The ongoing pandemic spread of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) demands skillful strategies for novel drug development, drug repurposing and cotreatments, in particular focusing on existing candidates of host-directed antivirals (HDAs). The developmental drug IMU-838, currently being investigated in a phase 2b trial in patients suffering from autoimmune diseases, represents an inhibitor of human dihydroorotate dehydrogenase (DHODH) with a recently proven antiviral activity in vitro and in vivo. Here, we established an analysis system for assessing the antiviral potency of IMU-838 and DHODH-directed back-up drugs in cultured cell-based infection models. By the use of SARS-CoV-2-specific immunofluorescence, Western blot, in-cell ELISA, viral yield reduction and RT-qPCR methods, we demonstrated the following: (i) IMU-838 and back-ups show anti-SARS-CoV-2 activity at several levels of viral replication, i.e., protein production, double-strand RNA synthesis, and release of infectious virus; (ii) antiviral efficacy in Vero cells was demonstrated in a micromolar range (IMU-838 half-maximal effective concentration, EC 50, of 7.6 ± 5.8 µM); (iii) anti-SARS-CoV-2 activity was distinct from cytotoxic effects (half-cytotoxic concentration, CC 50, >100 µM); (iv) the drug in vitro potency was confirmed using several Vero lineages and human cells; (v) combination with remdesivir showed enhanced anti-SARS-CoV-2 activity; (vi) vidofludimus, the active determinant of IMU-838, exerted a broad-spectrum activity against a selection of major human pathogenic viruses. These findings strongly suggest that developmental DHODH inhibitors represent promising candidates for use as anti-SARS-CoV-2 therapeutics.
【저자키워드】 SARS-CoV-2, antiviral therapy, Vidofludimus, host-directed antivirals (HDAs), dihydroorotate dehydrogenase (DHODH) inhibitors, IMU-838, 【초록키워드】 coronavirus, pandemic, Trial, Antiviral, Infection, Remdesivir, drug, in vitro, antiviral activity, anti-SARS-CoV-2, ELISA, Spread, Protein, RT-qPCR, viral replication, Patient, Lineage, antiviral efficacy, immunofluorescence, Autoimmune diseases, in vivo, inhibitor, Combination, Anti-SARS-CoV-2 Activity, Concentration, Analysis, Vero, reduction, acute respiratory syndrome, pathogenic viruses, RNA synthesis, candidate, antiviral potency, Vero Cell, DHODH, half-maximal effective concentration, anti-SARS-CoV-2 therapeutics, investigated, demonstrated, developmental, cytotoxic effect, 【제목키워드】 phase, show, DHODH,