RESUMO
In vitro selection of remdesivir-resistant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed the emergence of a V166L substitution, located outside of the polymerase active site of the Nsp12 protein, after 9 passages of a single lineage. V166L remained the only Nsp12 substitution after 17 passages (10 µM remdesivir), conferring a 2.3-fold increase in 50% effective concentration (EC50). When V166L was introduced into a recombinant SARS-CoV-2 virus, a 1.5-fold increase in EC50 was observed, indicating a high in vitro barrier to remdesivir resistance.
Assuntos
Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/química , Alanina/análogos & derivados , Alanina/metabolismo , Antivirais/química , HumanosRESUMO
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 (1), a novel phosphoramidate prodrug of a 4'-CN-4-aza-7,9-dideazaadenosine C-nucleoside GS-646089 (2) with broad antiviral activity against RSV (EC50 = 3-46 nM), human metapneumovirus (EC50 = 210 nM), human rhinovirus (EC50 = 54-61 nM), and enterovirus (EC50 = 83-90 nM). Prodrug optimization for cellular potency and lung cell metabolism identified 5'-methyl [(S)-hydroxy(phenoxy)phosphoryl]-l-alaninate in combination with 2',3'-diisobutyrate promoieties as being optimal for high levels of intracellular triphosphate formation in vitro and in vivo. 1 demonstrated significant reductions of viral loads in the lower respiratory tract of RSV-infected African green monkeys when administered once daily via intratracheal nebulized aerosol. Together, these findings support additional evaluation of 1 and its analogues as potential therapeutics for pneumo- and picornaviruses.
Assuntos
Antivirais , Picornaviridae , Pró-Fármacos , Infecções por Vírus Respiratório Sincicial , Animais , Antivirais/farmacologia , Antivirais/química , Pró-Fármacos/farmacologia , Pró-Fármacos/química , Pró-Fármacos/síntese química , Chlorocebus aethiops , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Infecções por Vírus Respiratório Sincicial/virologia , Humanos , Picornaviridae/efeitos dos fármacos , Relação Estrutura-Atividade , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Descoberta de Drogas , Nucleosídeos/química , Nucleosídeos/farmacologia , Infecções por Picornaviridae/tratamento farmacológico , Infecções por Picornaviridae/virologiaRESUMO
Remdesivir 1 is an phosphoramidate prodrug that releases the monophosphate of nucleoside GS-441524 (2) into lung cells, thereby forming the bioactive triphosphate 2-NTP. 2-NTP, an analog of ATP, inhibits the SARS-CoV-2 RNA-dependent RNA polymerase replication and transcription of viral RNA. Strong clinical results for 1 have prompted interest in oral approaches to generate 2-NTP. Here, we describe the discovery of a 5'-isobutyryl ester prodrug of 2 (GS-5245, Obeldesivir, 3) that has low cellular cytotoxicity and 3-7-fold improved oral delivery of 2 in monkeys. Prodrug 3 is cleaved presystemically to provide high systemic exposures of 2 that overcome its less efficient metabolism to 2-NTP, leading to strong SARS-CoV-2 antiviral efficacy in an African green monkey infection model. Exposure-based SARS-CoV-2 efficacy relationships resulted in an estimated clinical dose of 350-400 mg twice daily. Importantly, all SARS-CoV-2 variants remain susceptible to 2, which supports development of 3 as a promising COVID-19 treatment.