Perspectives on cancer therapy with radiolabeled monoclonal antibodies.

With the approval of 2 radiolabeled antibody products for the treatment of non-Hodgkin's lymphoma (NHL), radioimmunotherapy (RIT) has finally come of age as a new therapeutic modality, exemplifying the collaboration of multiple disciplines, including immunology, radiochemistry, radiation medicine, medical oncology, and nuclear medicine. Despite the many challenges that this new therapy discipline has encountered, there is growing evidence that RIT can have a significant impact on the treatment of cancer. Although follicular NHL is currently the only indication in which RIT has been proven to be effective, clinical trials are showing usefulness in other forms of NHL as well as in other hematologic neoplasms. However, the treatment of solid tumors remains a formidable challenge, because the doses shown to be effective in hematologic tumors are insufficient in the more common epithelial cancers. Nevertheless, there has been progress in locoregional applications and in the treatment of minimal residual disease. There is also optimism that pretargeting procedures, including new molecular constructs and targets, will improve the delivery of radioactivity to tumors, do so with less hematologic toxicity, and become the next generation of RIT.