imatinib
Pronunciation: eye-MAT-ih-nib
A targeted therapy drug that inhibits specific protein kinases, primarily used to treat gastrointestinal stromal tumors (GISTs).
Full Definition
Imatinib is an oral tyrosine kinase inhibitor that specifically targets BCR-ABL, KIT, and PDGFRA proteins, revolutionizing the treatment of gastrointestinal stromal tumors (GISTs). Originally developed for chronic myeloid leukemia, imatinib became the first-line treatment for advanced and metastatic GISTs after demonstrating remarkable efficacy in tumors with KIT mutations. The drug works by blocking the ATP-binding site of these kinases, preventing tumor cell proliferation and inducing apoptosis. Resistance can develop over time, often due to secondary mutations in the KIT gene, leading to the need for second-line agents like sunitinib or regorafenib. Genetic testing for KIT and PDGFRA mutations is essential before starting therapy, as different mutation types have varying responses to treatment.
Usage
Usage note: Generic name; brand name is Gleevec (capitalize); verify mutation status before prescribing.
In Context
- "The patient's GIST showed an excellent response to imatinib therapy with significant tumor shrinkage on follow-up imaging." — Oncology treatment response note
- "Molecular testing confirmed a KIT exon 11 mutation, predicting good sensitivity to first-line imatinib treatment." — Pathology molecular report