title: Resensitizing daclatasvir-resistant hepatitis C variants by allosteric modulation of NS5A.
abstract: It is estimated that more than 170 million people are infected with hepatitis C virus (HCV) worldwide. Clinical trials have demonstrated that, for the first time in human history, the potential exists to eradicate a chronic viral disease using combination therapies that contain only direct-acting antiviral agents. HCV non-structural protein 5A (NS5A) is a multifunctional protein required for several stages of the virus replication cycle. NS5A replication complex inhibitors, exemplified by daclatasvir (DCV; also known as BMS-790052 and Daklinza), belong to the most potent class of direct-acting anti-HCV agents described so far, with in vitro activity in the picomolar (pM) to low nanomolar (nM) range. The potency observed in vitro has translated into clinical efficacy, with HCV RNA declining by ~3-4 log10 in infected patients after administration of single oral doses of DCV. Understanding the exceptional potency of DCV was a key objective of this study. Here we show that although DCV and an NS5A inhibitor analogue (Syn-395) are inactive against certain NS5A resistance variants, combinations of the pair enhance DCV potency by >1,000-fold, restoring activity to the pM range. This synergistic effect was validated in vivo using an HCV-infected chimaeric mouse model. The cooperative interaction of a pair of compounds suggests that NS5A protein molecules communicate with each other: one inhibitor binds to resistant NS5A, causing a conformational change that is transmitted to adjacent NS5As, resensitizing resistant NS5A so that the second inhibitor can act to restore inhibition. This unprecedented synergistic anti-HCV activity also enhances the resistance barrier of DCV, providing additional options for HCV combination therapy and new insight into the role of NS5A in the HCV replication cycle.
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Sun
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Donald R
authors.initials: DR
authors.lastname: O'Boyle
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Fridell
authors.affiliation: Computer-Assisted Drug Design, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Langley
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Chunfu
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Nower
authors.affiliation: Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Johnson
authors.affiliation: Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Frederic
authors.initials: F
authors.lastname: Moulin
authors.affiliation: Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Nophsker
authors.affiliation: Leads Discovery and Optimization, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Ying-Kai
authors.initials: YK
authors.lastname: Wang
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Mengping
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Rigat
authors.affiliation: Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Piyasena
authors.initials: P
authors.lastname: Hewawasam
authors.affiliation: Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: John
authors.initials: J
authors.lastname: Kadow
authors.affiliation: Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Meanwell
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Cockett
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lemm
authors.affiliation: Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Kramer
authors.affiliation: Discovery Chemistry, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Makonen
authors.initials: M
authors.lastname: Belema
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002219:Carbamates; D002460:Cell Line; D024882:Drug Resistance, Viral / Q000187:drug effects*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D006526:Hepatitis C / Q000821:virology; D022781:Hepatocytes / Q000637:transplantation; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D051379:Mice; D008958:Models, Molecular; D011487:Protein Conformation / Q000187:drug effects; D055503:Protein Multimerization / Q000187:drug effects; D020836:Protein Structure, Quaternary / Q000187:drug effects; D011759:Pyrrolidines; D015203:Reproducibility of Results; D014633:Valine / Q000031:analogs & derivatives; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000187:drug effects; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D001713:Biphenyl Compounds; D002219:Carbamates; D007093:Imidazoles; D011759:Pyrrolidines; D014633:Valine; D017361:Viral Nonstructural Proteins; C000603342:Syn-395; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase; C549273:daclatasvir