KQB198 in Combination With Imatinib in Participants With Advanced/Metastatic GIST in 1st Line Setting

Inclusion Criteria

All Participants:

• Unresectable or metastatic disease
• Tissue confirmation of GIST
• Valid results from local testing of blood or tumor tissue documenting the presence of a KIT mutation (must not have exon 9 mutation) or PDGFRA mutation (must not have PDGFRA D842V).
• Measurable disease per RECIST v1.1.
• Patients must be in 1st line of treatment for advanced or metastatic disease. Prior imatinib is allowed in adjuvant or neoadjuvant setting, as long as imatinib was stopped over 1 year ago.
• Adequate organ function and performance status

Exclusion Criteria

Participants are excluded from the study if any of the following criteria apply:

• Unable to swallow or GI condition that prevents absorption.
• Other active malignancies within the last 2 years.
• History of hypersensitivity to any component of KQB198 or imatinib.