Imatinib is a targeted therapy drug primarily used in the treatment of certain types of cancers, most notably chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). It works by inhibiting the activity of specific tyrosine kinases, enzymes that play a crucial role in the signaling pathways that regulate cell division and survival. By blocking these enzymes, imatinib can effectively slow down or stop the growth of cancer cells.