Discovery of 3-[2-(imidazo[1,2-b]pyridazin-3-yl)ethynyl]-4-methyl-N-{4-[(4-methylpiperazin-1-yl)methyl]-3-(trifluoromethyl)phenyl}benzamide (AP24534), a potent, orally active pan-inhibitor of breakpoint cluster region-abelson (BCR-ABL) kinase including the T315I gatekeeper mutant

J Med Chem. 2010 Jun 24;53(12):4701-19. doi: 10.1021/jm100395q.


In the treatment of chronic myeloid leukemia (CML) with BCR-ABL kinase inhibitors, the T315I gatekeeper mutant has emerged as resistant to all currently approved agents. This report describes the structure-guided design of a novel series of potent pan-inhibitors of BCR-ABL, including the T315I mutation. A key structural feature is the carbon-carbon triple bond linker which skirts the increased bulk of Ile315 side chain. Extensive SAR studies led to the discovery of development candidate 20g (AP24534), which inhibited the kinase activity of both native BCR-ABL and the T315I mutant with low nM IC(50)s, and potently inhibited proliferation of corresponding Ba/F3-derived cell lines. Daily oral administration of 20g significantly prolonged survival of mice injected intravenously with BCR-ABL(T315I) expressing Ba/F3 cells. These data, coupled with a favorable ADME profile, support the potential of 20g to be an effective treatment for CML, including patients refractory to all currently approved therapies.

MeSH terms

  • Administration, Oral
  • Animals
  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Blood-Brain Barrier / metabolism
  • Cell Line, Tumor
  • Crystallography, X-Ray
  • Drug Screening Assays, Antitumor
  • Fusion Proteins, bcr-abl / antagonists & inhibitors*
  • Fusion Proteins, bcr-abl / genetics
  • Imidazoles / chemical synthesis*
  • Imidazoles / pharmacokinetics
  • Imidazoles / pharmacology
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / mortality
  • Mice
  • Mice, SCID
  • Models, Molecular
  • Mutation
  • Protein Kinase Inhibitors / chemical synthesis*
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology
  • Pyridazines / chemical synthesis*
  • Pyridazines / pharmacokinetics
  • Pyridazines / pharmacology
  • Rats


  • Antineoplastic Agents
  • Imidazoles
  • Protein Kinase Inhibitors
  • Pyridazines
  • ponatinib
  • Fusion Proteins, bcr-abl