Tazemetostat in Treating Patients With Metastatic or Unresectable Solid Tumors or B-Cell Lymphomas With Liver Dysfunction

PRIMARY OBJECTIVES: I. To determine safety, tolerability and recommended phase 2 dose (RP2D) of tazemetostat in patients with varying degrees of hepatic dysfunction. SECONDARY OBJECTIVES: I. To assess the pharmacokinetics (PK) profiles of tazemetostat in patients with varying degrees of hepatic dysfunction. II. To observe preliminary antitumor activity of tazemetostat in this population, especially in tumors with aberrations in EZH2 or SWI/SNF complex pathways. OUTLINE: This is a dose escalation study. Patients receive tazemetostat orally (PO) twice daily (BID) on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 4 weeks.