(Peak) A Phase 3 Randomized Trial of CGT9486+Sunitinib vs. Sunitinib in Subjects With Gastrointestinal Stromal Tumors

Key Inclusion Criteria:

• Histologically confirmed locally advanced, metastatic, and/or unresectable GIST. Molecular pathology report must be available for Part 2; if molecular pathology report is unavailable or inadequate, an archival or fresh tumor tissue sample will be required to evaluate mutational status prior to randomization. (GIST 1L Substudy: must have documented mutation in KIT Exon 9 with an available molecular pathology report; archival or fresh tumor tissue sample will be required)
• Documented disease progression on or intolerance to imatinib (Part 1a, Part 1b, Part 2, DDI Substudy)
• Subjects must have received the following treatment:

• DDI Substudy/Part 1a: Treatment with ≥1 prior lines of therapy for GIST
• Part 1b: Treatment with ≥2 prior TKI for GISTs
• Part 2: Prior treatment with imatinib only
• GIST 1L Substudy: No prior systemic therapy for GIST including adjuvant therapy. Exception: up to 10 subjects with ongoing imatinib therapy of ≤4 weeks
• Have at least 1 measurable lesion according to mRECIST v1.1 (Part1a, Part 1b, Part 2, GIST 1L Substudy)
• Eastern Cooperative Oncology Group (ECOG) Status

• 0 to 2 (Part 1a, Part 1b, Part 2, DDI Substudy)
• 0 to 1 (GIST 1L Substudy)
• Have clinically acceptable local laboratory screening results (clinical chemistry and hematology) within certain limits

Key Exclusion Criteria:

• Known Platelet-Derived Growth Factor Receptor (PDGFR) driving mutations or known succinate dehydrogenase deficiency (Part 1a, Part 1b, Part 2, DDI Substudy)
• Clinically significant cardiac disease
• Major surgeries (eg, abdominal laparotomy) within 4 weeks of the first dose of study drug (Part 1a, Part 1b, Part 2, DDI Substudy)
• Gastrointestinal abnormalities including, but not limited to, significant nausea and vomiting, malabsorption, external biliary shunt, or significant bowel resection that would preclude adequate absorption
• Any active bleeding excluding hemorrhoidal or gum bleeding
• Seropositive for HIV 1 or 2, or positive for hepatitis B surface antigen or hepatitis C virus (HCV) antibody.
• Active, uncontrolled, systemic bacterial, fungal, or viral infections at Screening
• Received strong CYP3A4 inhibitors or inducers (Part 1a, Part 1b, Part 2, DDI Substudy)
• Received sunitinib within 3 weeks (Part 1a, Part 1b, DDI Substudy)