Radioimmunotherapy: is avidin-biotin pretargeting the preferred choice among pretargeting methods?

Excerpt

The major objective of cancer radioimmunotherapy (RIT) is to enhance the effectiveness of the drug by concentrating it at the tumour site and simultaneously achieving fewer toxic side-effects to normal organs. Tumour targeting was successful with large long-circulating radiolabelled monoclonal antibodies (MoAbs), but high radiation doses to normal organs, especially liver and bone marrow, soon appeared as a significant problem. Therefore the success of conventional RIT (radioactivity directly attached to MoAbs) has been restricted to leukaemias and lymphomas, in which the tumours are radiosensitive and the tumour cells are relatively accessible. Recent reports of clinical success in the treatment of aggressive non-Hodgkin's lymphoma (NHL) by using commercially available yttrium-90 labelled anti-CD20 MoAb have had a tremendous impact on the credibility of RIT for cancer therapy, almost 30 years after the discovery of the hybridoma technology by Kohler and Milstein in 1975. …