Tositumomab and I-131 (Bexxar)
Note: GlaxoSmithKline has discontinued the manufacture and sale of the BEXXAR therapeutic regimen (tositumomab and iodine I 131 tositumomab) as of February 2014.
Class/mechanism: Radioimmunotherapy; treatment regimen that includes two separate steps: first, a dosimetric dose with an anti-CD20 antibody (tositumomab) alone, and second, a therapeutic dose with tositumomab bound to a radioactive isotope, iodone-131 (I-131). Tositumomab binds to the extracellular domain of the CD20 molecule expressed on B-cells and may induce complement-dependent cytotoxicity (CDC) and/or antibody-dependent cell mediated cytotoxicity (ADCC). The I-131 that is bound to tositumomab emits ionizing radiation, leading to cell death.
Extravasation: no information
For conciseness and simplicity, HemOnc.org currently will focus on treatment regimens and not list information such as: renal/hepatic dose adjustments, metabolism (including CYP450), excretion, monitoring parameters (although this will be considered for checklists), or manufacturer. Instead, for the most current information, please refer to your preferred pharmacopeias such as Micromedex, Lexicomp, UpToDate (courtesy of Lexicomp), or the prescribing information.
Diseases for which it was used
Patient drug information
- Tositumomab and I-131 (Bexxar) patient drug information (Chemocare)
- Tositumomab and I-131 (Bexxar) patient drug information (UpToDate)
History of changes in FDA indication - PARTIALLY WITHDRAWN
- 2003-06-27: Granted accelerated approval for the treatment of patients with CD20 positive, follicular, non-Hodgkin's lymphoma, with and without transformation, whose disease is refractory to Rituximab (Rituxan) and has relapsed following chemotherapy. (Based on CP-97-012 & RIT-II-004)
- 2004-12-22: Accelerated approval for patients with relapsed or refractory, low grade, follicular or transformed CD20 positive non-Hodgkin's lymphoma who have not received Rituximab (Rituxan). (No supporting studies are cited)
- 2013-10-23: Approval for rituximab-naive patients withdrawn. (failure to complete confirmatory study)
Also known as
- Generic names: tositumomab and I 131 tositumomab, tositumomab and iodine-131 tositumomab
- Brand name: Bexxar