Belinostat and Yttrium Y 90 Ibritumomab Tiuxetan in Patients W/Relapsed Aggressive B-Cell NHL

PRIMARY OBJECTIVES: I. To document the complete response rate and overall response for patients with relapsed aggressive high-risk non-Hodgkin's lymphoma treated with two cycles PXD-101 followed by one cycle of Zevalin. SECONDARY OBJECTIVES: I. To estimate 2-year progression-free survival in patients with relapsed aggressive high-risk non-Hodgkin's lymphoma treated with two cycles PXD-101 followed by one cycle of Zevalin. II. To evaluate the toxicity of two cycles PXD-101 and one cycle of Zevalin in patients with relapsed aggressive high-risk non-Hodgkin's lymphoma. OUTLINE: Patients receive belinostat intravenously (IV) over 30-60 minutes on days 1-5. Treatment with belinostat repeats every 21 days for 2 courses. Patients then receive rituximab IV on days 1 and either 7, 8, or 9, and yttrium Y 90 ibritumomab tiuxetan IV over 10 minutes on day 50. Treatment continues in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 2 years and then every 6 months for 3 years.