Innovative, rapid, high-throughput method for drug repurposing in a pandemic –a case study of SARS-CoV-2 and COVID-19

Abstract

Several efforts to repurpose drugs for COVID-19 treatment have largely either failed to identify a suitable agent or agents identified did not translate to clinical use; either because of demonstrated lack of clinical efficacy in trials, inappropriate dose requirements and probably use of inappropriate pre-clinical laboratory surrogates of effectiveness. In this study, we used an innovative algorithm, that incorporates dissemination and implementation considerations, to identify potential drugs for COVID-19 using iterative computational and wet laboratory methods that highlight inhibition of viral induced cytopathic effect (CPE) as a laboratory surrogate of effectiveness. Erythromycin, pyridoxine, folic acid and retapamulin were found to inhibit SARS-CoV-2 induced CPE in Vero cells at concentrations that are clinically achievable. Additional studies may be required to further characterize the inhibitions of CPE and the possible mechanisms.

Erythromycin, Retapamulin, Pyridoxine, Folic acid and Ivermectin dose dependently inhibit cytopathic effect, Papain-like Protease and MPROof SARS-CoV-2

“…Folic acid also significantly inhibits SARS-CoV-2 Papain like protease and at concentrations and IC 50 that are also achievable at routine therapeutic doses. Indeed, previous molecular docking studies by our group 4 and others 24 suggest Folic acid as potential therapeutic in COVID-19. Wet laboratory studies further suggest that Folic acid inhibits SARS-COV-2 nucleocapsid protein 25 and inhibits cell invasion by SARS-CoV-2 by methylating ACE2 26 .…”

“…This study was conducted as standalone evaluation of the effect of drugs previously identified by in silico screening 4 as potential therapeutics for SARS-CoV-2 infection and COVID-19. Although effect on SARS-CoV-2 induced CPE in Vero cells, SARS-CoV-2 Main protease (M PRO ) and Papain-like protease (PP) were evaluated, these were not considered necessarily linked (mechanistic) because the initial in silico selection was based on predicted activity at 11 independent targets 4 , any combination of which may be related to observed inhibition of CPE. It is interesting that Nirmatrelvir-ritonavir combination(Paxlovid) 17,18 , the current forerunner in COVID-19 therapeutics is an M PRO inhibitor and it is accepted that its efficacy is related to this inhibition 19 .…”

“…Three different doses of each drug were tested for antiviral activity: Erythromycin, Retapamulin, Folic acid and Ivermectin were tested at 5μM, 7.5μM and 10μM, while Pyridoxine was tested at 10 μM, 15 μM and 20 μM, all in three independent replicates. Briefly, we seeded 96-well plates with 6×10 4 cells/mL of Vero E6 (200 μL per well), using Minimum Essential Medium (MEM) with 10% fetal bovine serum (FBS) without antibiotics. Plates were incubated overnight at 37 °C in a 5% CO2 atmosphere.…”

“…SARS-CoV-2 induced cytopathic effect(CPE ) has previously been validated as a surrogate for SARS-CoV-2 infectivity and de-isolation which is non-inferior to PCR 5 . Therefore, in our previous study 4…”

“…SARS-CoV-2 induced cytopathic effect(CPE) has previously been validated as a surrogate for SARS-CoV-2 infectivity and de-isolation which is non-inferior to PCR 5 . Therefore, in our previous study 4 demonstration of inhibition of CPE was considered more cost-effective and a surrogate of clinical efficacy than demonstration of inhibition of viral multiplication alone due to the possibility of threshold effect in viral induced CPE 6 . We also identified Erythromycin, Pyridoxine, Folic acid and Ivermectin as potential drugs to repurpose for COVID-19; with wet laboratory demonstration of inhibition(qualitative assay) of SARS-COV-2 induced CPE in Vero cells and in-silico prediction of inhibition of multiple critical SARS-CoV-2 enzymes 4 .…”