OBJECTIVES:

• Determine the maximum tolerated dose of yttrium Y 90 ibritumomab tiuxetan, in terms of absorbed radiation to critical organs, when administered with high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation in patients with relapsed or refractory B-cell non-Hodgkin's lymphoma.
• Determine whether the residual radioactivity detected at the time of stem cell reinfusion affects the reinfused cells and delays engraftment in patients treated with this regimen.
• Determine the duration of response and survival of patients treated with this regimen.

OUTLINE: This is a dose-escalation study of yttrium Y 90 ibritumomab tiuxetan (IDEC-Y2B8).

• Radioimmunotherapy: Patients receive rituximab IV followed by indium In 111 ibritumomab tiuxetan (for imaging) IV over 10 minutes on day -22. Patients then receive rituximab IV and IDEC-Y2B8 IV over 10 minutes on day -14.

Cohorts of 3-6 patients receive escalating doses of IDEC-Y2B8 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 3 of 6 patients experience dose-limiting toxicity.

• High-dose conditioning regimen: Patients receive BEAM chemotherapy comprising carmustine IV over 2 hours on day -6, etoposide IV over 2 hours twice daily and cytarabine IV over 1 hour twice daily on days -5 to -2, and melphalan IV over 1 hour on day -1.
• Autologous stem cell transplantation: Autologous peripheral blood stem cells are reinfused on day 0. Patients receive filgrastim (G-CSF) subcutaneously daily beginning on day 0 and continuing until blood counts recover.

Patients are followed at 30 days, 3 and 6 months, and then annually for 5 years.

PROJECTED ACCRUAL: A maximum of 42 patients will be accrued for this study.