Trial of Low-Dose Methotrexate and I 131 Tositumomab for Previously Untreated, Advanced-Stage, Follicular Lymphoma

"Iodine I 131 tositumomab (Bexxar) is a radioimmunotherapy (RIT) drug. RIT is a treatment strategy designed to target radiation specifically to cancer cells by attaching a radioactive atom to a monoclonal antibody, an immune system protein that binds to a particular protein. The Iodine I 131 tositumomab (Bexxar) therapeutic regimen is delivered in two sets of intravenous infusions given about 7 days apart. Nonradioactive Tositumomab is given before both the dosimetric infusion and the therapeutic infusion to improve distribution of these doses throughout the body."

Methotrexate is an antifolate drug. It interferes with cells' ability to copy their DNA. This mainly affects cells that are dividing frequently, such as immune system cells and cancer cells. Methotrexate will be used in this study to try to prevent the occurrence of HAMA by limiting your body's ability to produce anti mouse antibodies.