ABSTRACT
COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. PF-00835231, a 3CL protease inhibitor, has exhibited potent in vitro antiviral activity against SARS-CoV-2 as a single agent. Here we report, the design and characterization of a phosphate prodrug PF-07304814 to enable the delivery and projected sustained systemic exposure in human of PF-00835231 to inhibit coronavirus family 3CL protease activity with selectivity over human host protease targets. Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment.
Subject(s)
COVID-19 Drug Treatment , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Protease Inhibitors/administration & dosage , Indoles/administration & dosage , Leucine/administration & dosage , Pyrrolidinones/administration & dosage , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/adverse effects , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacokinetics , Alanine/administration & dosage , Alanine/adverse effects , Alanine/analogs & derivatives , Alanine/pharmacokinetics , Animals , COVID-19/virology , Chlorocebus aethiops , Coronavirus 229E, Human/drug effects , Coronavirus 229E, Human/enzymology , Coronavirus Protease Inhibitors/adverse effects , Coronavirus Protease Inhibitors/pharmacokinetics , Disease Models, Animal , Drug Design , Drug Synergism , Drug Therapy, Combination , HeLa Cells , Humans , Indoles/adverse effects , Indoles/pharmacokinetics , Infusions, Intravenous , Leucine/adverse effects , Leucine/pharmacokinetics , Mice , Pyrrolidinones/adverse effects , Pyrrolidinones/pharmacokinetics , Severe acute respiratory syndrome-related coronavirus/drug effects , Severe acute respiratory syndrome-related coronavirus/enzymology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Vero CellsABSTRACT
We report the design and synthesis of a series of new 5-chloropyridinyl esters of salicylic acid, ibuprofen, indomethacin, and related aromatic carboxylic acids for evaluation against SARS-CoV-2 3CL protease enzyme. These ester derivatives were synthesized using EDC in the presence of DMAP to provide various esters in good to excellent yields. Compounds are stable and purified by silica gel chromatography and characterized using 1H-NMR, 13C-NMR, and mass spectral analysis. These synthetic derivatives were evaluated in our in vitro SARS-CoV-2 3CLpro inhibition assay using authentic SARS-CoV-2 3CLpro enzyme. Compounds were also evaluated in our in vitro antiviral assay using quantitative VeroE6 cell-based assay with RNAqPCR. A number of compounds exhibited potent SARS-CoV-2 3CLpro inhibitory activity and antiviral activity. Compound 9a was the most potent inhibitor, with an enzyme IC50 value of 160 nM. Compound 13b exhibited an enzyme IC50 value of 4.9 µM. However, it exhibited a potent antiviral EC50 value of 24 µM in VeroE6 cells. Remdesivir, an RdRp inhibitor, exhibited an antiviral EC50 value of 2.4 µM in the same assay. We assessed the mode of inhibition using mass spectral analysis which suggested the formation of a covalent bond with the enzyme. To obtain molecular insight, we have created a model of compound 9a bound to SARS-CoV-2 3CLpro in the active site.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , COVID-19 Drug Treatment , Coronavirus 3C Proteases/antagonists & inhibitors , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Chlorocebus aethiops , Coronavirus 3C Proteases/metabolism , Esters/chemistry , Esters/pharmacology , Halogenation , Humans , Ibuprofen/analogs & derivatives , Ibuprofen/pharmacology , Indomethacin/analogs & derivatives , Indomethacin/pharmacology , Molecular Docking Simulation , Pyridines/chemistry , Pyridines/pharmacology , SARS-CoV-2/metabolism , Salicylic Acid/chemistry , Salicylic Acid/pharmacology , Vero CellsABSTRACT
Here, we report the synthesis, structure-activity relationship studies, enzyme inhibition, antiviral activity, and X-ray crystallographic studies of 5-chloropyridinyl indole carboxylate derivatives as a potent class of SARS-CoV-2 chymotrypsin-like protease inhibitors. Compound 1 exhibited a SARS-CoV-2 3CLpro inhibitory IC50 value of 250 nM and an antiviral EC50 value of 2.8 µM in VeroE6 cells. Remdesivir, an RNA-dependent RNA polymerase inhibitor, showed an antiviral EC50 value of 1.2 µM in the same assay. Compound 1 showed comparable antiviral activity with remdesivir in immunocytochemistry assays. Compound 7d with an N-allyl derivative showed the most potent enzyme inhibitory IC50 value of 73 nM. To obtain molecular insight into the binding properties of these molecules, X-ray crystal structures of compounds 2, 7b, and 9d-bound to SARS-CoV 3CLpro were determined, and their binding properties were compared.
Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Indoles/chemistry , Protease Inhibitors/chemistry , SARS-CoV-2/enzymology , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/metabolism , Alanine/analogs & derivatives , Alanine/chemistry , Alanine/metabolism , Animals , Binding Sites , COVID-19/pathology , COVID-19/virology , Chlorocebus aethiops , Coronavirus 3C Proteases/metabolism , Crystallography, X-Ray , Humans , Indoles/chemical synthesis , Indoles/metabolism , Molecular Dynamics Simulation , Protease Inhibitors/chemical synthesis , Protease Inhibitors/metabolism , Pyridines/chemistry , SARS-CoV-2/isolation & purification , Structure-Activity Relationship , Vero CellsABSTRACT
Except remdesivir, no specific antivirals for SARS-CoV-2 infection are currently available. Here, we characterize two small-molecule-compounds, named GRL-1720 and 5h, containing an indoline and indole moiety, respectively, which target the SARS-CoV-2 main protease (Mpro). We use VeroE6 cell-based assays with RNA-qPCR, cytopathic assays, and immunocytochemistry and show both compounds to block the infectivity of SARS-CoV-2 with EC50 values of 15 ± 4 and 4.2 ± 0.7 µM for GRL-1720 and 5h, respectively. Remdesivir permitted viral breakthrough at high concentrations; however, compound 5h completely blocks SARS-CoV-2 infection in vitro without viral breakthrough or detectable cytotoxicity. Combination of 5h and remdesivir exhibits synergism against SARS-CoV-2. Additional X-ray structural analysis show that 5h forms a covalent bond with Mpro and makes polar interactions with multiple active site amino acid residues. The present data suggest that 5h might serve as a lead Mpro inhibitor for the development of therapeutics for SARS-CoV-2 infection.
Subject(s)
COVID-19 Drug Treatment , Coronavirus Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Viral Proteases/drug effects , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Alanine/analogs & derivatives , Alanine/pharmacology , Animals , Antiviral Agents/pharmacology , Cell Line , Chlorocebus aethiops , Humans , Indoles/pharmacology , Pyridines/pharmacology , Vero Cells , Viral Proteases/metabolismABSTRACT
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 has triggered an ongoing global pandemic of the severe pneumonia-like disease coronavirus disease 2019 (COVID-19)1. The development of a vaccine is likely to take at least 12-18 months, and the typical timeline for approval of a new antiviral therapeutic agent can exceed 10 years. Thus, repurposing of known drugs could substantially accelerate the deployment of new therapies for COVID-19. Here we profiled a library of drugs encompassing approximately 12,000 clinical-stage or Food and Drug Administration (FDA)-approved small molecules to identify candidate therapeutic drugs for COVID-19. We report the identification of 100 molecules that inhibit viral replication of SARS-CoV-2, including 21 drugs that exhibit dose-response relationships. Of these, thirteen were found to harbour effective concentrations commensurate with probable achievable therapeutic doses in patients, including the PIKfyve kinase inhibitor apilimod2-4 and the cysteine protease inhibitors MDL-28170, Z LVG CHN2, VBY-825 and ONO 5334. Notably, MDL-28170, ONO 5334 and apilimod were found to antagonize viral replication in human pneumocyte-like cells derived from induced pluripotent stem cells, and apilimod also demonstrated antiviral efficacy in a primary human lung explant model. Since most of the molecules identified in this study have already advanced into the clinic, their known pharmacological and human safety profiles will enable accelerated preclinical and clinical evaluation of these drugs for the treatment of COVID-19.