GS-443902 trisodium (GS-441524 triphosphate trisodium) is a potent viral RNA-dependent RNA-polymerases (RdRp) inhibitor with IC50s of 1.1 µM, 5 µM for RSV RdRp and HCV RdRp, respectively. GS-443902 trisodium is the active triphosphate metabolite of Remdesivir (GS-5734)[1][2].