GS-441524

GS-441524 is the predominant metabolite of remdesivir in blood and is the nucleoside of the prodrug remdesivir. It is phosphorylated to the active triphosphate metabolite which incorporates into RNA. It shows broad spectrum activity in cell based assays against HCV, YFV, DENV-2, Influenza A, Parainfluenza 3 and SARS-CoV viruses with EC₅₀ values ranging from 1.7 μM-27.9 μM. It inhibits SARS-CoV and MERS-CoV infected human airway epithelial cell cultures with EC₅₀ values of 0.18 μM and 0.86 μM respectively. GS-441524 is suggested for the treatment of COVID-19 due to lower toxicity and simpler synthesis when compared to remdesivir.