Imatinib is used to treat gastrointestinal stromal tumor (GIST). In patients with advanced GIST, the tumors initially shrink with imatinib treatment, but eventually most tumors begin to grow again. MEK162 is an investigational drug that has been shown in laboratory studies to help imatinib block the growth of GIST.
In this study, researchers want to find the highest dose of MEK162 that can be given with imatinib in patients with previously untreated advanced GIST, and to evaluate the effectiveness of this drug combination in advanced GIST. MEK162 inhibits a protein called MEK1/2, which drives cancer growth. Both imatinib and MEK162 are taken orally (by mouth).