Bexxar is a monoclonal antibody that is linked with radioactive iodine I-131. Monoclonal antibodies are made to target and destroy only certain cells in the body. This may help to protect healthy cells from damage. Bexxar is used to treat certain forms of non-Hodgkin's lymphoma. It is usually given after other medications have been tried without successful treatment. Bexxar may also be used for purposes not listed in this medication guide.