RESUMEN
HCV infections are the leading causes for hepatocellular carcinoma and liver transplantation in the United States. Recent advances in drug discovery have identified direct acting antivirals which have significantly improved cure rates in patients. Current efforts are directed towards identification of novel direct acting antiviral targeting different mechanism of actions which could become part of all oral therapies. We recently disclosed the identification of a novel tricyclic indole derived inhibitors of HCV NS5B polymerase that bound to the enzyme close to the active site. In this manuscript we describe further optimization of potency and pharmacokinetics (PK) of these inhibitors to identify compounds in low nM potency against gt-1b. These analogs also demonstrate excellent PK in rats and monkeys when administered as a dimethyl ethyl amino ester prodrug.
Asunto(s)
Ésteres/farmacocinética , Hepacivirus/efectos de los fármacos , Indoles/farmacocinética , Proteínas no Estructurales Virales/antagonistas & inhibidores , Administración Oral , Animales , Descubrimiento de Drogas , Ésteres/química , Haplorrinos , Hepacivirus/enzimología , Humanos , Indoles/química , Profármacos/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
The discovery of lead compound 2e was described. Its covalent binding to HCV NS5B polymerase enzyme was investigated by X-ray analysis. The results of distribution, metabolism and pharmacokinetics were reported. Compound 2e was demonstrated to be potent (replicon GT-1b EC50 = 0.003 µM), highly selective, and safe in in vitro and in vivo assays.
Asunto(s)
Inhibidores Enzimáticos/química , Hepacivirus/enzimología , Indoles/química , Quinolinas/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Cristalografía por Rayos X , Perros , Evaluación Preclínica de Medicamentos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Haplorrinos , Humanos , Indoles/síntesis química , Indoles/farmacocinética , Indoles/farmacología , Masculino , Simulación de Dinámica Molecular , Unión Proteica , Estructura Terciaria de Proteína , Quinolinas/síntesis química , Quinolinas/farmacocinética , Quinolinas/farmacología , Ratas , Ratas Sprague-Dawley , Proteínas no Estructurales Virales/metabolismoRESUMEN
The characterization of HCV genome has identified various vital functional proteins involved in the life cycle of hepatitis C virus. This has resulted in many novel enzymatic targets that are potential for development of therapeutic agents. The HCV RNA dependent RNA polymerase (HCV NS5B) is one such essential enzyme for HCV replication that has been well characterized and studied by various groups to develop novel therapies for hepatitis C. In this paper, we describe our efforts towards the identification and structure-activity relationship (SAR) of novel tricyclic indole derivatives that bind close to the palm site of the NS5B polymerase. X-ray crystal structure of an inhibitor bound to the polymerase is also described.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Hepacivirus/enzimología , Indoles/química , Indoles/farmacología , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Sitios de Unión , Cristalografía por Rayos X , Hepacivirus/química , Hepatitis C/tratamiento farmacológico , Hepatitis C/virología , Humanos , Simulación del Acoplamiento Molecular , ARN Polimerasa Dependiente del ARN/química , ARN Polimerasa Dependiente del ARN/metabolismo , Relación Estructura-ActividadRESUMEN
Development of SAR at the C2 position of indole lead 1, a palm site inhibitor of HCV NS5B polymerase (NS5B IC(50)=0.053µM, replicon EC(50)=4.8µM), is described. Initial screening identified an acyl sulfonamide moiety as an isostere for the C2 carboxylic acid group. Further SAR investigation resulted in identification of acyl sufonamide analog 7q (NS5B IC(50)=0.039µM, replicon EC(50)=0.011µM) with >100-fold improved replicon activity.
Asunto(s)
Antivirales/farmacología , Indoles/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Química Farmacéutica/métodos , Cristalografía por Rayos X/métodos , Diseño de Fármacos , Humanos , Enlace de Hidrógeno , Concentración 50 Inhibidora , Modelos Químicos , Modelos Moleculares , Conformación Molecular , Relación Estructura-Actividad , Sulfonamidas/químicaRESUMEN
SAR development of indole-based palm site inhibitors of HCV NS5B polymerase exemplified by initial indole lead 1 (NS5B IC(50)=0.9 µM, replicon EC(50)>100 µM) is described. Structure-based drug design led to the incorporation of novel heterocyclic moieties at the indole C3-position which formed a bidentate interaction with the protein backbone. SAR development resulted in leads 7q (NS5B IC(50)=0.032 µM, replicon EC(50)=1.4 µM) and 7r (NS5B IC(50)=0.017 µM, replicon EC(50)=0.3 µM) with improved enzyme and replicon activity.
Asunto(s)
Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacología , Compuestos Heterocíclicos/farmacología , Indoles/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Ácidos Carboxílicos , Dominio Catalítico/efectos de los fármacos , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Compuestos Heterocíclicos/síntesis química , Compuestos Heterocíclicos/química , Indoles/síntesis química , Indoles/química , Modelos Moleculares , Estructura Molecular , Estereoisomerismo , Relación Estructura-Actividad , Proteínas no Estructurales Virales/metabolismoRESUMEN
SAR exploration from an initial hit, (S)-N-(2-cyclohexenylethyl)-2-fluoro-6-(2-(1-hydroxy-3-phenylpropan-2-ylamino)-2-oxoethoxy)benzamide (1), identified using our proprietary automated ligand identification system (ALIS),(1) has led to a novel series of selective hepatitis C virus (HCV) NS5B polymerase inhibitors with improved in vitro potency as exemplified by (S)-2-fluoro-6-(2-(1-hydroxy-3-phenylpropan-2-ylamino)-2-oxoethoxy)-N-isopentyl-N-methylbenzamidecarboxamide (41) (IC(50)=0.5 microM). The crystal structure of an analogue (44) was solved and provided rationalization of the SAR of this series, which binds in a distinct manner in the palm domain of NS5B, consistent with biochemical analysis using enzyme mutant variants. These data warrant further lead optimization efforts on this novel series of non-nucleoside inhibitors targeting the HCV polymerase.
Asunto(s)
Benzamidas/química , Benzamidas/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Hepacivirus/enzimología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismo , Antivirales/química , Antivirales/farmacología , Cristalografía , Diseño de Fármacos , Hepatitis C/tratamiento farmacológico , Humanos , Modelos Moleculares , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , ARN Polimerasa Dependiente del ARN/química , ARN Polimerasa Dependiente del ARN/metabolismo , Relación Estructura-Actividad , Proteínas no Estructurales Virales/químicaRESUMEN
Pyridine carboxamide-based inhibitors of the hepatitis C virus (HCV) NS5B polymerase were diversified and optimized to a variety of topologically related scaffolds. In particular, the 2-methyl nicotinic acid scaffold was developed into inhibitors with improved biochemical (IC50-GT1b = 0.014 µM) and cell-based HCV replicon potency (EC50-GT1b = 0.7 µM). Biophysical and biochemical characterization identified this novel series of compounds as palm site binders to HCV polymerase.