Study of IDE397 in Participants With Solid Tumors Harboring MTAP Deletion

Inclusion Criteria:

• Participant must be at least 18 years of age
• Advanced or metastatic solid tumor that has progressed on at least one prior line of treatment or is intolerant to additional effective standard therapy
• Have evidence of homozygous loss of MTAP or MTAP deletion at the DNA or protein level in the participant's tumor tissue
• Measurable disease
• ECOG performance status <= 1 or 2
• Adequate organ function
• Able to swallow and retain orally administered study treatment
• Able to comply with contraceptive/barrier requirements

Exclusion Criteria:

• Known symptomatic brain metastases that are not neurologically stable for 3 months
• Known primary CNS malignancy
• Current active liver or biliary disease
• Active inflammatory gastrointestinal disease, chronic diarrhea, known diverticular disease or previous gastric resection or lap band surgery
• Impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of IDE397
• Active, uncontrolled infection including hepatitis B virus, hepatitis C virus, human immunodeficiency virus, or acquired immunodeficiency syndrome related illness
• Baseline 12 lead ECG that demonstrates clinically relevant abnormalities
• Clinically significant cardiac events 6 months before study entry
• Uncontrolled hypertension despite optimal medical therapy
• Previous treatment with a MAT2A inhibitor and / or PRMT inhibitor
• Major surgery within 4 weeks prior to C1D1
• Radiation therapy within 4 weeks prior to C1D1
• Systemic anti-cancer therapy (non-monoclonal antibody) within 4 weeks prior to study entry or within 28 days prior to study entry for an antibody based agent(s) or 5 half-lives (whichever is shorter)
• Have received radioimmunotherapy less than 6 weeks before the first dose of IDE397
• Have received treatment with a therapeutic antibody less than 4 weeks before the first dose of IDE397
• Have received treatment with an investigational small molecule less than 2 weeks before the first dose of IDE397
• Prior irradiation to >25% of the bone marrow
• Current use or anticipated need for food or drugs that are known strong CYP3A4/5 inhibitors
• Current use or anticipated need for food or drugs that are known strong CYP3A4/5 inducers
• Received an investigational product within 28 days prior to first dose of IDE-397 or 5 half-lives (whichever is shorter)
• Exposure to more than 4 investigational medicinal products within 12 months prior to C1D1
• Known or suspected hypersensitivity to IDE397/excipients or components