Trial of Ixazomib for Kaposi Sarcoma

PRIMARY OBJECTIVE: I. Determine the overall response rate of ixazomib in participants with Kaposi sarcoma. SECONDARY OBJECTIVES: I. Determine safety and tolerability of ixazomib. II. Assess changes in Kaposi-sarcoma associated herpesvirus (KSHV) viral load (VL) by ixazomib. III. Correlate changes in KSHV VL with tumor response. IV. For human immunodeficiency virus (HIV)-positive participants, assess changes in CD4 counts and HIV viral load. EXPLORATORY OBJECTIVE: I. Assess changes in quality of life during ixazomib therapy. OUTLINE: Patients receive ixazomib orally (PO) on days 1, 8, and 15. Treatment repeats every 28 days for up to 12 cycles in the absence of disease progression or unacceptable toxicity. Patients with complete or partial response may continue treatment for an additional 12 cycles in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 4 weeks, then periodically for up to 2 years.