Imatinib as a paradigm of targeted cancer therapies

Abstract

Imatinib (Glivec®, Novartis Pharmaceuticals, Basel, Switzerland) exemplifies the successful development of a rationally designed, molecularly targeted therapy for the treatment of a specific cancer. The identification of the breakpoint cluster region – Abelson murine leukaemia viral oncogene homologue 1 (BCR – ABL) tyrosine kinase as a therapeutic target in chronic myeloid leukaemia and the steps in the development of an agent to specifically inactivate this abnormality will be described. The unprecedented results of clinical trials will be reviewed along with a description of resistance mechanisms and the development of novel tyrosine kinase inhibitors to circumvent resistance. As imatinib also inhibits the tyrosine kinase activity of KIT and the platelet-derived growth factor receptors, the extension of imatinib to malignancies driven by these kinases is described. Finally, the application of the paradigm of targeting molecular pathogenetic events to other malignancies is explored.