News
Based on current data for GIST sensitivity to TKIs, Dr. Trent and Dr. Demetri summarized the current GIST mutation and treatment landscape this way:
• About 60% of GIST have the most common tyrosine kinase mutation, in exon 11 of the KIT gene, and are sensitive to 400 mg/day of imatinib.
• About 7% of GIST have the exon 9 mutation of KIT and are sensitive to a higher dosage of imatinib, ideally 800 mg/day if that is tolerated.
• About 20% of GIST have the D842V mutation in the PDGFRA tyrosine kinase gene, and these patients are candidates for enrollment in a trial, as no regimens are known effective for these tumors.
• About 12% of GIST have a mutation in the SDF gene, which appears to make them resistant to imatinib and sunitinib but which may be sensitive to another TKI, regorafenib.
• The remaining GIST have other, rare mutations.
Dr. Trent said that he had no disclosures. Dr. Demetri said that he has been a consultant to Bayer, Novartis, and other companies. Dr. Maki said that he has been a consultant to Eisai/Morphotek, Bayer, and other companies, and has received research support from Eisai/Morphotek, Tracon, and Bayer. Dr. Benjamin said that he has been a consultant to Johnson & Johnson, Merck, and Pfizer.
On Twitter @mitchelzoler