An orally bioavailable 2-phenylaminopyrimidine derivative with potential antineoplastic activity. Bafetinib specifically binds to and inhibits the Bcr/Abl fusion protein tyrosine kinase, an abnormal enzyme produced by Philadelphia chromosomal translocation associated with chronic myeloid leukemia (CML). This agent also inhibits the Src-family member Lyn tyrosine kinase, upregulated in imatinib-resistant CML cells and in a variety of solid cancer cell types. The inhibitory effect of bafetinib on these specific tyrosine kinases may decrease cellular proliferation and induce apoptosis in tumor cells that overexpress these kinases. CML patients may be refractory to imatinib, which sometimes results from point mutations occurring in the kinase domain of the Bcr/Abl fusion product. Due to its dual inhibitory activity, the use of bafetinib has been shown to overcome this particular drug resistance.