Imatinib

Primarily used for Philadelphia chromosome-positive chronic myeloid leukemia (CML) in chronic phase. Also approved for newly diagnosed adult and pediatric patients with CML, adults with relapsed or refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL), pediatric patients with newly diagnosed Ph+ALL, adults with myelodysplastic/myeloproliferative diseases associated with PDGFR gene rearrangements, adults with aggressive systemic mastocytosis, adults with hypereosinophilic syndrome, adults with chronic eosinophilic leukemia, adults with unresectable and/or metastatic gastrointestinal stromal tumors (GIST), adjuvant treatment of GIST following complete surgical removal, and adults with dermatofibrosarcoma protuberans.

Imatinib mesylate is a protein-tyrosine kinase inhibitor that competitively inhibits the ATP-binding site of BCR-ABL tyrosine kinase and other related kinases. By blocking these abnormal kinases created by genetic mutations (such as the Philadelphia chromosome), it inhibits tumor cell proliferation and induces apoptosis in BCR-ABL positive cells. It also inhibits receptor tyrosine kinases for platelet-derived growth factor (PDGF) and stem cell factor (SCF).

Requires confirmation of Philadelphia chromosome or relevant genetic mutation before treatment. Must be taken with food and a large glass of water to reduce gastrointestinal irritation. Common side effects include fluid retention, nausea, muscle cramps, and fatigue. Can cause serious adverse effects including heart failure, liver toxicity, and bone marrow suppression. Multiple drug interactions exist; inform healthcare providers of all medications. Regular blood monitoring is necessary during treatment. Pregnancy category D - should not be used during pregnancy.