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. 2021 Mar 18;65(4):e02479-20. doi: 10.1128/AAC.02479-20

TABLE 1.

In vitro activity of AT-511 and other oral antiviral drugs against various human coronavirusesa

Virus (genus) Cell line Compound CPE assay
VYR assay EC90 (μM [n]) Selectivity index (CC50/EC50)
EC50 (μM [n]) CC50 (μM)
HCoV-229E (Alphacoronavirus) BHK-21 AT-511 1.8 ± 0.3 [2] >100 ND >55
BHK-21 Sofosbuvir >100 >100 ND ND
Huh-7 AT-511 1.7 ± 0.1 [2] >86 1.2 ± 0.1 [2] >50
HCoV-OC43 (Betacoronavirus) Huh-7 AT-511 NDb >86 0.5 >170c
RD AT-511 2.8 >86 2.2 >30
MERS-CoV (Betacoronavirus) Huh-7 AT-511 26 ± 15 [2] >86 37 ± 28 [2] >3.3
SARS-CoV (Betacoronavirus) Huh-7 AT-511 NDb >86 0.34 >250c
SARS-CoV-2 (Betacoronavirus) HAE AT-511 NDb >86d 0.47 ± 0.12 [5] >160c
HAE Molnupiravir NDb >19d 2.8 ± 1.0 [3] >4.9c
a

The activity of AT-511 and other antiviral compounds was measured in cells infected with different coronaviruses, using the cytopathic effect (neutral red dye) assay and/or the virus yield reduction (VYR) assay as described in Materials and Methods, to determine the effective concentration required to achieve 50% inhibition (EC50) of the virus-induced cytopathic effect (CPE), the concentration to reduce virus yield by 1 log10 (EC90), and the cytotoxic concentration of the drug to cause death to 50% of viable cells without virus (CC50). Values represent results from single or multiple (mean ± SD [n]) experiments.

b

Not determined because no cytopathic effect was produced by this virus in this cell line.

c

CC50/EC90, since EC50 could not be determined by measuring CPE in the neutral red assay.

d

Cytotoxicity assessed by visual inspection of cell monolayers.

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