Imatinib mesylate for the treatment of gastrointestinal stromal tumor.

Gastrointestinal stromal tumors (GISTs) are rare neoplasms of mesenchymal origin arising in the GI tract. These tumors are characterized by activating mutations of either receptor tyrosine kinase KIT or PDGFRA, which are found in 85% of cases. The introduction of imatinib mesylate (IM), which targets the kinases presenting with these molecular alterations, has dramatically changed the management of these rare tumors, which were resistant to conventional cytotoxic chemotherapy, both in advanced and localized phases. IM is orally available, has a favorable safety profile and induces partial responses and disease stabilization in up to 80% of patients with advanced GIST. Recently, IM was approved for the postoperative treatment of patients with completely resected localized GIST.