PARENT SESSION
8:00 AM to 8:50 AM
Tuesday, April 23, 2002
Refresher Course 18
The Current Status of Radioimmunotherapy
Room: Nevada 1-2
Knox, Susan³³Dept of Radiation Oncology, Stanford, CA

(RC18) The current status of radioimmunotherapy.

Knox, Susan^*,1, ¹ Stanford University Medical Center, Stanford, California

ABSTRACT-
Radioimmunotherapy (RIT) is a promising new therapy for the treatment of a variety of malignancies. General principles of RIT will be discussed, including important considerations in the selection of monoclonal antibodies (MAb) and radionuclides for RIT. Results of clinical trials using RIT will be summarized. The results from many of these trials are promising, especially for the treatment of lymphohematopoietic malignancies, in which high response rates with a number of durable responses have been reported. However, results of most solid tumor RIT trials have been less successful, largely because of low antibody uptake by tumor resulting in subtherapeutic tumor doses, as well as the relative radioresistance of solid tumors. RIT is generally well tolerated, with the primary toxicity being transient reversible myelosuppression in most nonmyeloablative studies. Approaches for increasing the therapeutic index of RIT will be reviewed and include optimization of a variety of biologic, chemical, and physical parameters. Chemical and physical properties of radionuclide and carrier conjugates must be carefully selected for given clinical situations in order to optimize dose deposition in targeted tumor. Advances in DNA technology have made it possible to create immunoglobulin fragments and constructs for specific functions that have desired antigen-binding specificities, affinities, and other characteristics. Experimental approaches for increasing the therapeutic index of RIT will be discussed and include pretargeting, the use of biological response modifiers, gene transfer techniques to increase target receptor expression, and the use of RIT in combination with radiosensitizers, chemotherapy, XRT, or gene therapy.

KEYWORDS: radioimmunotherapy, antibodies, targeted therapy, cancer treatment