ABSTRACT
Herein we describe the discovery of IDX21437 35b, a novel RPd-aminoacid-based phosphoramidate prodrug of 2'-α-chloro-2'-ß-C-methyluridine monophosphate. Its corresponding triphosphate 6 is a potent inhibitor of the HCV NS5B RNA-dependent RNA polymerase (RdRp). Despite showing very weak activity in the in vitro Huh-7 cell based HCV replicon assay, 35b demonstrated high levels of active triphosphate 6 in mouse liver and human hepatocytes. A biochemical study revealed that the metabolism of 35b was mainly attributed to carboxyesterase 1 (CES1), an enzyme which is underexpressed in HCV Huh-7-derived replicon cells. Furthermore, due to its metabolic activation, 35b was efficiently processed in liver cells compared to other cell types, including human cardiomyocytes. The selected RP diastereoisomeric configuration of 35b was assigned by X-ray structural determination. 35b is currently in Phase II clinical trials for the treatment of HCV infection.
Subject(s)
Antiviral Agents/pharmacology , DNA-Directed RNA Polymerases/antagonists & inhibitors , Drug Discovery , Enzyme Inhibitors/pharmacology , Hepacivirus/drug effects , Uridine Monophosphate/analogs & derivatives , Uridine/pharmacology , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , DNA-Directed RNA Polymerases/metabolism , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Hepacivirus/enzymology , Hepatocytes/drug effects , Hepatocytes/virology , Humans , Liver/drug effects , Liver/virology , Mice , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship , Uridine/chemical synthesis , Uridine/chemistry , Uridine Monophosphate/chemical synthesis , Uridine Monophosphate/chemistry , Uridine Monophosphate/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolismABSTRACT
Hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase (RdRp) plays a central role in virus replication. NS5B has no functional equivalent in mammalian cells, and as a consequence is an attractive target for selective inhibition. This paper describes the discovery of a novel family of HCV NS5B non-nucleoside inhibitors inspired by the bioisosterism between sulfonamide and phosphonamide. Systematic structural optimization in this new series led to the identification of IDX375, a potent non-nucleoside inhibitor that is selective for genotypes 1a and 1b. The structure and binding domain of IDX375 were confirmed by X-ray co-crystalisation study.
Subject(s)
Antiviral Agents/chemistry , Hepacivirus/enzymology , Lactams/chemistry , Organophosphorus Compounds/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Allosteric Regulation , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Binding Sites , Crystallography, X-Ray , Genotype , Half-Life , Haplorhini , Hepacivirus/genetics , Hepacivirus/physiology , Humans , Lactams/pharmacology , Mice , Molecular Dynamics Simulation , Organophosphorus Compounds/pharmacology , Protein Structure, Tertiary , Rats , Structure-Activity Relationship , Sulfonamides/chemistry , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effectsABSTRACT
Here, we describe the design, synthesis, biological evaluation, and identification of a clinical candidate non-nucleoside reverse transcriptase inhibitors (NNRTIs) with a novel aryl-phospho-indole (APhI) scaffold. NNRTIs are recommended components of highly active antiretroviral therapy (HAART) for the treatment of HIV-1. Since a major problem associated with NNRTI treatment is the emergence of drug resistant virus, this work focused on optimization of the APhI against clinically relevant HIV-1 Y181C and K103N mutants and the Y181C/K103N double mutant. Optimization of the phosphinate aryl substituent led to the discovery of the 3-Me,5-acrylonitrile-phenyl analogue RP-13s (IDX899) having an EC50 of 11 nM against the Y181C/K103N double mutant.
Subject(s)
Anti-HIV Agents/pharmacology , Drug Discovery , HIV Reverse Transcriptase/antagonists & inhibitors , HIV-1/drug effects , HIV-1/enzymology , Indoles/pharmacology , Phosphinic Acids/pharmacology , Reverse Transcriptase Inhibitors/pharmacology , Animals , Anti-HIV Agents/chemical synthesis , Anti-HIV Agents/chemistry , Cell Line , Crystallography, X-Ray , Dogs , Dose-Response Relationship, Drug , HIV Reverse Transcriptase/metabolism , Hepatocytes/chemistry , Hepatocytes/metabolism , Humans , Indoles/chemical synthesis , Indoles/chemistry , Macaca fascicularis , Male , Models, Molecular , Molecular Structure , Phosphinic Acids/chemical synthesis , Phosphinic Acids/chemistry , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Inhibitors/chemical synthesis , Reverse Transcriptase Inhibitors/chemistry , Structure-Activity RelationshipABSTRACT
A novel series of 3-aryl-phospho-indole (API) non-nucleoside reverse transcriptase inhibitors of HIV-1 was developed. Chemical variation in the phosphorus linker led to the discovery of 3-phenyl-methyl-phosphinate-2-carboxamide 14, which possessed excellent potency against wild-type HIV-1 as well as viruses bearing K103N and Y181C single mutants in the reverse transcriptase gene. Chiral separation of the enantiomers showed that only R enantiomer retained the activity. The pharmacokinetic, solubility, and metabolic properties of 14 were assessed.
