Radioimmunotherapy, using radiolabelled antibodies, is a treatment for non-Hodgkin's lymphoma that combines the ability of monoclonal antibodies to dock on B cells with the cell-damaging ability of localised radiotherapy.
Radiolabelled antibodies consist of tiny amounts of radioactive material attached to a monoclonal antibody, which circulates in the body until it locates and binds to the surface of B cells. Once the monoclonal antibody has attached to the B cell, the radioactive substance kills the diseased cell, and any nearby lymphoma cells that the monoclonal antibody cannot target.
These treatments, which include ibritumomab tiuxetan, are among the options that can be given to patients with relapsed indolent non-Hodgkin's lymphoma that no longer responds well to conventional chemotherapy and monoclonal antibody rituximab.
The risk of haematological side effects with radiolabelled antibodies is relatively high. These include anaemia and immunosuppression, which can result in severe infections, as well as more minor reactions such as chills, fever, throat irritation and nausea. In addition, patients can suffer from a condition called thrombocytopenia, or low numbers of platelets in the blood. For more information, see Symptom management. There are also concerns over long term risks of secondary malignancies as with every type of radiation. However, there is currently insufficient evidence for the long term risks of radioimmunotherapy.
As the administration of radiolabelled antibodies involves radioactive material, it can be quite laborious, requiring the combined efforts of haematologists, nuclear physicists, nuclear medicine clinicians, and others to coordinate the delivery of the drug.