Identification of a Potent, Highly Selective, and Brain Penetrant Phosphodiesterase 2A Inhibitor Clinical Candidate

J Med Chem. 2018 Feb 8;61(3):1001-1018. doi: 10.1021/acs.jmedchem.7b01466. Epub 2018 Jan 16.

Abstract

Computational modeling was used to direct the synthesis of analogs of previously reported phosphodiesterase 2A (PDE2A) inhibitor 1 with an imidazotriazine core to yield compounds of significantly enhanced potency. The analog PF-05180999 (30) was subsequently identified as a preclinical candidate targeting cognitive impairment associated with schizophrenia. Compound 30 demonstrated potent binding to PDE2A in brain tissue, dose responsive mouse brain cGMP increases, and reversal of N-methyl-d-aspartate (NMDA) antagonist-induced (MK-801, ketamine) effects in electrophysiology and working memory models in rats. Preclinical pharmacokinetics revealed unbound brain/unbound plasma levels approaching unity and good oral bioavailability resulting in an average concentration at steady state (Cav,ss) predicted human dose of 30 mg once daily (q.d.). Modeling of a modified release formulation suggested that 25 mg twice daily (b.i.d.) could maintain plasma levels of 30 at or above targeted efficacious plasma levels for 24 h, which became part of the human clinical plan.

MeSH terms

  • Animals
  • Biological Availability
  • Brain / drug effects*
  • Brain / metabolism*
  • Brain / physiology
  • Cyclic Nucleotide Phosphodiesterases, Type 2 / antagonists & inhibitors*
  • Cyclic Nucleotide Phosphodiesterases, Type 2 / chemistry
  • Cyclic Nucleotide Phosphodiesterases, Type 2 / metabolism
  • Dose-Response Relationship, Drug
  • Drug Discovery*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / metabolism*
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Imidazoles / chemistry
  • Imidazoles / metabolism
  • Imidazoles / pharmacokinetics
  • Imidazoles / pharmacology
  • Inhibitory Concentration 50
  • Memory, Short-Term / drug effects
  • Molecular Docking Simulation
  • Protein Conformation

Substances

  • Enzyme Inhibitors
  • Imidazoles
  • Cyclic Nucleotide Phosphodiesterases, Type 2