S0433 Iodine I 131 Tositumomab, Rituximab, and Combination Chemotherapy in Treating Older Patients With Stage II, Stage III, or Stage IV Non-Hodgkin’s Lymphoma

OBJECTIVES:

Determine the 2-year progression-free survival of older patients with previously untreated bulky stage II or stage III or IV diffuse large B-cell non-Hodgkin's lymphoma treated with iodine I 131 tositumomab in combination with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone.
Determine the response rate (partial response, complete unconfirmed response, and complete response) in patients treated with this regimen.
Determine the 2-year progression-free survival and response rate (partial response, complete unconfirmed response, and complete response) in B-cell lymphoma 2 (BCL-2) positive patients treated with this regimen.

OUTLINE: This is a multicenter study.

Rituximab and chemotherapy: Patients receive R-CHOP comprising rituximab IV over 6 hours; cyclophosphamide IV over 15-45 minutes; doxorubicin IV over 5-20 minutes; and vincristine IV over 5-15 minutes on day 1 and oral prednisone on days 1-5. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. Patients then undergo a restaging evaluation. Patients without progressive disease receive CHOP chemotherapy comprising cyclophosphamide, doxorubicin, vincristine, and prednisone as outlined above. Treatment with CHOP chemotherapy repeats every 21 days for 2 courses.
Radiolabeled monoclonal antibody therapy: Approximately 4-8 weeks after completion of chemotherapy, patients receive tositumomab IV over 1 hour followed by a dosimetric dose of iodine I 131 tositumomab IV over 20 minutes. Patients then undergo gamma scans over a 1-week period in order to determine the correct treatment dose of iodine I 131 tositumomab. No more than 2 weeks after administration of the dosimetric dose, patients receive tositumomab IV over 1 hour followed by a treatment dose of iodine I 131 tositumomab IV over 20 minutes.

After completion of study treatment, patients are followed periodically for up to 5 years.

PROJECTED ACCRUAL: A total of 80 patients will be accrued for this study within 15 months.