131I-Tositumomab is a radiolabeled anti-CD20 antibody launched in 2003 under the name Bexxar for the treatment of non-Hodgkin lymphoma (NHL). Bexxar has been approved in the US since 2003 and Canada since 2005. Bexxar was never launched in Europe.

Bexxar was discontinued and marketing approval withdrawn on February 20, 2014 following the failure to demonstrate in 2011 a clinical benefit over CHOP chemotherapy plus Rituxan (rituximab) in patients with newly diagnosed follicular NHL. This resulted in the decline in usage.

131I-Tositumomab is indicated for the treatment of patients with CD20 antigen-expressing relapsed or refractory, low-grade, follicular or transformed NHL, including patients with Rituximab-refractory non-Hodgkin’s lymphoma. It seems that private investors are considering relaunching this drug, however, no more information is available at this time, probably as a consequence of a lack of funding.

Target/Mechanism: CD20

Carrier/Ligand: Tositumomab

Radiation Type: beta electrons (β)