BACKGROUND:~Bexxar (Tositumomab and Iodine I 131 Tositumomab) is a radioimmunoconjugate with demonstrated anti-lymphoma effects. This drug is indicated for the treatment of patients with CD20 positive, relapsed or refractory, low grade, follicular, or transformed non-Hodgkin's lymphoma, including patients with Rituximab-refractory non-Hodgkin's lymphoma. Bexxar has been used in several Phase I and II transplant trials either alone or in combination with high-dose chemotherapy for the treatment of relapsed non-Hodgkin's lymphoma. The Phase I and II trials combining Bexxar with BEAM and autologous hematopoietic stem cell transplantation demonstrated promising early results with 80% event-free survival in relapsed chemosensitive diffuse large B-cell non-Hodgkin's lymphoma patients. The administration of Rituxan to the mobilization and conditioning regimen is now the standard of care at most transplant centers. Therefore, the primary endpoint of this study will be to compare progression-free survival after autologous hematopoietic stem cell transplantation for chemotherapy-sensitive diffuse large B-cell lymphoma using Rituxan/BEAM versus Bexxar/BEAM for pre-transplant conditioning.~DESIGN NARRATIVE:~All patients will receive induction or salvage chemotherapy as indicated by their clinical circumstance to achieve at least a partial response (as defined in the protocol). There must be 20% or less bone marrow involvement after their most recent salvage therapy.~Mobilization therapy may be employed per institutional guidelines, but all patients must receive one dose of rituxan (375 mg/m^2) at least within 4 weeks of actual stem cell apheresis. Patients must have an adequate autograft (target of at least 2.0 X 10^6 CD34+ cells/kg; minimum of more than 1.5 X 106 CD34+ cells/kg) to be eligible for the protocol. Eligible patients will be randomized to receive either: 1) Rituxan plus BEAM, with Rituxan 375 mg/m^2 IV Days -19 and -12, Carmustine (BCNU) 300 mg/m^2 Day -6, Etoposide 100 mg/m^2 Days -5 to -2, Cytarabine 100 mg/m^2 Days -5 to -2, and Melphalan 140 mg/m^2 Day -1 followed by ASCT; or, 2) Bexxar/BEAM with the dosimetric dose of 5 mCi Bexxar on Day -19 and the therapeutic dose calculated to administer 75 cGy total body dose (TBD) on Day -12. Patients will then receive BCNU 300 mg/m^2 Day -6, Etoposide 100 mg/m^2 Days -5 to -2, Cytarabine 100 mg/m^2 Days -5 to -2, and Melphalan 140 mg/m^2 Day -1 followed by ASCT.~Patients will be followed for 2 years post-transplant. Survival data, hematopoiesis data, incidence of infection, mucositis assessment data, immune reconstitution data, and toxicity data will be recorded and reported periodically to the BMT CTN Data Coordinating Center (DCC).
This study is designed as a Phase III, multicenter trial, comparing progression-free survival (PFS) after autologous hematopoietic stem cell transplantation using a standard Rituxan plus BEAM transplant regimen versus a regimen adding Bexxar to BEAM.