RESUMO
Described herein is the development of a potent non-nucleoside, small molecule inhibitor of genotype 1 HCV NS5B Polymerase. A 23 µM inhibitor that was active against HCV polymerase was further elaborated into a potent single-digit nanomolar inhibitor of HCV NS5B polymerase by additional manipulation of the R and R1 substituents. Subsequent modifications to improve physical properties were made in an attempt to achieve an acceptable pharmacokinetic profile.
Assuntos
Antivirais/síntese química , Hepacivirus/enzimologia , Uracila/análogos & derivados , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacocinética , Meia-Vida , Hepacivirus/fisiologia , Ratos , Relação Estrutura-Atividade , Uracila/síntese química , Uracila/farmacocinética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacosRESUMO
Aryl dihydrouracil derivatives were identified from high throughput screening as potent inhibitors of HCV NS5B polymerase. The aryl dihydrouracil derivatives were shown to be non-competitive with respect to template RNA and elongation nucleotide substrates. They demonstrated genotype 1 specific activity towards HCV NS5B polymerases. Structure activity relationships and genotype specific activities of aryl dihydrouracil derivatives suggested that they bind to the palm initiation nucleotide pocket, a hypothesis which was confirmed by studies with polymerases containing mutations in various inhibitor binding sites. Therefore, aryl dihydrouracil derivatives represent a novel class of palm initiation site inhibitors of HCV NS5B polymerase.
Assuntos
Inibidores de Proteases/química , Uracila/análogos & derivados , Proteínas não Estruturais Virais/antagonistas & inibidores , Substituição de Aminoácidos , Genótipo , Hepacivirus/efeitos dos fármacos , Hepacivirus/enzimologia , Cinética , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacologia , Relação Estrutura-Atividade , Sítio de Iniciação de Transcrição , Uracila/síntese química , Uracila/química , Uracila/farmacologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismoRESUMO
Hepatitis C virus (HCV) replicon-based shuttle vectors that permit phenotypes of NS5B polymerase genes from a large number of patient isolates to be rapidly assessed when transiently expressed in cultured cells were designed. When used to test responses to an inhibitor of HCV RNA-dependent RNA polymerase, IC(50) values for inhibition covered a several hundred-fold range among 47 patient samples tested. This observation highlights the variability that can be found by testing isolates derived from HCV-infected subjects. Partial suppression with a polymerase inhibitor of the most sensitive species permitted detection of minor quasispecies that were 7-200-fold more resistant than the bulk population in approximately half of the samples. Sequence analysis showed a wide range of amino acid changes not detected by conventional selection methods using laboratory-derived strains. This approach provides a means to assess variation in antiviral efficacy, and to predict possible responses in a clinical setting.