title: Emerging Agents for the Treatment of Advanced, Imatinib-Resistant Gastrointestinal Stromal Tumors: Current Status and Future Directions.
abstract: Imatinib is strongly positioned as the recommended first-line agent for most patients with advanced gastrointestinal stromal tumor (GIST) due to its good efficacy and tolerability. Imatinib-resistant advanced GIST continues to pose a therapeutic challenge, likely due to the frequent presence of multiple mutations that confer drug resistance. Sunitinib and regorafenib are approved as second- and third-line agents, respectively, for patients whose GIST does not respond to imatinib or who do not tolerate imatinib, and their use is supported by large randomized trials. ATP-mimetic tyrosine kinase inhibitors provide clinical benefit even in heavily pretreated GIST suggesting that oncogenic dependency on KIT frequently persists. Several potentially useful tyrosine kinase inhibitors with distinct inhibitory profiles against both KIT ATP-binding domain and activation loop mutations have not yet been fully evaluated. Agents that have been found promising in preclinical models and early clinical trials include small molecule KIT and PDGFRA mutation-specific inhibitors, heat shock protein inhibitors, histone deacetylase inhibitors, allosteric KIT inhibitors, KIT and PDGFRA signaling pathway inhibitors, and immunological approaches including antibody-drug conjugates. Concomitant or sequential administration of tyrosine kinase inhibitors with KIT signaling pathway inhibitors require further evaluation, as well as rotation of tyrosine kinase inhibitors as a means to suppress drug-resistant cell clones.
authors.affiliation: Sarcoma Center, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bauer
authors.forename: Heikki
authors.initials: H
authors.lastname: Joensuu
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D055808:Drug Discovery / Q000639:trends*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D015507:Drugs, Investigational / Q000009:adverse effects / Q000627:therapeutic use*; D005544:Forecasting; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D006801:Humans; D000068877:Imatinib Mesylate / Q000009:adverse effects / Q000627:therapeutic use*; D058990:Molecular Targeted Therapy; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D015507:Drugs, Investigational; D047428:Protein Kinase Inhibitors; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases