Current status of animal radioimmunotherapy

Progress in animal radioimmunotherapy has been reviewed by highlighting 22 successful experiments using human xenografts in rodent models. Significant tumor growth delay has been observed in all experiments with five groups reporting tumor control 100 days post-tumor implantation. The radiobiological significance of these experiments is analyzed through a proposed framework for the comparison of radioimmunotherapy to external beam therapy in both animals and humans. The limits of applicability of animal modeling to the clinical setting are evaluated in terms of intrinsic radiosensitivity, tumor volume effects, tumor bed effects, and the host defense mechanism. A generalized strategy for the development of clinical radioimmunotherapy is proposed based on utilization of radioimmunotherapy as a boost therapy in combination with external beam radiation.