A Study of Ziftomenib, an Oral Menin Inhibitor, in Combination With Imatinib in Patients With Advanced Gastrointestinal Stromal Tumors (GIST)

Inclusion Criteria

• Documented diagnosis of advanced or metastatic KIT mutant GIST.
• Documented disease progression on imatinib therapy as current or prior treatment.
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) of ≤2 at screening.
• At least 1 measurable lesion per mRECIST.
• Negative pregnancy test for female patients of childbearing potential.
• Adequate organ function per protocol requirements.
• Resolution of all clinically significant toxicities from prior therapy to ≤Grade 1 (or patient baseline) within 1 week prior to the first dose of study drug.
• Participant, or legally authorized representative, must be able to understand and provide written informed consent prior to the first screening procedure. Key

Exclusion Criteria

• Diagnosis of non-KIT mutation or a T670X KIT mutation-driven GIST.
• History of prior or currently has cancer which has potential to interfere with obtaining study results.
• Received a prohibited medication, including investigational therapy, less than 14 days or within 5 drug half-lives prior to the first dose of study intervention.
• Active central nervous system metastases.
• Uncontrolled intercurrent illness, including, but not limited to protocol defined cardiac disease.
• Mean corrected QT interval (QTcF) greater than 470ms.
• Left ventricular ejection fraction (LVEF) <50%.
• Major surgery within 2 weeks prior to the first dose of study intervention.
• Is pregnant or lactating.
• Gastrointestinal abnormalities that may impact taking study intervention by mouth.
• Actively bleeding, excluding hemorrhoidal or gum bleeding.