Discovery of 2-{3-[2-(1-isopropyl-3-methyl-1H-1,2-4-triazol-5-yl)-5,6-dihydrobenzo[f]imidazo[1,2-d][1,4]oxazepin-9-yl]-1H-pyrazol-1-yl}-2-methylpropanamide (GDC-0032): a β-sparing phosphoinositide 3-kinase inhibitor with high unbound exposure and robust in vivo antitumor activity

J Med Chem. 2013 Jun 13;56(11):4597-610. doi: 10.1021/jm4003632. Epub 2013 Jun 3.


Dysfunctional signaling through the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway leads to uncontrolled tumor proliferation. In the course of the discovery of novel benzoxepin PI3K inhibitors, we observed a strong dependency of in vivo antitumor activity on the free-drug exposure. By lowering the intrinsic clearance, we derived a set of imidazobenzoxazepin compounds that showed improved unbound drug exposure and effectively suppressed growth of tumors in a mouse xenograft model at low drug dose levels. One of these compounds, GDC-0032 (11l), was progressed to clinical trials and is currently under phase I evaluation as a potential treatment for human malignancies.

MeSH terms

  • Animals
  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • Drug Screening Assays, Antitumor
  • Female
  • Hepatocytes / metabolism
  • Humans
  • Imidazoles / chemical synthesis*
  • Imidazoles / pharmacokinetics
  • Imidazoles / pharmacology
  • In Vitro Techniques
  • Isoenzymes / antagonists & inhibitors
  • Mice
  • Mice, Nude
  • Microsomes, Liver / metabolism
  • Neoplasm Transplantation
  • Oxazepines / chemical synthesis*
  • Oxazepines / pharmacokinetics
  • Oxazepines / pharmacology
  • Phosphoinositide-3 Kinase Inhibitors*
  • Structure-Activity Relationship
  • Transplantation, Heterologous


  • 2-(3-(2-(1-isopropyl-3-methyl-1H-1,2-4-triazol-5-yl)-5,6-dihydrobenzo(f)imidazo(1,2-d)(1,4)oxazepin-9-yl)-1H-pyrazol-1-yl)-2-methylpropanamide
  • Antineoplastic Agents
  • Imidazoles
  • Isoenzymes
  • Oxazepines
  • Phosphoinositide-3 Kinase Inhibitors