Imatinib mesylate is an orally administered, synthetic tyrosine kinase inhibitor (three known targets are ABL, c-kit, PDGF receptor). It is rapidly absorbed , and is highly bioavailable. Most of imatinib is eliminated as metabolites, only 25% of it is eliminated unchanged. The half-lives of imatinib and its main metabolite are 18 and 40 hours respectively.

It is used in the treatment of chronic myeloid leukaemia (CML) and GIST. It is also approved as a single agent for the treatment of dermatofibrosarcoma protuberans (DFSP), myelodysplastic / myeloproliferative diseases (MDS/MPD), aggressive systemic mastocytosis (ASM), hypereosinophilic syndrome/chronic eosinophilic leukemia (HES/CEL), and relapsed/refractory Philadelphia chromosome positive acute lymphocytic leukemia (Ph+ ALL).