Inclusion Criteria

• Advanced solid malignancies or Non-Hodgkins lymphoma for which all standard therapeutic options considered useful have been exhausted
• Must have objective evidence of progressive disease on study entry
• Measureable Advanced solid malignancy disease as defined by RECIST 1.1
• Measureable non-Hodgkins lymphoma disease including target lesion(s) as defined by the Lugano Classification for initial evaluation and staging
• Must have a site of disease amenable to biopsy and be a candidate for biopsy
• Eastern Cooperative Oncology Group (ECOG) performance status of ≤1
• For dose expansion phase of KPT-9274 + niacin ER cohort only, NAPRT1 and IDH1 tumor status must be determined at the central laboratory prior to enrollment
• Life expectancy of ≥3 months

Exclusion Criteria

• Known central nervous system (CNS) disease or leptomeningeal involvement, regardless of response to prior therapy
• Major surgery within 4 weeks before C1D1
• Active infection with completion of therapeutic antibiotics, antivirals, or antifungals within one week prior to C1D1
  • Prophylactic antibiotics, antivirals or antifungals are permitted
• Known history of Human Immunodeficiency Virus (HIV)
  • HIV testing is not required as part of this study
• Known, active hepatitis A, B, or C infection or known to be positive for HCV RNA or HBsAg (HBV surface antigen)
• Significant diseased or obstructed gastrointestinal tract or uncontrolled vomiting or diarrhea that could interfere with the absorption of KPT-9274
• Active peptic ulcer disease or other active gastrointestinal bleeds