Discovery of GS-7682, a Novel 4'-Cyano-Modified -Nucleoside Prodrug with Broad Activity against Pneumo- and Picornaviruses and Efficacy in RSV-Infected African Green Monkeys.

Acute respiratory viral infections, such as pneumovirus and respiratory picornavirus infections, exacerbate disease in COPD and asthma patients. A research program targeting respiratory syncytial virus (RSV) led to the discovery of GS-7682 (), a novel phosphoramidate prodrug of a 4'-CN-4-aza-7,9-dideazaadenosine -nucleoside GS-646089 () with broad antiviral activity against RSV (EC = 3-46 nM), human metapneumovirus (EC = 210 nM), human rhinovirus (EC = 54-61 nM), and enterovirus (EC = 83-90 nM). Prodrug optimization for cellular potency and lung cell metabolism identified 5'-methyl [()-hydroxy(phenoxy)phosphoryl]-l-alaninate in combination with 2',3'-diisobutyrate promoieties as being optimal for high levels of intracellular triphosphate formation and .

The oral nucleoside prodrug GS-5245 is efficacious against SARS-CoV-2 and other endemic, epidemic, and enzootic coronaviruses.

Despite the wide availability of several safe and effective vaccines that prevent severe COVID-19, the persistent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that can evade vaccine-elicited immunity remains a global health concern. In addition, the emergence of SARS-CoV-2 VOCs that can evade therapeutic monoclonal antibodies underscores the need for additional, variant-resistant treatment strategies. Here, we characterize the antiviral activity of GS-5245, obeldesivir (ODV), an oral prodrug of the parent nucleoside GS-441524, which targets the highly conserved viral RNA-dependent RNA polymerase (RdRp).

Discovery of GS-5245 (Obeldesivir), an Oral Prodrug of Nucleoside GS-441524 That Exhibits Antiviral Efficacy in SARS-CoV-2-Infected African Green Monkeys.

Remdesivir is an phosphoramidate prodrug that releases the monophosphate of nucleoside GS-441524 () into lung cells, thereby forming the bioactive triphosphate . , an analog of ATP, inhibits the SARS-CoV-2 RNA-dependent RNA polymerase replication and transcription of viral RNA. Strong clinical results for have prompted interest in oral approaches to generate .

Efficacy of the oral nucleoside prodrug GS-5245 (Obeldesivir) against SARS-CoV-2 and coronaviruses with pandemic potential.

Despite the wide availability of several safe and effective vaccines that can prevent severe COVID-19 disease, the emergence of SARS-CoV-2 variants of concern (VOC) that can partially evade vaccine immunity remains a global health concern. In addition, the emergence of highly mutated and neutralization-resistant SARS-CoV-2 VOCs such as BA.1 and BA.