Tositumomab

Diagram of the molecular structure of Tositumomab
Brand name: Bexxar®
IUPAC: Humanized anti-VEGF antibody
FDA approval: Yes
Manufacturer Link
Usage:

Tositumomab (Bexxar®) is a monoclonalDerived from a single source. In the context of cancer, the term is used in two ways: 1) to refer to the fact that tumors arise from a single damaged cell and 2) to describe the antibodies used in the treatment of cancer. antibodyAntibody molecules tightly bind to their targets (usually proteins) with great specificity. Antibody binding alerts the immune system to target the bound molecule for destruction. Specific antibodies can be made in the laboratory. treatment targeted at the CD20 antigenAny substance capable of being recognized by the immune system. Recognition of such a substance leads to the generation of an immune response.. Tositumomab is used in the treatment of relapsed or refractory (treatment resistant) Non-Hodgkin's LymphomaA cancer arising in the lymphatic system. The white blood cells affected are part of the body's immune system. The lymphatic system is a large network of vessels that carry fluid and cells of the immune system around the body. Lymph nodes are regional collection centers in the lymphatic system. See also, 'lymphatic system'.. Tositumomab is administered as 2 sets of infusions, a non-radioactiveSome elements (atoms) are not stable. The breakdown of these elements leads to the release of energy that is called radiation. The form of the energy (radiation) may differ between different unstable elements. Radiation from the breakdown of radioactive elements is damaging to cells and their genes. Cancer cells do not respond in a normal fashion to DNA damage and may be sensitive to killing by the radiation emitted from radioactive elements. antibody and then a radioactive antibody. 1

Mechanism:

This treatment is different from most antibodyAntibody molecules tightly bind to their targets (usually proteins) with great specificity. Antibody binding alerts the immune system to target the bound molecule for destruction. Specific antibodies can be made in the laboratory. -based treatmets. In this case, the antibody has been permanently linked to a radioactiveSome elements (atoms) are not stable. The breakdown of these elements leads to the release of energy that is called radiation. The form of the energy (radiation) may differ between different unstable elements. Radiation from the breakdown of radioactive elements is damaging to cells and their genes. Cancer cells do not respond in a normal fashion to DNA damage and may be sensitive to killing by the radiation emitted from radioactive elements. form of iodine (I131). The antibody is used to deliver the radioactive iodine to cancer cells which are then destroyed by the radiationIn cancer biology: A cancer treatment in which high energy beams are used to kill cancer cells. Radiation can also cause genetic damage that can lead to cancer. As an example, skin cancer is believed to be greatly increased by exposure to ultraviolet (UV) radiation from the sun.. This form of treatment is termed radioimmunotherapy. Note that the image shown is a general structure of an antibody. There are four proteins bound together in a 'Y' shape. The two top tips of the Y are where the antibody binds with its target. This means that each antibody molecule can bind to two identical target regions.1

Side effects:

The most common side effect associated with tositumomab treatment is lowered blood cell count. Other common side effects are mostly infusion-related, and they include: weakness, fever, nausea, infection, cough. Severe allergic reactions may also occur.1

Contraindications:

Patients should not become pregnant while undergoing tositumomab therapy and therapy should not be given before pregnancy is ruled out. Contraception should be used by males and females during and 12 months after treatment has ended.  Patients who have already received murine proteins and may have mounted an anti-mouse immune response are at a higher risk for a reaction of this sort. In some patients hypothyroidism (reduced thyroid gland function) may occur. For this reason thyroid blocking agents must be administered with tositumomab. Treatment and screening for hypothyroidism should continue on an annual basis after treatment ends. Because this therapy includes a radioactiveSome elements (atoms) are not stable. The breakdown of these elements leads to the release of energy that is called radiation. The form of the energy (radiation) may differ between different unstable elements. Radiation from the breakdown of radioactive elements is damaging to cells and their genes. Cancer cells do not respond in a normal fashion to DNA damage and may be sensitive to killing by the radiation emitted from radioactive elements. material that is inside the body for some period of time, patients should be given special instructions and precautions to prevent harm to any other person.1

  • 1. Bexxar Prescribing Information. GlaxoSmithKline and Corixa Corporation. 2013. [https://www.gsksource.com/pharma/content/dam/GlaxoSmithKline/US/en/Prescribing_Information/Bexxar/pdf/BEXXAR.PDF]
  • 2.a. b. c. Chu, E., & DeVita, V. T. (2015). Physicians' cancer chemotherapy drug manual 2015. Burlington, MA: Jones & Bartlett Learning.