Radioimmunotherapy combines radiotherapy with monoclonal antibody therapy. Zevalin® and Bexxar® are the only two radioimmunotherapy treatments approved in the U.S. The FDA has approved them for treatment of specific types of NHL.
How Does Radioimmunotherapy Work?
Cancer cells, like healthy cells, have receptors on their surface (antigens) that are specific to certain proteins.
Protein molecules that attach to these specific receptors are cloned in the lab and labeled with a radiation-emitting isotope (radionuclide). When injected into the patient, they seek out and attach to the cancer cells, killing most of the cancer cells with radiation.
The major advantages to radioimmunotherapy are short treatment time and reduced side effects for most patients. This is largely due to the targeted nature of the treatment. The radiation decays slowly, so it continues to attack the cancer over time after a single dose. It's not quite as simple as that, however. Other drugs and tests must be administered to prepare the patient for treatment with the radiolabeled monoclonal antibodies. For example, The Zevalin regimen lasts 7-9 days.
The radioactive treatment remains concentrated in the area of the disease, thus limiting the extent of many typical lymphoma treatment side effects. Patients do not usually experience hair loss or long bouts of nausea and vomiting.
Disadvantages and Side Effects
Radionuclides may also kills healthy cells, but, because the radiation concentrates in the cancer cells, the damage will be mostly confined to the general location of the disease.
Radioimmunotherapy is not a standalone treatment but is part of a treatment regimen. Patients may experience serious side effects from the treatments that precede the radioimmunotherapy.
Some patients experience nausea and vomiting, but to a lesser degree than with chemotherapy.
Diabetics may experience serious glucose level misreading during treatment if they are using GDH-PQQ test strips.
Patients often experience fever, chills, low blood pressure, and diarrhea.
Radioimmunotherapy affects bone marrow and decreases blood cell counts. People with compromised autoimmune systems and bone marrow disorders are not good candidates for radiolabeled monoclonal antibodies.
Pregnant women are not good candidates for radioimmunotherapy.
The extent of side effects can be influenced by previous treatments such as chemotherapy.
Other side effects are detailed at the Zevalin® and Bexxar® web sites.