The Preclinical Inhibitor GS441524 in Combination with GC376 Efficaciously Inhibited the Proliferation of SARS-CoV-2 in the Mouse Respiratory Tract

Abstract

The unprecedented coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a serious threat to global public health. Development of effective therapies against SARS-CoV-2 is urgently needed. Here, we evaluated the antiviral activity of a remdesivir parent nucleotide analog, GS441524, which targets the coronavirus RNA-dependent RNA polymerase enzyme, and a feline coronavirus prodrug, GC376, which targets its main protease, using a mouse-adapted SARS-CoV-2 infected mouse model. Our results showed that GS441524 effectively blocked the proliferation of SARS-CoV-2 in the mouse upper and lower respiratory tracts via combined intranasal (i.n.) and intramuscular (i.m.) treatment. However, the ability of high-dose GC376 (i.m. or i.n. and i.m.) was weaker than GS441524. Notably, low-dose combined application of GS441524 with GC376 could effectively protect mice against SARS-CoV-2 infection via i.n. or i.n. and i.m. treatment. Moreover, we found that the pharmacokinetic properties of GS441524 is better than GC376, and combined application of GC376 and GS441524 had a synergistic effect. Our findings support the further evaluation of the combined application of GC376 and GS441524 in future clinical studies.ImportanceSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has seriously threatened global public health and economic development. Currently, effective therapies to treat COVID-19 are urgently needed. In this study, we assessed the efficacy of the preclinical inhibitors GC376 and GS441524 using a mouse-adapted SARS-CoV-2 infected mouse model for the first time. Our results showed that low-dose combined application of GC376 and GS441524 could effectively protect mice from HRB26M infection in the upper and lower respiratory tracts. Hence, the combined application should be developed and considered for future clinic practice.

A robust SARS-CoV-2 replication model in primary human epithelial cells at the air liquid interface to assess antiviral agents

“…Four nucleoside analogues that are known inhibitors of SARS-CoV-2 replication were selected as reference for studies in HAEC cultures. These included remdesivir, GS-441524 ( Li et al, 2021 ; Pruijssers et al, 2020 ; Shi et al, 2020 ; Xie et al, 2020 ; Zandi et al, 2020 ) (the parent nucleoside of remdesivir), EIDD-1931 ( Zandi et al, 2020 ; Good et al, 2021 ; Sheahan et al, 2020 ) (the parent nucleoside of molnupiravir) and AT-511 ( Good et al, 2021 ) [a guanosine nucleotide analogue with activity against hepatitis C virus (HCV)]. To select a suitable concentration range of these molecules, we first explored their effect in VeroE6 and Huh7 cell lines.…”

“…These results are in agreement with an earlier study ( Pruijssers et al, 2020 ), where the virus replication was monitored for 3 days. We demonstrated that the parent nucleoside GS-441524 ( Li et al, 2021 ; Pruijssers et al, 2020 ; Shi et al, 2020 ; Xie et al, 2020 ; Zandi et al, 2020 ) at 2 μM can also “sterilize” HAEC cultures from SARS-CoV2 as no rebound of the virus was noted several days after removal of the molecule. At 1 μM GS-441524, an intermediate antiviral potency was observed, but significant antiviral activity was not observed at 0.4 μM in the HAEC cultures.…”

Considerations for the discovery and development of 3-chymotrypsin-like cysteine protease inhibitors targeting SARS-CoV-2 infection

“…GC-376 administered subcutaneously twice daily resulted in partial to full recovery in laboratory and client-owned cats infected with feline coronavirus [ 11 , 14 ]. In a mouse model of SARS-CoV-2 infection, intranasal and combined intranasal + intramuscular treatment with GC-376 only achieved marginal reduction in viral load [ 33 ]. The antiviral effect of GC-376 was improved when combined with GS441524, the parent nucleoside of the remdesivir prodrug.…”

ALG-097111, a potent and selective SARS-CoV-2 3-chymotrypsin-like cysteine protease inhibitor exhibits in vivo efficacy in a Syrian Hamster model

“…Cathepsin L is involved in the entry of SARS-CoV-2 into host cells and therefore contributes to non-selective 3CLpro inhibitor potency in commonly used cell lines. GC-376, a broad spectrum inhibitor of 3C, 3C-like proteases and cathepsin L, failed to show a clear antiviral effect in monotherapy in a mouse model of SARS-CoV-2 infection [ 10 ]. In another study modest antiviral activity was observed in the K18-hACE2 SARS-CoV2 infection mouse model [ 11 ].…”