Bosutinib belongs to a pharmacological class of medicinal products known as kinase inhibitors. Bosutinib inhibits the abnormal BCR-ABL kinase that promotes CML. Modeling studies indicate that bosutinib binds the kinase domain of BCR-ABL. Bosutinib is also an inhibitor of Src family kinases including Src, Lyn and Hck. Bosutinib minimally inhibits platelet-derived growth factor (PDGF) receptor and c-Kit. In in vitro studies, bosutinib inhibits proliferation and survival of established CML cell lines, Ph+ ALL cell lines, and patient-derived primary primitive CML cells.