Iodine I 131 Tositumomab and Fludarabine Phosphate in Treating Older Patients Who Are Undergoing an Autologous or Syngeneic Stem Cell Transplant for Relapsed or Refractory Non-Hodgkin's Lymphoma

PRIMARY OBJECTIVES:

I. To estimate the maximally tolerated dose of fludarabine that can be combined with
131I-anti-CD20 delivering =< 27Gy to critical normal organs followed by autologous or
syngeneic transplantation in patients >= 60 years of age with relapsed B-NHL.

SECONDARY OBJECTIVES:

I. To assess the overall and progression-free survival of the above regimen in such
patients.

II. To evaluate the response rates of the above therapy. III. To evaluate the toxicity and
tolerability of the above therapy. IV. To evaluate the feasibility of delivering concurrent
high-dose RIT and chemotherapy.

OUTLINE: This is a dose-escalation study of fludarabine phosphate.

Patients receive a dosimetric dose of iodine I 131 tositumomab IV over 40-60 minutes on day
-24 followed by dosimetry periodically over the next 6 days. Patients then receive a
therapeutic dose of iodine I 131 tositumomab IV over 40-60 minutes on day -14. Patients also
receive fludarabine phosphate IV once daily on days -11 to -9 OR days -11 or -7. Patients
undergo autologous or syngeneic peripheral blood stem cell transplantation on day 0.

Patients with circulating lymphoma cells by peripheral smear receive tositumomab IV over 1
hour OR rituximab IV over 1 hour followed by tositumomab IV over 1 hour before the
dosimetric iodine I 131 tositumomab infusion.

After completion of study treatment, patients are followed at 1, 3, 6, and 12 months and
then annually thereafter.