Yttrium Y 90 Ibritumomab Tiuxetan in Treating Patients With Waldenstrom's Macroglobulinemia

OBJECTIVES: * Determine the maximum tolerated dose of yttrium Y 90 ibritumomab tiuxetan in patients with Waldenstrom's macroglobulinemia. * Determine, preliminarily, the response of patients treated with this drug. OUTLINE: This is a multicenter, dose-escalation study of yttrium Y 90 ibritumomab tiuxetan (IDEC-Y2B8). Patients receive rituximab IV and indium In 111 ibritumomab tiuxetan (IDEC-In2B8) IV over 10 minutes on day 1. Patients then undergo gamma camera scans within 2-24 hours. Approximately 7-14 days after IDEC-In2B8, patients receive rituximab IV and IDEC-Y2B8 IV over 10 minutes. Treatment with IDEC-Y2B8 may repeat every 12 weeks in the absence of unacceptable toxicity or the achievement of a maximum cumulative dose. 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 6 patients experience dose-limiting toxicity. Patients are followed every 3 months for 4 years. PROJECTED ACCRUAL: A total of 3-24 patients will be accrued for this study.