Monoclonal Antibody Therapy and Peripheral Stem Cell Transplant in Treating Patients With Non-Hodgkin's Lymphoma

PRIMARY OBJECTIVES: I. To determine the maximum tolerated dose of IDEC-Y2B8 when administered with rituximab in vivo purging and autologous stem cell rescue. II. To obtain correlative laboratory data of in vivo purging with rituximab in patients with 0-35% marrow involvement. OUTLINE: This is a multicenter, dose-escalation study of yttrium Y 90 ibritumomab tiuxetan (IDEC-Y2B8). PART I: Patients receive rituximab IV on days 1, 8, 15, and 22 and cyclophosphamide IV over 1 hour on day 25. Filgrastim (G-CSF) is administered subcutaneously (SC) daily beginning on day 26 and continuing until autologous peripheral blood stem cells (PBSC) are harvested. PART II: Beginning 4-6 weeks after completion of the fourth rituximab infusion, patients receive indium In 111 ibritumomab tiuxetan IV over 10 minutes on day 1 followed by dosimetry imaging on days 1, 2, 4, and 7. Patients then receive IDEC-Y2B8 IV over 10 minutes once between days 8-15. The initial 3 patients receive the same dose of IDEC-Y2B8 and then subsequent cohorts of 3-5 patients receive escalating doses of IDEC-Y2B8 until the maximum tolerated dose is determined. PART III: All patients undergo PBSC transplantation (PBSCT) beginning after residual bone marrow radioactivity resolves. G-CSF is administered SC beginning 1 day after PBSCT and continuing until blood counts recover. Patients are followed every 3 months for 1 year and then every 6 months thereafter.