Radioimmunotherapy with tositumomab and iodine-131 tositumomab for non-Hodgkin’s lymphoma

With the success of targeted monoclonal antibody therapy in non-Hodgkin's lymphoma, attempts were made to further improve efficacy through the addition of a radioisotope. A goal of radioimmunotherapy is to utilize the monoclonal antibody to deliver radiation to a tumor bed with relatively limited toxicity to the surrounding normal tissues. I-131 Tositumomab is an iodine-131 labeled anti-CD20 murine IgG2a monoclonal antibody and is one of two FDA-approved radioimmunotherapeutic drugs for patients with non-Hodgkin's lymphoma (NHL). For more than a decade now, radiolabeled tositumomab has principally been evaluated in low-grade and transformed low-grade NHL patients with proven efficacy in both the up-front and salvage settings. Studies have included its use as a single agent, in combination with chemotherapy and as part of a conditioning regimen for autologous stem cell transplantation. These data suggest that this agent has an important role in the treatment of patients with B cell lymphoma.