Discovery of Potent, Selective, and Orally Available IRE1α Inhibitors Demonstrating Comparable PD Modulation to IRE1 Knockdown in a Multiple Myeloma Model

J Med Chem. 2024 Jun 13;67(11):8708-8729. doi: 10.1021/acs.jmedchem.3c02425. Epub 2024 May 15.

Abstract

The lack of selective and safe in vivo IRE1α tool molecules has limited the evaluation of IRE1α as a viable target to treat multiple myeloma. Focus on improving the physicochemical properties of a literature compound by decreasing lipophilicity, molecular weight, and basicity allowed the discovery of a novel series with a favorable in vitro safety profile and good oral exposure. These efforts culminated in the identification of a potent and selective in vivo tool compound, G-5758, that was well tolerated following multiday oral administration of doses up to 500 mg/kg. G-5758 demonstrated comparable pharmacodynamic effects to induced IRE1 knockdown as measured by XBP1s levels in a multiple myeloma model (KMS-11).

MeSH terms

  • Administration, Oral
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use
  • Cell Line, Tumor
  • Drug Discovery
  • Endoribonucleases* / antagonists & inhibitors
  • Endoribonucleases* / metabolism
  • Gene Knockdown Techniques
  • Humans
  • Mice
  • Multiple Myeloma* / drug therapy
  • Multiple Myeloma* / pathology
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Protein Serine-Threonine Kinases* / antagonists & inhibitors
  • Protein Serine-Threonine Kinases* / metabolism
  • Rats
  • Structure-Activity Relationship
  • X-Box Binding Protein 1 / genetics
  • X-Box Binding Protein 1 / metabolism

Substances

  • Protein Serine-Threonine Kinases
  • ERN1 protein, human
  • Endoribonucleases
  • Antineoplastic Agents
  • Protein Kinase Inhibitors
  • X-Box Binding Protein 1