A comparative analysis of SARS-CoV-2 antivirals in human airway models characterizes 3CL^proinhibitor PF-00835231 as a potential new treatment for COVID-19

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of Coronavirus Disease 2019 (COVID-19), a pandemic that has claimed over 700,000 human lives. The only SARS-CoV-2 antiviral, for emergency use, is remdesivir, targeting the viral polymerase complex. PF-00835231 is a pre-clinical lead compound with an alternate target, the main SARS-CoV-2 protease 3CLpro (Mpro). Here, we perform a comparative analysis of PF-00835231 and remdesivir in A549+ACE2 cells, using isolates of two major SARS-CoV-2 clades. PF-00835231 is antiviral for both clades, and, in this assay, statistically more potent than remdesivir. A time-of-drug-addition approach delineates the timing of early SARS-CoV-2 life cycle steps and validates PF-00835231’s time of action. Both PF-00835231 and remdesivir potently inhibit SARS-CoV-2 in human polarized airway epithelial cultures. Thus, our study provides in vitro evidence for the potential of PF-00835231 as an effective antiviral for SARS-CoV-2, addresses concerns from non-human in vitro models, and supports further studies with this compound.

Discovery of a Novel Inhibitor of Coronavirus 3CL Protease for the Potential Treatment of COVID-19

“…Consistent with many viral protease inhibitors 21 , there was a steep response to increasing doses of PF-00835231, with a ~2-3 fold difference between EC 50 and EC 90 in both cell types (EC 90 = 0.48μM in VeroE6-enACE2 cells and EC 90 = 1.6μM in VeroE6-EGFP cells in the presence of the P-gp inhibitor). As expected, when lung cell lines were tested for antiviral potency in the presence and absence of P-gp inhibitor (A549-ACE2 22 and MRC5), no statistical difference in antiviral potency was observed (Fig. 2A).…”

“…2A). Additionally, antiviral activities in both VeroE6 cell lines with 2μM P-gp inhibitor are similar to those observed in more physiologically relevant human lung cell culture systems, including A549-ACE2 and polarized human airway epithelial cells 22 , where P-gp expression is lower. These data support the potential for single agent antiviral activity.…”

“…PF-07304814 is a phosphate prodrug that is rapidly converted in vivo to the active moiety, PF-00835231, which exhibits high selectivity over human proteases and acts as a broad-spectrum coronavirus 3CL protease inhibitor. Robust antiviral activity was demonstrated in a range of cellular in vitro assays in keeping with SARS-COV-2 human airway epithelial data (23) suggesting a Ceff value of ~0.5µM. The predicted human pharmacokinetics of PF-07304814 provide the ability to achieve systemic unbound concentrations of 0.5µM (EC90) of PF-00835231 by delivering 500mg as a continuous infusion over 24 hours with infusion volumes of less than 0.25L.…”

Inhibitory Potential Of Black Seed (Nigella Sativa L.) Bioactive Compounds Towards Main Protease Of SARS-CoV-2 : In Silico Study

“…there is no folding and proper assembly into the active polymerase complex. Therefore, inhibition of Mpro activity could terminate the virus life cycle prior to transcription or replication, making Mpro a key enzyme of SARS-CoV-2 viral infection (de Vries et al, 2020;Ullrich & Nitsche, 2020). This indicates DOI: http://dx.doi.org/10.14203/ann.bogor.2020.v24.n2.81-94 that the enzyme is a potential drug target for SARS-CoV-2.…”

Repurposing Approved Drugs for Guiding COVID-19 Prophylaxis: A Systematic Review

“…PF-00835231 is a ketone-based designed for inhibiting the SARS-CoV-1 virus (Yen et al, 2004). Recently, two studies revealed this drug as a potent inhibitor which were tested by FRET assay and for antiviral activity in Vero E6 cells with an IC50 0.00027 ± 0.0001 μM for 3C-like protease (Hoffman et al, 2020), as well as demonstrated to be statistically more potent than remdesivir in assays with infected SARS-CoV-2 A549 +ACE2 cells with an EC 50 of 0.221 μM at 24 h, and 0.158 μM at 48 h without detectable cytotoxicity (de Vries et al, 2020).…”