Design and Discovery of N-(2-Methyl-5'-morpholino-6'-((tetrahydro-2H-pyran-4-yl)oxy)-[3,3'-bipyridin]-5-yl)-3-(trifluoromethyl)benzamide (RAF709): A Potent, Selective, and Efficacious RAF Inhibitor Targeting RAS Mutant Cancers

J Med Chem. 2017 Jun 22;60(12):4869-4881. doi: 10.1021/acs.jmedchem.6b01862. Epub 2017 Jun 8.


RAS oncogenes have been implicated in >30% of human cancers, all representing high unmet medical need. The exquisite dependency on CRAF kinase in KRAS mutant tumors has been established in genetically engineered mouse models and human tumor cells. To date, many small molecule approaches are under investigation to target CRAF, yet kinase-selective and cellular potent inhibitors remain challenging to identify. Herein, we describe 14 (RAF709) [ Aversa , Biaryl amide compounds as kinase inhibitors and their preparation . WO 2014151616, 2014 ], a selective B/C RAF inhibitor, which was developed through a hypothesis-driven approach focusing on drug-like properties. A key challenge encountered in the medicinal chemistry campaign was maintaining a balance between good solubility and potent cellular activity (suppression of pMEK and proliferation) in KRAS mutant tumor cell lines. We investigated the small molecule crystal structure of lead molecule 7 and hypothesized that disruption of the crystal packing would improve solubility, which led to a change from N-methylpyridone to a tetrahydropyranyl oxy-pyridine derivative. 14 proved to be soluble, kinase selective, and efficacious in a KRAS mutant xenograft model.

MeSH terms

  • 2,2'-Dipyridyl / analogs & derivatives*
  • 2,2'-Dipyridyl / chemistry
  • 2,2'-Dipyridyl / pharmacology
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology*
  • Benzamides / chemistry
  • Benzamides / pharmacology*
  • Crystallography, X-Ray
  • Dogs
  • Drug Design
  • Drug Discovery
  • Drug Stability
  • Humans
  • Inhibitory Concentration 50
  • Mice
  • Molecular Targeted Therapy
  • Neoplasms / drug therapy
  • Neoplasms / genetics
  • Proto-Oncogene Proteins B-raf / chemistry
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Rats
  • Structure-Activity Relationship
  • Xenograft Model Antitumor Assays
  • raf Kinases / antagonists & inhibitors*
  • ras Proteins / genetics*


  • Antineoplastic Agents
  • Benzamides
  • KRAS protein, human
  • RAF709
  • 2,2'-Dipyridyl
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • raf Kinases
  • Proto-Oncogene Proteins p21(ras)
  • ras Proteins