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, potent, and orally bioavailable class of product-like inhibitors of the HCV NS3 protease was discovered by constraining the P2-P3 amide bond and the P3 hydrocarbon substituent to the protease-bound conformation. This preorganization was accomplished by incorporation of the P2-P3 amide into a six-membered ring attached to the P2-proline 5-position. Isothermal calorimetric characterization of the role of hydrocarbon substitution of this six-membered ring, upon binding the HCV NS3 protease, was found to be exclusively entropic in nature. The synthesis, preliminary SAR and pharmacokinetic profiling of this compact, indolizidinone-derived scaffold are described.
Subject(s)
Enzyme Inhibitors/pharmacology , Indolizines/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Biological Availability , Crystallography, X-Ray , Dose-Response Relationship, Drug , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Indolizines/administration & dosage , Indolizines/chemistry , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Viral Nonstructural Proteins/metabolismABSTRACT
A potent and novel class of product-like inhibitors of the HCV NS3 protease was discovered by employing a phosphinic acid as a carboxylate isostere. The replicon activity and pharmacokinetic profile of this series of compounds was optimized by exploring the substitution of the phosphinic acid, as well as conformationally constraining these compounds through macrocyclization. The syntheses and preliminary biological evaluation of these phosphinic acids is described.
Subject(s)
Hepacivirus/drug effects , Hepacivirus/enzymology , Phosphinic Acids/chemical synthesis , Phosphinic Acids/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Administration, Oral , Cyclization , Humans , Inhibitory Concentration 50 , Molecular Structure , Phosphinic Acids/chemistryABSTRACT
Receptor tyrosine kinases (RTK), such as vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (KIT), and fms-like tyrosine kinase 3 (FLT3), are expressed in malignant tissues and act in concert, playing diverse and major roles in angiogenesis, tumor growth, and metastasis. With the exception of a few malignancies, seemingly driven by a single genetic mutation in a signaling protein, most tumors are the product of multiple mutations in multiple aberrant signaling pathways. Consequently, simultaneous targeted inhibition of multiple signaling pathways could be more effective than inhibiting a single pathway in cancer therapies. Such a multitargeted strategy has recently been validated in a number of preclinical and clinical studies using RTK inhibitors with broad target selectivity. SU14813, a small molecule identified from the same chemical library used to isolate sunitinib, has broad-spectrum RTK inhibitory activity through binding to and inhibition of VEGFR, PDGFR, KIT, and FLT3. In cellular assays, SU14813 inhibited ligand-dependent and ligand-independent proliferation, migration, and survival of endothelial cells and/or tumor cells expressing these targets. SU14813 inhibited VEGFR-2, PDGFR-beta, and FLT3 phosphorylation in xenograft tumors in a dose- and time-dependent fashion. The plasma concentration required for in vivo target inhibition was estimated to be 100 to 200 ng/mL. Used as monotherapy, SU14813 exhibited broad and potent antitumor activity resulting in regression, growth arrest, or substantially reduced growth of various established xenografts derived from human or rat tumor cell lines. Treatment in combination with docetaxel significantly enhanced both the inhibition of primary tumor growth and the survival of the tumor-bearing mice compared with administration of either agent alone. In summary, SU14813 inhibited target RTK activity in vivo in association with reduction in angiogenesis, target RTK-mediated proliferation, and survival of tumor cells, leading to broad and potent antitumor efficacy. These data support the ongoing phase I clinical evaluation of SU14813 in advanced malignancies.
Subject(s)
Angiogenesis Inhibitors/therapeutic use , Antineoplastic Agents/therapeutic use , Indoles/therapeutic use , Morpholines/therapeutic use , Neoplasms/drug therapy , Protein Kinase Inhibitors/therapeutic use , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/pharmacology , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Proliferation , Humans , Indoles/chemistry , Indoles/pharmacology , Mice , Morpholines/chemistry , Morpholines/pharmacology , Neoplasms/enzymology , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Rats , Receptor, Platelet-Derived Growth Factor beta/antagonists & inhibitors , Tumor Cells, Cultured , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors , Xenograft Model Antitumor AssaysABSTRACT
Modification of fumagillin was conducted to develop MetAP-2 inhibitors with desirable pharmacological properties. Replacement of the C4 side chain by benzyloxime preserves the inhibitory activity against MetAP-2 enzyme. Fumagillin analogues containing the C4 benzyloxime moiety were found to be very sensitive to the nature of the C6 substituent on the inhibition activity of HUVEC proliferation. This lack of correlation between MetAP-2 and HUVEC activities might be due to the cellular metabolism of the compounds by epoxide hydrolase, which is present in the cell. Compound (E)-3d, containing ethylpiperazinyl carbamate at C6 position, exhibited antiangiogenic effects similar to TNP-470 on matrigel plug assay and rat corneal micropocket assay.
