title: Synergistic Activity of Combined NS5A Inhibitors.
abstract: Daclatasvir (DCV) is a first-in-class hepatitis C virus (HCV) nonstructural 5A replication complex inhibitor (NS5A RCI) that is clinically effective in interferon-free combinations with direct-acting antivirals (DAAs) targeting alternate HCV proteins. Recently, we reported NS5A RCI combinations that enhance HCV inhibitory potential in vitro, defining a new class of HCV inhibitors termed NS5A synergists (J. Sun, D. R. O'Boyle II, R. A. Fridell, D. R. Langley, C. Wang, S. Roberts, P. Nower, B. M. Johnson F. Moulin, M. J. Nophsker, Y. Wang, M. Liu, K. Rigat, Y. Tu, P. Hewawasam, J. Kadow, N. A. Meanwell, M. Cockett, J. A. Lemm, M. Kramer, M. Belema, and M. Gao, Nature 527:245-248, 2015, doi:10.1038/nature15711). To extend the characterization of NS5A synergists, we tested new combinations of DCV and NS5A synergists against genotype (gt) 1 to 6 replicons and gt 1a, 2a, and 3a viruses. The kinetics of inhibition in HCV-infected cells treated with DCV, an NS5A synergist (NS5A-Syn), or a combination of DCV and NS5A-Syn were distinctive. Similar to activity observed clinically, DCV caused a multilog drop in HCV, followed by rebound due to the emergence of resistance. DCV-NS5A-Syn combinations were highly efficient at clearing cells of viruses, in line with the trend seen in replicon studies. The retreatment of resistant viruses that emerged using DCV monotherapy with DCV-NS5A-Syn resulted in a multilog drop and rebound in HCV similar to the initial decline and rebound observed with DCV alone on wild-type (WT) virus. A triple combination of DCV, NS5A-Syn, and a DAA targeting the NS3 or NS5B protein cleared the cells of viruses that are highly resistant to DCV. Our data support the observation that the cooperative interaction of DCV and NS5A-Syn potentiates both the genotype coverage and resistance barrier of DCV, offering an additional DAA option for combination therapy and tools for explorations of NS5A function.
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA oboyled@bms.com.
authors.forename: Donald R
authors.initials: DR
authors.lastname: O'Boyle
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Nower
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Fridell
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Chunfu
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Piyasena
authors.initials: P
authors.lastname: Hewawasam
authors.affiliation: Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Omar
authors.initials: O
authors.lastname: Lopez
authors.affiliation: Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Meanwell
authors.affiliation: Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Makonen
authors.initials: M
authors.lastname: Belema
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Cockett
authors.affiliation: Department of Virology, Bristol-Myers Squibb Research and Development, Wallingford, Connecticut, USA.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Sun
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002219:Carbamates; D002460:Cell Line; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D016174:Hepacivirus / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D062105:Molecular Docking Simulation; D011759:Pyrrolidines; D012093:Replicon / Q000187:drug effects / Q000235:genetics; D014633:Valine / Q000031:analogs & derivatives; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; 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