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

Eligibility 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.
• * 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.