In vivo eradication of human BCR/ABL-positive leukemia cells with an ABL kinase inhibitor

J Natl Cancer Inst. 1999 Jan 20;91(2):163-8. doi: 10.1093/jnci/91.2.163.


Background: The leukemia cells of approximately 95% of patients with chronic myeloid leukemia and 30%-50% of adult patients with acute lymphoblastic leukemia express the Bcr/Abl oncoprotein, which is the product of a fusion gene created by a chromosomal translocation [(9:22) (q34;q11)]. This oncoprotein expresses a constitutive tyrosine kinase activity that is crucial for its cellular transforming activity. In this study, we evaluated the antineoplastic activity of CGP57148B, which is a competitive inhibitor of the Bcr/Abl tyrosine kinase.

Methods: Nude mice were given an injection of the Bcr/Abl-positive human leukemia cell lines KU812 or MC3. Tumor-bearing mice were treated intraperitoneally or orally with CGP57148B according to three different schedules. In vitro drug wash-out experiments and in vivo molecular pharmacokinetic experiments were performed to optimize the in vivo treatment schedule.

Results: Treatment schedules administering CGP57148B once or twice per day produced some inhibition of tumor growth, but no tumor-bearing mouse was cured. A single administration of CGP57148B caused substantial (>50%) but short-lived (2-5 hours) inhibition of Bcr/Abl kinase activity. On the basis of the results from in vitro wash-out experiments, 20-21 hours was defined as the duration of continuous exposure needed to block cell proliferation and to induce apoptosis in these two leukemia cell lines. A treatment regimen assuring the continuous block of the Bcr/Abl phosphorylating activity that was administered over an 11-day period cured 87%-100% of treated mice.

Conclusion: These data indicate that the continuous block of the oncogenic tyrosine kinase of Bcr/Abl protein is needed to produce important biologic effects in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Benzamides
  • Enzyme Inhibitors / pharmacology*
  • Fusion Proteins, bcr-abl / metabolism*
  • Humans
  • Imatinib Mesylate
  • Leukemia, Experimental / drug therapy*
  • Leukemia, Experimental / metabolism
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / metabolism
  • Mice
  • Piperazines / pharmacology*
  • Protein-Tyrosine Kinases / pharmacology*
  • Pyrimidines / pharmacology*
  • Signal Transduction / drug effects
  • Tumor Cells, Cultured


  • Antineoplastic Agents
  • Benzamides
  • Enzyme Inhibitors
  • Piperazines
  • Pyrimidines
  • Imatinib Mesylate
  • Protein-Tyrosine Kinases
  • Fusion Proteins, bcr-abl