131-iodine tositumomab

131-iodine tositumomab is a radiolabeled monoclonal antibody therapy comprised of a murine anti-CD20 monoclonal antibody (tositumomab) covalently bound to the radioactive isotope iodine-131. It was originally branded as Bexxar and primarily indicated for the treatment of CD20-positive, relapsed or refractory, low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma, particularly in patients whose disease had progressed during or after rituximab therapy. Its mechanism of action involves both immune-mediated effects and targeted radiotherapy: the antibody component binds to the CD20 antigen on B lymphocytes, inducing immune effector functions such as complement-dependent cytotoxicity (CDC) and/or antibody-dependent cell-mediated cytotoxicity (ADCC), and delivering targeted ionizing radiation (via I-131) to kill malignant B-cells. The product was approved as a personalized regimen involving dosimetric and therapeutic dosing steps, with individualized calculations of the radioactive dose to maximize tumor killing and minimize systemic exposure. The Bexxar regimen was discontinued in 2014 and is no longer marketed.[1][3][4][6][7]

Brand names

Bexxar

Other names

tositumomab and iodine I 131 tositumomabtositumomab/iodine I-131 tositumomabI-131 tositumomabI131 tositumomabI 131 tositumomabIodine-131 TositumomabIodine131 TositumomabIodine 131 Tositumomab