Discovery of the 3-Imino-1,2,4-thiadiazinane 1,1-Dioxide Derivative Verubecestat (MK-8931)-A β-Site Amyloid Precursor Protein Cleaving Enzyme 1 Inhibitor for the Treatment of Alzheimer's Disease

J Med Chem. 2016 Dec 8;59(23):10435-10450. doi: 10.1021/acs.jmedchem.6b00307. Epub 2016 Nov 18.


Verubecestat 3 (MK-8931), a diaryl amide-substituted 3-imino-1,2,4-thiadiazinane 1,1-dioxide derivative, is a high-affinity β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor currently undergoing Phase 3 clinical evaluation for the treatment of mild to moderate and prodromal Alzheimer's disease. Although not selective over the closely related aspartyl protease BACE2, verubecestat has high selectivity for BACE1 over other key aspartyl proteases, notably cathepsin D, and profoundly lowers CSF and brain Aβ levels in rats and nonhuman primates and CSF Aβ levels in humans. In this annotation, we describe the discovery of 3, including design, validation, and selected SAR around the novel iminothiadiazinane dioxide core as well as aspects of its preclinical and Phase 1 clinical characterization.

MeSH terms

  • Alzheimer Disease / drug therapy*
  • Alzheimer Disease / metabolism
  • Amyloid beta-Protein Precursor / antagonists & inhibitors*
  • Amyloid beta-Protein Precursor / metabolism
  • Animals
  • Cyclic S-Oxides / chemical synthesis
  • Cyclic S-Oxides / chemistry
  • Cyclic S-Oxides / pharmacology*
  • Dogs
  • Dose-Response Relationship, Drug
  • Drug Discovery*
  • Humans
  • Macaca fascicularis
  • Models, Molecular
  • Molecular Structure
  • Rats
  • Rats, Sprague-Dawley
  • Structure-Activity Relationship
  • Thiadiazines / chemical synthesis
  • Thiadiazines / chemistry
  • Thiadiazines / pharmacology*


  • Amyloid beta-Protein Precursor
  • Cyclic S-Oxides
  • Thiadiazines
  • verubecestat