Radio immunotherapy (RIT) uses an antibody labeled with a radionuclide to deliver cytotoxic radiation to a target cell. In cancer therapy, an antibody with specificity for a tumor-associated antigen is used to deliver a lethal dose of radiation to the tumor cells. The ability for the antibody to specifically bind to a tumor-associated antigen increases the dose delivered to the tumor cells while decreasing the dose to normal tissues.
A set of radioimmunotherapy drugs that rely upon an alpha particle-emitting isotope (e.g., Bi-213 or, preferably, Ac-225), rather than a beta emitter, as the killing source of radiation is being developed. The most developed drug is directed to treating acute myeloid leukemia and is in patient clinical trials (as of the fourth quarter of 2010). Also, in 2015: FF-21101(90Y) is a monoclonal antibody against P-cadherin radio labeled with Yttrium-90.
Other types of cancer for which RIT has therapeutic potential include prostate cancer, metastatic melanoma, ovarian cancer, neoplastic meningitis, leukemia, high-grade brain glioma, and metastatic colorectal cancer. other recently uses among treatment of pemphigus, lichen planus and other immune disorder are also reported with success rate of 18 out of 21 cases of refractory disease.