Optimization of a Novel Binding Motif to (E)-3-(3,5-Difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)acrylic Acid (AZD9496), a Potent and Orally Bioavailable Selective Estrogen Receptor Downregulator and Antagonist

J Med Chem. 2015 Oct 22;58(20):8128-40. doi: 10.1021/acs.jmedchem.5b00984. Epub 2015 Oct 7.


The discovery of an orally bioavailable selective estrogen receptor downregulator (SERD) with equivalent potency and preclinical pharmacology to the intramuscular SERD fulvestrant is described. A directed screen identified the 1-aryl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole motif as a novel, druglike ER ligand. Aided by crystal structures of novel ligands bound to an ER construct, medicinal chemistry iterations led to (E)-3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)acrylic acid (30b, AZD9496), a clinical candidate with high oral bioavailability across preclinical species that is currently being evaluated in phase I clinical trials for the treatment of advanced estrogen receptor (ER) positive breast cancer.

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / metabolism*
  • Breast Neoplasms / drug therapy
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cinnamates / chemistry*
  • Cinnamates / metabolism*
  • Clinical Trials, Phase I as Topic
  • Down-Regulation / drug effects
  • Drug Design
  • Estrogen Antagonists / chemical synthesis*
  • Estrogen Antagonists / pharmacology*
  • Estrogen Receptor Modulators / chemical synthesis*
  • Estrogen Receptor Modulators / pharmacology*
  • Female
  • Humans
  • Indoles / chemistry*
  • Indoles / metabolism*
  • Injections, Intramuscular
  • X-Ray Diffraction


  • AZD9496
  • Antineoplastic Agents
  • Cinnamates
  • Estrogen Antagonists
  • Estrogen Receptor Modulators
  • Indoles