ABSTRACT
Direct-acting antiviral inhibitors have revolutionized the treatment of hepatitis C virus (HCV) infected patients. Herein is described the discovery of velpatasvir (VEL, GS-5816), a potent pan-genotypic HCV NS5A inhibitor that is a component of the only approved pan-genotypic single-tablet regimens (STRs) for the cure of HCV infection. VEL combined with sofosbuvir (SOF) is Epclusa®, an STR with 98% cure-rates for genotype 1-6 HCV infected patients. Addition of the pan-genotypic HCV NS3/4A protease inhibitor voxilaprevir to SOF/VEL is the STR Vosevi®, which affords 97% cure-rates for genotype 1-6 HCV patients who have previously failed another treatment regimen.
Subject(s)
Antiviral Agents/pharmacology , Carbamates/pharmacology , Drug Discovery , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/pharmacology , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Carbamates/chemical synthesis , Carbamates/chemistry , Dose-Response Relationship, Drug , Drug Combinations , Genotype , Hepacivirus/genetics , Heterocyclic Compounds, 4 or More Rings/chemical synthesis , Heterocyclic Compounds, 4 or More Rings/chemistry , Humans , Macrocyclic Compounds/chemistry , Microbial Sensitivity Tests , Molecular Structure , Protease Inhibitors/chemical synthesis , Protease Inhibitors/chemistry , Sofosbuvir/chemistry , Structure-Activity Relationship , Sulfonamides/chemistry , Tablets/chemistry , Tablets/pharmacology , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolismABSTRACT
Treatment of hepatitis C virus (HCV) infection has been historically challenging due the high viral genetic complexity wherein there are eight distinct genotypes and at least 86 viral subtypes. While HCV NS3/4A protease inhibitors are an established treatment option for genotype 1 infection, limited coverage of genotypes 2 and/or 3 combined with serum alanine transaminase (ALT) elevations for some compounds has limited the broad utility of this therapeutic class. Our discovery efforts were focused on identifying an NS3/4A protease inhibitor with pan-genotypic antiviral activity, improved coverage of resistance associated substitutions, and a decreased risk of hepatotoxicity. Towards this goal, distinct interactions with the conserved catalytic triad of the NS3/4A protease were identified that improved genotype 3 antiviral activity. We further discovered that protein adduct formation strongly correlated with clinical ALT elevation for this therapeutic class. Improving metabolic stability and decreasing protein adduct formation through structural modifications ultimately resulted in voxilaprevir. Voxilaprevir, in combination with sofosbuvir and velpatasvir, has demonstrated pan-genotypic antiviral clinical activity. Furthermore, hepatotoxicity was not observed in Phase 3 clinical trials with voxilaprevir, consistent with our design strategy. Vosevi® (sofosbuvir, velpatasvir, and voxilaprevir) is now an approved pan-genotypic treatment option for the most difficult-to-cure individuals who have previously failed direct acting antiviral therapy.
Subject(s)
Antiviral Agents/pharmacology , Carbamates/chemistry , Drug Discovery , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/chemistry , Macrocyclic Compounds/chemistry , Macrocyclic Compounds/pharmacology , Protease Inhibitors/pharmacology , Sofosbuvir/chemistry , Sulfonamides/chemistry , Sulfonamides/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Aminoisobutyric Acids , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Cyclopropanes , Dose-Response Relationship, Drug , Drug Combinations , Hepacivirus/genetics , Humans , Lactams, Macrocyclic , Leucine/analogs & derivatives , Macrocyclic Compounds/chemical synthesis , Microbial Sensitivity Tests , Molecular Structure , Proline/analogs & derivatives , Protease Inhibitors/chemical synthesis , Protease Inhibitors/chemistry , Quinoxalines , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolismABSTRACT
A novel series of non-nucleoside small molecules containing a tricyclic dihydropyridinone structural motif was identified as potent HCV NS5B polymerase inhibitors. Driven by structure-based design and building on our previous efforts in related series of molecules, we undertook extensive SAR studies, in which we identified a number of metabolically stable and very potent compounds in genotype 1a and 1b replicon assays. This work culminated in the discovery of several inhibitors, which combined potent in vitro antiviral activity against both 1a and 1b genotypes, metabolic stability, good oral bioavailability, and high C(12) (PO)/EC(50) ratios.
Subject(s)
Biological Availability , Drug Design , Structure-Activity Relationship , Antiviral Agents/pharmacokinetics , Chemistry, Pharmaceutical , Crystallography, X-Ray , Drug Evaluation, Preclinical , Genotype , Hepacivirus/drug effects , Hepatitis C , Molecular Structure , RNA-Dependent RNA Polymerase , Viral Nonstructural Proteins/antagonists & inhibitorsABSTRACT
The discovery of 5,5'- and 6,6'-dialkyl-5,6-dihydro-1H-pyridin-2-ones as potent inhibitors of the HCV RNA-dependent RNA polymerase (NS5B) is described. Several of these agents also display potent antiviral activity in cell culture experiments (EC50 <0.10 microM). In vitro DMPK data for selected compounds as well as crystal structures of representative inhibitors complexed with the NS5B protein are also disclosed.
Subject(s)
Antiviral Agents/chemistry , Enzyme Inhibitors/chemistry , Hepacivirus/enzymology , Pyridones/chemistry , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , Binding Sites , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Humans , Macaca fascicularis , Microsomes, Liver/metabolism , Pyridones/chemical synthesis , Pyridones/pharmacology , RNA-Dependent RNA Polymerase/metabolism , Structure-Activity RelationshipABSTRACT
5,6-Dihydro-1H-pyridin-2-one analogs were discovered as a novel class of inhibitors of genotype 1 HCV NS5B polymerase. Among these, compound 4ad displayed potent inhibitory activities in biochemical and replicon assays (IC(50) (1b)<10nM; IC(50) (1a)<25nM, EC(50) (1b)=16nM), good in vitro DMPK properties, as well as moderate oral bioavailability in monkeys (F=24%).
Subject(s)
DNA-Directed RNA Polymerases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Pyridones/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Animals , Biological Availability , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Haplorhini , Pyridones/administration & dosage , Pyridones/chemistry , Pyridones/pharmacokinetics , Structure-Activity RelationshipABSTRACT
The synthesis of 4-(1',1'-dioxo-1',4'-dihydro-1'lambda(6)-benzo[1',2',4']thiadiazin-3'-yl)-5-hydroxy-2H-pyridazin-3-ones bearing 6-amino substituents as potent inhibitors of the HCV RNA-dependent RNA polymerase (NS5B) is described. Several of these agents also display potent antiviral activity in cell culture experiments (EC(50)<0.10 microM). In vitro DMPK data (microsome t(1/2), Caco-2 P(app)) for many of the compounds are also disclosed, and a crystal structure of a representative inhibitor complexed with the NS5B protein is discussed.
Subject(s)
Antiviral Agents/chemical synthesis , Chemistry, Pharmaceutical/methods , Cyclic S-Oxides/chemical synthesis , Pyridazines/chemistry , Pyridazines/chemical synthesis , Thiadiazines/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Antiviral Agents/pharmacology , Caco-2 Cells , Crystallography, X-Ray/methods , Cyclic S-Oxides/pharmacology , DNA-Directed RNA Polymerases/chemistry , Drug Design , Genotype , Humans , Inhibitory Concentration 50 , Microsomes/metabolism , Models, Chemical , Molecular Conformation , Pyridazines/pharmacology , Structure-Activity Relationship , Thiadiazines/pharmacologyABSTRACT
4-(1,1-Dioxo-1,4-dihydro-1lambda(6)-benzo[1,4]thiazin-3-yl)-5-hydroxy-2H-pyridazin-3-one analogs were discovered as a novel class of inhibitors of HCV NS5B polymerase. Structure-based design led to the identification of compound 3a that displayed potent inhibitory activities in biochemical and replicon assays (1b IC(50)<10 nM; 1b EC(50)=1.1 nM) as well as good stability toward human liver microsomes (HLM t(1/2)>60 min).
Subject(s)
Chemistry, Pharmaceutical/methods , Hepacivirus/enzymology , Microsomes, Liver/enzymology , Pyridazines/chemical synthesis , Pyridazines/pharmacology , Thiazines/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Caco-2 Cells , Crystallography, X-Ray/methods , Drug Design , Hepacivirus/drug effects , Humans , Inhibitory Concentration 50 , Models, Chemical , Molecular Conformation , Pyridazines/chemistry , Structure-Activity Relationship , Thiazines/chemistry , Thiazines/pharmacology , Time FactorsABSTRACT
A novel series of HCV NS5B polymerase inhibitors comprising 1,1-dioxoisothiazoles and benzo[b]thiophene-1,1-dioxides were designed, synthesized, and evaluated. SAR studies guided by structure-based design led to the identification of a number of potent NS5B inhibitors with nanomolar IC(50) values. The most potent compound exhibited IC(50) less than 10nM against the genotype 1b HCV polymerase and EC(50) of 70 nM against a genotype 1b replicon in cell culture. The DMPK properties of selected compounds were also evaluated.
Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacokinetics , Enzyme Inhibitors/pharmacokinetics , Thiazoles/chemical synthesis , Thiophenes/chemical synthesis , Viral Nonstructural Proteins/antagonists & inhibitors , Chemistry, Pharmaceutical/methods , Crystallography, X-Ray/methods , Drug Design , Genotype , Humans , Inhibitory Concentration 50 , Models, Chemical , Molecular Conformation , RNA, Viral/metabolism , Structure-Activity Relationship , Thiazoles/pharmacokinetics , Thiophenes/pharmacokineticsABSTRACT
Pyrrolo[1,2-b]pyridazin-2-one analogs were discovered as a novel class of inhibitors of genotype 1 HCV NS5B polymerase. Structure-based design led to the discovery of compound 3 k, which displayed potent inhibitory activities in biochemical and replicon assays (IC(50) (1b)<10nM; EC(50) (1b)=12 nM) as well as good stability towards human liver microsomes (HLM t(1/2)>60 min).
Subject(s)
Antiviral Agents/pharmacology , Pyridazines/pharmacology , Pyrroles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Binding Sites/drug effects , Cell Line , Crystallography, X-Ray , Humans , Hydrogen Bonding , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Pyridazines/chemical synthesis , Pyridazines/chemistry , Pyrroles/chemical synthesis , Pyrroles/chemistry , Structure-Activity Relationship , Viral Nonstructural Proteins/chemistryABSTRACT
5-Hydroxy-3(2H)-pyridazinone derivatives were investigated as inhibitors of genotype 1 HCV NS5B polymerase. Lead optimization led to the discovery of compound 3a, which displayed potent inhibitory activities in biochemical and replicon assays [IC(50) (1b)<10nM; IC(50) (1a)=22 nM; EC(50) (1b)=5nM], good stability toward human liver microsomes (HLM t(1/2)>60 min), and high ratios of liver to plasma concentrations 12h after a single oral administration to rats.
Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacokinetics , Hepacivirus/drug effects , Pyridazines/chemical synthesis , Pyridazines/pharmacokinetics , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Animals , Antiviral Agents/blood , Antiviral Agents/chemistry , Combinatorial Chemistry Techniques , Drug Design , Humans , Microsomes, Liver/drug effects , Molecular Structure , Pyridazines/blood , Pyridazines/chemistry , Rats , Structure-Activity RelationshipABSTRACT
5-Hydroxy-3(2H)-pyridazinone derivatives were investigated as inhibitors of genotype 1 HCV NS5B polymerase. The synthesis, structure-activity relationships (SAR), metabolic stability, and structure-based design approach for this new class of compounds are discussed.
Subject(s)
Benzothiadiazines/chemistry , Benzothiadiazines/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Pyridazines/chemistry , Pyridazines/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Benzothiadiazines/metabolism , Crystallography, X-Ray , Drug Design , Drug Stability , Enzyme Inhibitors/metabolism , Humans , Hydrogen Bonding , Inhibitory Concentration 50 , Microsomes, Liver/metabolism , Models, Molecular , Pyridazines/metabolism , RNA-Dependent RNA Polymerase/antagonists & inhibitors , RNA-Dependent RNA Polymerase/metabolism , Structure-Activity Relationship , Viral Nonstructural Proteins/metabolismABSTRACT
5-Hydroxy-3(2H)-pyridazinone derivatives were investigated as inhibitors of genotype 1 HCV NS5B polymerase. The structure-activity relationship (SAR) associated with variation of the pyridazinone 2- and 6-substituents is discussed. The synthesis and metabolic stability of this new class of compounds are also described.
