RecruitingPhase 2Drug trialKQB198 in Combination With Imatinib in Participants With Advanced/Metastatic GIST in 1st Line SettingThis study will test an experimental drug called KQB198 in combination with imatinib. The goal is to determine if this combination is safe and tolerable and assess how effective the combination is at treating GIST. Imatinib has been approved by the FDA for the treatment of different types of cancer including GIST.