Discovery of a Potent and Specific M. tuberculosis Leucyl-tRNA Synthetase Inhibitor: (S)-3-(Aminomethyl)-4-chloro-7-(2-hydroxyethoxy)benzo[c][1,2]oxaborol-1(3H)-ol (GSK656)

J Med Chem. 2017 Oct 12;60(19):8011-8026. doi: 10.1021/acs.jmedchem.7b00631. Epub 2017 Sep 27.

Abstract

There is an urgent need to develop new and safer antitubercular agents that possess a novel mode of action. We synthesized and evaluated a novel series of 3-aminomethyl 4-halogen benzoxaboroles as Mycobacterium tuberculosis (Mtb) leucyl-tRNA synthetase (LeuRS) inhibitors. A number of Mtb LeuRS inhibitors were identified that demonstrated good antitubercular activity with high selectivity over human mitochondrial and cytoplasmic LeuRS. Further evaluation of these Mtb LeuRS inhibitors by in vivo pharmacokinetics (PK) and murine tuberculosis (TB) efficacy models led to the discovery of GSK3036656 (abbreviated as GSK656). This molecule shows potent inhibition of Mtb LeuRS (IC50 = 0.20 μM) and in vitro antitubercular activity (Mtb H37Rv MIC = 0.08 μM). Additionally, it is highly selective for the Mtb LeuRS enzyme with IC50 of >300 μM and 132 μM for human mitochondrial LeuRS and human cytoplasmic LeuRS, respectively. In addition, it exhibits remarkable PK profiles and efficacy against Mtb in mouse TB infection models with superior tolerability over initial leads. This compound has been progressed to clinical development for the treatment of tuberculosis.

MeSH terms

  • Animals
  • Antitubercular Agents / chemical synthesis*
  • Antitubercular Agents / pharmacokinetics
  • Antitubercular Agents / pharmacology*
  • Boron Compounds / chemical synthesis
  • Boron Compounds / pharmacokinetics
  • Boron Compounds / pharmacology*
  • Drug Discovery
  • Enzyme Inhibitors / chemical synthesis*
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Female
  • Heterocyclic Compounds, 2-Ring / chemical synthesis
  • Heterocyclic Compounds, 2-Ring / pharmacology*
  • Humans
  • Leucine-tRNA Ligase / antagonists & inhibitors*
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / enzymology
  • Structure-Activity Relationship
  • Substrate Specificity

Substances

  • Antitubercular Agents
  • Boron Compounds
  • Enzyme Inhibitors
  • GSK656
  • Heterocyclic Compounds, 2-Ring
  • Leucine-tRNA Ligase