Nucleotide prodrugs of 2'-deoxy-2'-spirooxetane ribonucleosides as novel inhibitors of the HCV NS5B polymerase

J Med Chem. 2014 Mar 13;57(5):1836-44. doi: 10.1021/jm4015422. Epub 2014 Jan 6.

Abstract

The limited efficacy, in particular against the genotype 1 virus, as well as the variety of side effects associated with the current therapy for hepatitis C virus (HCV) infection necessitates more efficacious drugs. We found that phosphoramidate prodrugs of 2'-deoxy-2'-spirooxetane ribonucleosides form a novel class of HCV NS5B RNA-dependent RNA polymerase inhibitors, displaying EC50 values ranging from 0.2 to >98 μM, measured in the Huh7-replicon cell line, with no apparent cytotoxicity (CC50 > 98.4 μM). Confirming recent findings, the 2'-spirooxetane moiety was identified as a novel structural motif in the field of anti-HCV nucleosides. A convenient synthesis was developed that enabled the synthesis of a broad set of nucleotide prodrugs with varying substitution patterns. Extensive formation of the triphosphate metabolite was observed in both rat and human hepatocyte cultures. In addition, after oral dosing of several phosphoramidate derivatives of compound 21 to rats, substantial hepatic levels of the active triphosphate metabolite were found.

MeSH terms

  • Animals
  • Antiviral Agents / chemistry
  • Antiviral Agents / pharmacokinetics
  • Antiviral Agents / pharmacology*
  • Area Under Curve
  • Drug Evaluation, Preclinical
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Hepacivirus / drug effects*
  • Hepacivirus / enzymology
  • Humans
  • Magnetic Resonance Spectroscopy
  • Prodrugs / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Ribonucleosides / chemistry
  • Ribonucleosides / pharmacokinetics
  • Ribonucleosides / pharmacology*
  • Viral Nonstructural Proteins / antagonists & inhibitors*

Substances

  • Antiviral Agents
  • Enzyme Inhibitors
  • Prodrugs
  • Ribonucleosides
  • Viral Nonstructural Proteins
  • NS-5 protein, hepatitis C virus