title: 2'-deoxy-4'-azido nucleoside analogs are highly potent inhibitors of hepatitis C virus replication despite the lack of 2'-alpha-hydroxyl groups.
abstract: RNA polymerases effectively discriminate against deoxyribonucleotides and specifically recognize ribonucleotide substrates most likely through direct hydrogen bonding interaction with the 2'-alpha-hydroxy moieties of ribonucleosides. Therefore, ribonucleoside analogs as inhibitors of viral RNA polymerases have mostly been designed to retain hydrogen bonding potential at this site for optimal inhibitory potency. Here, two novel nucleoside triphosphate analogs are described, which are efficiently incorporated into nascent RNA by the RNA-dependent RNA polymerase NS5B of hepatitis C virus (HCV), causing chain termination, despite the lack of alpha-hydroxy moieties. 2'-deoxy-2'-beta-fluoro-4'-azidocytidine (RO-0622) and 2'-deoxy-2'-beta-hydroxy-4'-azidocytidine (RO-9187) were excellent substrates for deoxycytidine kinase and were phosphorylated with efficiencies up to 3-fold higher than deoxycytidine. As compared with previous reports on ribonucleosides, higher levels of triphosphate were formed from RO-9187 in primary human hepatocytes, and both compounds were potent inhibitors of HCV virus replication in the replicon system (IC(50) = 171 +/- 12 nM and 24 +/- 3 nM for RO-9187 and RO-0622, respectively; CC(50) >1 mM for both). Both compounds inhibited RNA synthesis by HCV polymerases from either HCV genotypes 1a and 1b or containing S96T or S282T point mutations with similar potencies, suggesting no cross-resistance with either R1479 (4'-azidocytidine) or 2'-C-methyl nucleosides. Pharmacokinetic studies with RO-9187 in rats and dogs showed that plasma concentrations exceeding HCV replicon IC(50) values 8-150-fold could be achieved by low dose (10 mg/kg) oral administration. Therefore, 2'-alpha-deoxy-4'-azido nucleosides are a new class of antiviral nucleosides with promising preclinical properties as potential medicines for the treatment of HCV infection.
authors.affiliation: Roche Palo Alto LLC, Palo Alto, California 94304, USA. Klaus.klumpp@roche.com
authors.forename: Klaus
authors.initials: K
authors.lastname: Klumpp
authors.forename: Genadiy
authors.initials: G
authors.lastname: Kalayanov
authors.forename: Han
authors.initials: H
authors.lastname: Ma
authors.forename: Sophie
authors.initials: S
authors.lastname: Le Pogam
authors.forename: Vincent
authors.initials: V
authors.lastname: Leveque
authors.forename: Wen-Rong
authors.initials: WR
authors.lastname: Jiang
authors.forename: Nicole
authors.initials: N
authors.lastname: Inocencio
authors.forename: Anniek
authors.initials: A
authors.lastname: De Witte
authors.forename: Sonal
authors.initials: S
authors.lastname: Rajyaguru
authors.forename: Ezra
authors.initials: E
authors.lastname: Tai
authors.forename: Sushmita
authors.initials: S
authors.lastname: Chanda
authors.forename: Michael R
authors.initials: MR
authors.lastname: Irwin
authors.forename: Christian
authors.initials: C
authors.lastname: Sund
authors.forename: Anna
authors.initials: A
authors.lastname: Winqist
authors.forename: Tatiana
authors.initials: T
authors.lastname: Maltseva
authors.forename: Staffan
authors.initials: S
authors.lastname: Eriksson
authors.forename: Elena
authors.initials: E
authors.lastname: Usova
authors.forename: Mark
authors.initials: M
authors.lastname: Smith
authors.forename: Andre
authors.initials: A
authors.lastname: Alker
authors.forename: Isabel
authors.initials: I
authors.lastname: Najera
authors.forename: Nick
authors.initials: N
authors.lastname: Cammack
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Martin
authors.forename: Nils Gunnar
authors.initials: NG
authors.lastname: Johansson
authors.forename: David B
authors.initials: DB
authors.lastname: Smith
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D004285:Dogs; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D005838:Genotype; D016174:Hepacivirus / Q000201:enzymology* / Q000235:genetics; D006526:Hepatitis C / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000821:virology; D022781:Hepatocytes / Q000201:enzymology / Q000821:virology; D006801:Humans; D012367:RNA, Viral / Q000096:biosynthesis / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012263:Ribonucleosides / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D014779:Virus Replication / Q000187:drug effects* / Q000502:physiology
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D012367:RNA, Viral; D012263:Ribonucleosides; D012324:RNA-Dependent RNA Polymerase