Imatinib, is a tyrosine kinase inhibitor that inhibits the BCR-ABL tyrosine kinase created by the Philadelphia chromosome abnormality in chronic myeloid leukaemia (CML). It blocks proliferation and induces apoptosis in BCR-ABL positive cell lines, as well as fresh leukaemic cells from Philadelphia chromosome positive CML. Imatinib also inhibits receptor kinases for platelet-derived growth factor (PDGF) and stem cell factor (SCF), c-kit, PDGF- and SCF-mediated cellular events.