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
The ongoing pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), necessitates strategies to identify prophylactic and therapeutic drug candidates for rapid clinical deployment. Here, we describe a screening pipeline for the discovery of efficacious SARS-CoV-2 inhibitors. We screen a best-in-class drug repurposing library, ReFRAME, against two high-throughput, high-content imaging infection assays: one using HeLa cells expressing SARS-CoV-2 receptor ACE2 and the other using lung epithelial Calu-3 cells. From nearly 12,000 compounds, we identify 49 (in HeLa-ACE2) and 41 (in Calu-3) compounds capable of selectively inhibiting SARS-CoV-2 replication. Notably, most screen hits are cell-line specific, likely due to different virus entry mechanisms or host cell-specific sensitivities to modulators. Among these promising hits, the antivirals nelfinavir and the parent of prodrug MK-4482 possess desirable in vitro activity, pharmacokinetic and human safety profiles, and both reduce SARS-CoV-2 replication in an orthogonal human differentiated primary cell model. Furthermore, MK-4482 effectively blocks SARS-CoV-2 infection in a hamster model. Overall, we identify direct-acting antivirals as the most promising compounds for drug repurposing, additional compounds that may have value in combination therapies, and tool compounds for identification of viral host cell targets.
Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , Drug Repositioning/methods , Pandemics , SARS-CoV-2 , Animals , COVID-19/prevention & control , COVID-19/virology , Cell Line , Cytidine/administration & dosage , Cytidine/analogs & derivatives , Cytidine/pharmacology , Databases, Pharmaceutical , Drug Discovery/methods , Drug Evaluation, Preclinical/methods , HeLa Cells , High-Throughput Screening Assays/methods , Humans , Hydroxylamines/administration & dosage , Hydroxylamines/pharmacology , Mesocricetus , Nelfinavir/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Virus Replication/drug effectsABSTRACT
SARS-CoV-2 has currently precipitated the COVID-19 global health crisis. We developed a medium-throughput drug-screening system and identified a small-molecule library of 34 of 430 protein kinase inhibitors that were capable of inhibiting the SARS-CoV-2 cytopathic effect in human epithelial cells. These drug inhibitors are in various stages of clinical trials. We detected key proteins involved in cellular signaling pathways mTOR-PI3K-AKT, ABL-BCR/MAPK, and DNA-damage response that are critical for SARS-CoV-2 infection. A drug-protein interaction-based secondary screen confirmed compounds, such as the ATR kinase inhibitor berzosertib and torin2 with anti-SARS-CoV-2 activity. Berzosertib exhibited potent antiviral activity against SARS-CoV-2 in multiple cell types and blocked replication at the post-entry step. Berzosertib inhibited replication of SARS-CoV-1 and the Middle East respiratory syndrome coronavirus (MERS-CoV) as well. Our study highlights key promising kinase inhibitors to constrain coronavirus replication as a host-directed therapy in the treatment of COVID-19 and beyond as well as provides an important mechanism of host-pathogen interactions.