A drug used to treat chronic myelogenous leukemia (CML). It is used in patients who cannot be treated with or have not gotten better with other treatment. It is also being studied in the treatment of other types of cancer. Bosutinib blocks the action of BCR-ABL and other proteins, which may help keep cancer cells from growing and may kill cancer cells. It is a type of tyrosine kinase inhibitor. Also called Bosulif.