

ABSTRACT

Genetic variation of SARS-CoV-2 has resulted in the emergence and rapid spread of multiple variants throughout the pandemic, of which Omicron is currently the predominant variant circulating worldwide. SARS-CoV-2 variants of concern or interest (VOC/VOI) have evidence of increased viral transmission, disease severity, or decreased effectiveness of vaccines and neutralizing antibodies. Remdesivir (RDV, VEKLURY ® ) is a nucleoside analog prodrug and the first FDA-approved antiviral treatment of COVID-19. Here we present a comprehensive antiviral activity assessment of RDV and its parent nucleoside, GS-441524, against 10 current and former SARS-CoV-2 VOC/VOI clinical isolates by nucleoprotein ELISA and plaque reduction assay. Delta and Omicron variants remained susceptible to RDV and GS-441524, with EC 50 values 0.31 to 0.62-fold of those observed against the ancestral WA1 isolate. All other tested variants exhibited EC 50 values ranging from 0.15 to 2.3-fold of the observed EC 50 values against WA1. Analysis of nearly 6 million publicly available variant isolate sequences confirmed that Nsp12, the RNA-dependent RNA polymerase (RdRp) target of RDV and GS-441524, is highly conserved across variants with only 2 prevalent changes (P323L and G671S). Using recombinant viruses, both RDV and GS-441524 retained potency against all viruses containing frequent variant substitutions or their combination. Taken together, these results highlight the conserved nature of SARS-CoV-2 Nsp12 and provide evidence of sustained SARS-CoV-2 antiviral activity of RDV and GS-441524 across the tested variants. The observed pan-variant activity of RDV supports its continued use for the treatment of COVID-19 regardless of the SARS-CoV-2 variant.

9.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327129

ABSTRACT

The nucleoside analog remdesivir (RDV) is an FDA-approved antiviral for the treatment of SARS-CoV-2 infections, and as such it is critical to understand potential genetic determinants and barriers to RDV resistance. In this study, SARS-CoV-2 was subjected to 13 passages in cell culture with increasing concentrations of GS-441524, the parent nucleoside of RDV. At passage 13 the RDV resistance of the lineages ranged from 2.7-to 10.4-fold increase in EC50. Sequence analysis of the three lineage populations identified non-synonymous mutations in the nonstructural protein 12 RNA-dependent RNA polymerase (nsp12-RdRp): V166A, N198S, S759A, V792I and C799F/R. Two of the three lineages encoded the S759A substitution at the RdRp Ser759-Asp-Asp active motif. In one lineage, the V792I substitution emerged first then combined with S759A. Introduction of the S759A and V792I substitutions at homologous nsp12 positions in viable isogenic clones of the betacoronavirus murine hepatitis virus (MHV) demonstrated their transferability across CoVs, up to 38-fold RDV resistance in combination, and a significant replication defect associated with their introduction. Biochemical analysis of SARS-CoV-2 RdRp encoding S759A demonstrated a ~10-fold decreased preference for RDV-triphosphate (RDV-TP) as a substrate, while nsp12-V792I diminished the UTP concentration needed to overcome the template-dependent inhibition associated with RDV. The in vitro selected substitutions here identified were rare or not detected in the >6 million publicly available nsp12-RdRp consensus sequences in the absence of RDV selection. The results define genetic and biochemical pathways to RDV resistance and emphasize the need for additional studies to define the potential for emergence of these or other RDV resistance mutations in various clinical settings.

10.
Antiviral Res ; 198: 105246, 2022 02.
Article in English | MEDLINE | ID: covidwho-1639070

ABSTRACT

The utility of remdesivir treatment in COVID-19 patients is currently limited by the necessity to administer this antiviral intravenously, which has generally limited its use to hospitalized patients. Here, we tested a novel, subcutaneous formulation of remdesivir in the rhesus macaque model of SARS-CoV-2 infection that was previously used to establish the efficacy of remdesivir against this virus in vivo. Compared to vehicle-treated animals, macaques treated with subcutaneous remdesivir from 12 h through 6 days post inoculation showed reduced signs of respiratory disease, a reduction of virus replication in the lower respiratory tract, and an absence of interstitial pneumonia. Thus, early subcutaneous administration of remdesivir can protect from lower respiratory tract disease caused by SARS-CoV-2.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Lung Diseases, Interstitial/prevention & control , SARS-CoV-2/drug effects , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/pharmacokinetics , Adenosine Monophosphate/therapeutic use , Administration, Cutaneous , Alanine/administration & dosage , Alanine/pharmacokinetics , Alanine/therapeutic use , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/pharmacokinetics , Disease Models, Animal , Female , Lung/pathology , Lung/virology , Macaca mulatta , Male , Viral Load/drug effects , Virus Replication/drug effects
11.
Sci Transl Med ; 14(633): eabl8282, 2022 Feb 23.
Article in English | MEDLINE | ID: covidwho-1598975

ABSTRACT

Remdesivir (RDV) is a nucleotide analog prodrug with demonstrated clinical benefit in patients with coronavirus disease 2019 (COVID-19). In October 2020, the US FDA approved intravenous (IV) RDV as the first treatment for hospitalized COVID-19 patients. Furthermore, RDV has been approved or authorized for emergency use in more than 50 countries. To make RDV more convenient for non-hospitalized patients earlier in disease, alternative routes of administration are being evaluated. Here, we investigated the pharmacokinetics and efficacy of RDV administered by head dome inhalation in African green monkeys (AGM). Relative to an IV administration of RDV at 10 mg/kg, an approximately 20-fold lower dose administered by inhalation produced comparable concentrations of the pharmacologically active triphosphate in lower respiratory tract tissues. Distribution of the active triphosphate into the upper respiratory tract was also observed following inhaled RDV exposure. Inhalation RDV dosing resulted in lower systemic exposures to RDV and its metabolites as compared with IV RDV dosing. An efficacy study with repeated dosing of inhaled RDV in an AGM model of SARS-CoV-2 infection demonstrated reductions in viral replication in bronchoalveolar lavage fluid and respiratory tract tissues compared with placebo. Efficacy was observed with inhaled RDV administered once daily at a pulmonary deposited dose of 0.35 mg/kg beginning approximately 8 hours post-infection. Moreover, the efficacy of inhaled RDV was similar to that of IV RDV administered once at 10 mg/kg followed by 5 mg/kg daily in the same study. Together, these findings support further clinical development of inhalation RDV.


Subject(s)
COVID-19 , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Animals , Antiviral Agents/pharmacokinetics , COVID-19/drug therapy , Chlorocebus aethiops , Humans , Primates , SARS-CoV-2 , Viral Load
12.
Nat Commun ; 12(1): 6415, 2021 11 05.
Article in English | MEDLINE | ID: covidwho-1503781

ABSTRACT

Remdesivir is an antiviral approved for COVID-19 treatment, but its wider use is limited by intravenous delivery. An orally bioavailable remdesivir analog may boost therapeutic benefit by facilitating early administration to non-hospitalized patients. This study characterizes the anti-SARS-CoV-2 efficacy of GS-621763, an oral prodrug of remdesivir parent nucleoside GS-441524. Both GS-621763 and GS-441524 inhibit SARS-CoV-2, including variants of concern (VOC) in cell culture and human airway epithelium organoids. Oral GS-621763 is efficiently converted to plasma metabolite GS-441524, and in lungs to the triphosphate metabolite identical to that generated by remdesivir, demonstrating a consistent mechanism of activity. Twice-daily oral administration of 10 mg/kg GS-621763 reduces SARS-CoV-2 burden to near-undetectable levels in ferrets. When dosed therapeutically against VOC P.1 gamma γ, oral GS-621763 blocks virus replication and prevents transmission to untreated contact animals. These results demonstrate therapeutic efficacy of a much-needed orally bioavailable analog of remdesivir in a relevant animal model of SARS-CoV-2 infection.


Subject(s)
Adenosine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/drug therapy , Prodrugs/pharmacology , SARS-CoV-2/drug effects , Adenosine/pharmacology , Animals , COVID-19/metabolism , COVID-19/virology , Cell Line , Chlorocebus aethiops , Cricetinae , Disease Models, Animal , Female , Ferrets , Humans , SARS-CoV-2/isolation & purification
13.
Sci Rep ; 11(1): 19458, 2021 09 30.
Article in English | MEDLINE | ID: covidwho-1447326

ABSTRACT

Efficacious therapeutics for Ebola virus disease are in great demand. Ebola virus infections mediated by mucosal exposure, and aerosolization in particular, present a novel challenge due to nontypical massive early infection of respiratory lymphoid tissues. We performed a randomized and blinded study to compare outcomes from vehicle-treated and remdesivir-treated rhesus monkeys in a lethal model of infection resulting from aerosolized Ebola virus exposure. Remdesivir treatment initiated 4 days after exposure was associated with a significant survival benefit, significant reduction in serum viral titer, and improvements in clinical pathology biomarker levels and lung histology compared to vehicle treatment. These observations indicate that remdesivir may have value in countering aerosol-induced Ebola virus disease.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Ebolavirus/drug effects , Hemorrhagic Fever, Ebola/drug therapy , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/pharmacology , Administration, Intravenous , Aerosols , Alanine/administration & dosage , Alanine/pharmacology , Animals , Antiviral Agents/administration & dosage , Disease Models, Animal , Female , Hemorrhagic Fever, Ebola/blood , Kaplan-Meier Estimate , Liver/drug effects , Liver/virology , Lung/pathology , Lung/virology , Lymph Nodes/drug effects , Lymph Nodes/pathology , Lymph Nodes/virology , Macaca mulatta , Male , Random Allocation , Systemic Inflammatory Response Syndrome/drug therapy , Systemic Inflammatory Response Syndrome/virology , Viral Load/drug effects , Viremia/drug therapy
15.
Cell Rep ; 36(4): 109450, 2021 07 27.
Article in English | MEDLINE | ID: covidwho-1306890

ABSTRACT

Improving clinical care for individuals infected with SARS-CoV-2 variants is a global health priority. Small-molecule antivirals like remdesivir (RDV) and biologics such as human monoclonal antibodies (mAbs) have demonstrated therapeutic efficacy against SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19). It is not known whether combination RDV/mAb will improve outcomes over single-agent therapies or whether antibody therapies will remain efficacious against variants. Here, we show that a combination of two mAbs in clinical trials, C144 and C135, have potent antiviral effects against even when initiated 48 h after infection and have therapeutic efficacy in vivo against the B.1.351 variant of concern (VOC). Combining RDV and antibodies provided a modest improvement in outcomes compared with single agents. These data support the continued use of RDV to treat SARS-CoV-2 infections and the continued clinical development of the C144 and C135 antibody combination to treat patients infected with SARS-CoV-2 variants.


Subject(s)
Antibodies, Monoclonal/pharmacology , COVID-19/drug therapy , SARS-CoV-2/drug effects , Animals , Antibodies, Monoclonal/immunology , Antiviral Agents/pharmacology , Humans , Mice , SARS-CoV-2/pathogenicity
16.
Antiviral Res ; 192: 105122, 2021 08.
Article in English | MEDLINE | ID: covidwho-1283915

ABSTRACT

There are, besides remdesivir, no approved antivirals for the treatment of SARS-CoV-2 infections. To aid in the search for antivirals against this virus, we explored the use of human tracheal airway epithelial cells (HtAEC) and human small airway epithelial cells (HsAEC) grown at the air-liquid interface (ALI). These cultures were infected at the apical side with one of two different SARS-CoV-2 isolates. Each virus was shown to replicate to high titers for extended periods of time (at least 8 days) and, in particular an isolate with the D614G in the spike (S) protein did so more efficiently at 35 °C than 37 °C. The effect of a selected panel of reference drugs that were added to the culture medium at the basolateral side of the system was explored. Remdesivir, GS-441524 (the parent nucleoside of remdesivir), EIDD-1931 (the parent nucleoside of molnupiravir) and IFN (ß1 and λ1) all resulted in dose-dependent inhibition of viral RNA and infectious virus titers collected at the apical side. However, AT-511 (the free base form of AT-527 currently in clinical testing) failed to inhibit viral replication in these in vitro primary cell models. Together, these results provide a reference for further studies aimed at selecting SARS-CoV-2 inhibitors for further preclinical and clinical development.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , SARS-CoV-2/drug effects , Virus Replication/drug effects , Animals , Cell Line , Chlorocebus aethiops , Drug Evaluation, Preclinical/methods , Epithelial Cells/virology , Humans , RNA, Viral , SARS-CoV-2/isolation & purification , Vero Cells
17.
J Infect Dis ; 224(Supplement_1): S1-S21, 2021 Jul 15.
Article in English | MEDLINE | ID: covidwho-1263668

ABSTRACT

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.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , SARS-CoV-2/drug effects , Antiviral Agents/pharmacology , COVID-19/virology , Drug Development , Humans , National Institutes of Health (U.S.) , Peptide Hydrolases/metabolism , Protease Inhibitors/pharmacology , Protease Inhibitors/therapeutic use , United States , Virus Replication/drug effects
18.
J Med Chem ; 64(8): 5001-5017, 2021 04 22.
Article in English | MEDLINE | ID: covidwho-1174625

ABSTRACT

A discovery program targeting respiratory syncytial virus (RSV) identified C-nucleoside 4 (RSV A2 EC50 = 530 nM) as a phenotypic screening lead targeting the RSV RNA-dependent RNA polymerase (RdRp). Prodrug exploration resulted in the discovery of remdesivir (1, GS-5734) that is >30-fold more potent than 4 against RSV in HEp-2 and NHBE cells. Metabolism studies in vitro confirmed the rapid formation of the active triphosphate metabolite, 1-NTP, and in vivo studies in cynomolgus and African Green monkeys demonstrated a >10-fold higher lung tissue concentration of 1-NTP following molar normalized IV dosing of 1 compared to that of 4. A once daily 10 mg/kg IV administration of 1 in an African Green monkey RSV model demonstrated a >2-log10 reduction in the peak lung viral load. These early data following the discovery of 1 supported its potential as a novel treatment for RSV prior to its development for Ebola and approval for COVID-19 treatment.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Prodrugs/pharmacology , Respiratory Syncytial Virus Infections/drug therapy , Respiratory Syncytial Virus, Human/drug effects , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Caco-2 Cells , Cells, Cultured , Chlorocebus aethiops , Disease Models, Animal , Dogs , Drug Evaluation, Preclinical/methods , Epithelial Cells/virology , Humans , Macaca fascicularis , Male , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Rats, Sprague-Dawley , Respiratory Syncytial Virus Infections/virology , Structure-Activity Relationship , Tissue Distribution , Tubercidin/analogs & derivatives , Tubercidin/chemistry , Viral Load
19.
Antiviral Res ; 188: 105033, 2021 04.
Article in English | MEDLINE | ID: covidwho-1064810

ABSTRACT

Remdesivir (RDV) exhibits potent antiviral activity against SARS-CoV-2 and is currently the only drug approved for the treatment of COVID-19. However, little is currently known about the potential for pre-existing resistance to RDV and the possibility of SARS-CoV-2 genetic diversification that might impact RDV efficacy as the virus continue to spread globally. In this study, >90,000 SARS-CoV-2 sequences from globally circulating clinical isolates, including sequences from recently emerged United Kingdom and South Africa variants, and >300 from mink isolates were analyzed for genetic diversity in the RNA replication complex (nsp7, nsp8, nsp10, nsp12, nsp13, and nsp14) with a focus on the RNA-dependent RNA polymerase (nsp12), the molecular target of RDV. Overall, low genetic variation was observed with only 12 amino acid substitutions present in the entire RNA replication complex in ≥0.5% of analyzed sequences with the highest overall frequency (82.2%) observed for nsp12 P323L that consistently increased over time. Low sequence variation in the RNA replication complex was also observed among the mink isolates. Importantly, the coronavirus Nsp12 mutations previously selected in vitro in the presence of RDV were identified in only 2 isolates (0.002%) within all the analyzed sequences. In addition, among the sequence variants observed in ≥0.5% clinical isolates, including P323L, none were located near the established polymerase active site or sites critical for the RDV mechanism of inhibition. In summary, the low diversity and high genetic stability of the RNA replication complex observed over time and in the recently emerged SARS-CoV-2 variants suggests a minimal global risk of pre-existing SARS-CoV-2 resistance to RDV.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19/virology , Drug Resistance, Viral , Genetic Variation , RNA, Viral , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Virus Replication/genetics , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Amino Acid Substitution , Animals , COVID-19/drug therapy , COVID-19/epidemiology , Evolution, Molecular , Humans , Mink , Models, Molecular , Protein Conformation , SARS-CoV-2/classification , SARS-CoV-2/isolation & purification , Sequence Analysis, DNA , Structure-Activity Relationship , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Whole Genome Sequencing
20.
Antimicrob Agents Chemother ; 65(2)2021 01 20.
Article in English | MEDLINE | ID: covidwho-1044768

ABSTRACT

Remdesivir (RDV, GS-5734), the first FDA-approved antiviral for the treatment of COVID-19, is a single diastereomer monophosphoramidate prodrug of an adenosine analogue. It is intracellularly metabolized into the active triphosphate form, which in turn acts as a potent and selective inhibitor of multiple viral RNA polymerases. RDV has broad-spectrum activity against members of the coronavirus family, such as SARS-CoV-2, SARS-CoV, and MERS-CoV, as well as filoviruses and paramyxoviruses. To assess the potential for off-target toxicity, RDV was evaluated in a set of cellular and biochemical assays. Cytotoxicity was evaluated in a set of relevant human cell lines and primary cells. In addition, RDV was evaluated for mitochondrial toxicity under aerobic and anaerobic metabolic conditions, and for the effects on mitochondrial DNA content, mitochondrial protein synthesis, cellular respiration, and induction of reactive oxygen species. Last, the active 5'-triphosphate metabolite of RDV, GS-443902, was evaluated for potential interaction with human DNA and RNA polymerases. Among all of the human cells tested under 5 to 14 days of continuous exposure, the 50% cytotoxic concentration (CC50) values of RDV ranged from 1.7 to >20 µM, resulting in selectivity indices (SI, CC50/EC50) from >170 to 20,000, with respect to RDV anti-SARS-CoV-2 activity (50% effective concentration [EC50] of 9.9 nM in human airway epithelial cells). Overall, the cellular and biochemical assays demonstrated a low potential for RDV to elicit off-target toxicity, including mitochondria-specific toxicity, consistent with the reported clinical safety profile.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , COVID-19/drug therapy , SARS-CoV-2/drug effects , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/pharmacology , Alanine/chemistry , Alanine/pharmacology , Antiviral Agents/chemistry , COVID-19/virology , Cell Line , Epithelial Cells/drug effects , Humans , Inhibitory Concentration 50 , Mitochondria/drug effects , Primary Cell Culture
SELECTION OF CITATIONS
SEARCH DETAIL