Discovery and Optimization of Biaryl Alkyl Ethers as a Novel Class of Highly Selective, CNS-Penetrable, and Orally Active Adaptor Protein-2-Associated Kinase 1 (AAK1) Inhibitors for the Potential Treatment of Neuropathic Pain

J Med Chem. 2022 Mar 24;65(6):4534-4564. doi: 10.1021/acs.jmedchem.1c02132. Epub 2022 Mar 9.

Abstract

Recent mouse knockout studies identified adapter protein-2-associated kinase 1 (AAK1) as a viable target for treating neuropathic pain. BMS-986176/LX-9211 (4), as a highly selective, CNS-penetrable, and potent AAK1 inhibitor, has advanced into phase II human trials. On exploring the structure-activity relationship (SAR) around this biaryl alkyl ether chemotype, several additional compounds were found to be highly selective and potent AAK1 inhibitors with good druglike properties. Among these, compounds 43 and 58 showed very good efficacy in two neuropathic pain rat models and had excellent CNS penetration and spinal cord target engagement. Both compounds also exhibited favorable physicochemical and oral pharmacokinetic (PK) properties. Compound 58, a central pyridine isomer of BMS-986176/LX-9211 (4), was 4-fold more potent than 4 in vitro and showed lower plasma exposure needed to achieve similar efficacy compared to 4 in the CCI rat model. However, both 43 and 58 showed an inferior preclinical toxicity profile compared to 4.

MeSH terms

  • Anesthetics, General*
  • Animals
  • Ethers / therapeutic use
  • Mice
  • Neuralgia* / drug therapy
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Rats
  • Spinal Cord
  • Structure-Activity Relationship

Substances

  • Anesthetics, General
  • Ethers
  • Protein Kinase Inhibitors