Radioimmunotherapy (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. By its nature, RIT requires a tumor cell to express an antigen that is unique to the neoplasm or is not accessible in normal cells.
History of available agents
|U.S. FDA approval||Name||Description|
|2002||Ibritumomab tiuxetan (Zevalin)||monoclonal antibody anti-CD20 conjugated to a molecule that chelates Yttrium-90.|
|2003||Iodine (131I) tositumomab (Bexxar)||links a molecule containing Iodine-131 to an anti-CD20 monoclonal antibody.
It was withdrawn in 2014.
These medications were the first agents of radioimmunotherapy, and they were approved for the treatment of refractory non-Hodgkins lymphoma. This means they are used in patients whose lymphoma is refractory to conventional chemotherapy and the monoclonal antibody rituximab.
Agents in clinical development
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).
Other applications (non-approved indications)
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.
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- FIbritumomab Tiuxetan (Zevalin™) Radioimmunotherapy of Non-Hodgkin’s Lymphoma
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- Tositumomab and Iodine I 131 Tositumomab - Product Approval Information - Licensing Action
- "Why Good Drugs Sometimes Fail: The Bexxar Story".
- Strategia Therapeutics Initiates a Phase 1 Clinical Trial of the Radioimmunotherapeutic “FF-21101" For FUJIFILM in Patients with Advanced Cancers
- A Phase 1 Dose-escalation Study of Radio- Labeled Antibody, FF-21101(90Y) for the Treatment of Advanced Cancer
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- Dadachova E, Nosanchuk JD, Shi L, Schweitzer AD, Frenkel A, Nosanchuk JS, and Casadevall A. Dead cells in melanoma tumors provide abundant antigen for targeted delivery of ionizing radiation by a monoclonal antibody to melanin. Proc Natl Acad Sci USA 2004;101: 14865-70.
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- Wong JY, Shibata S, Williams LE, Kwok CS, Liu A, Chu DZ, Yamauchi DM, Wilczynski S, Ikle DN, Wu AM, Yazaki PJ, Shively JE, Doroshow JH, Raubitschek AA. A Phase I trial of 90Y-anti-carcinoembryonic antigen chimeric T84.66 radioimmunotherapy with 5-fluorouracil in patients with metastatic colorectal cancer. Clin Cancer Res. 2003 Dec 1;9(16 Pt 1):5842-52.