tositumomab + iodine I-131

A radioimmunotherapy regimen combining the anti-CD20 monoclonal antibody tositumomab with the beta- and gamma-emitting radiopharmaceutical iodine-131 to deliver targeted radiotherapy to CD20-positive B cells in non-Hodgkin lymphoma. The antibody binds CD20 on B cells and can mediate immune effector functions, while the iodine-131 conjugate delivers cytotoxic ionizing radiation to bound cells and nearby tumor cells. It was FDA-approved as Bexxar for certain relapsed/refractory CD20-positive follicular non-Hodgkin lymphoma, with treatment administered in a two-step protocol (dosimetric step followed 7–14 days later by the therapeutic step). Manufacture and sale were discontinued in 2014.

Brand names

Bexxar

Other names

tositumomab and I-131iodine I 131 tositumomabtositumomab I-131