Radioimmunoconjugates (radiolabeled antibodies and
radiolabeled proteins) are a class of conjugates used primarily for
cancer/tumor imaging and therapy. They
consist of either a targeting antibody / protein directly labeled with a
radionuclide (radioisotope) such as iodine 131, or a targeting antibody /
protein conjugated to a radionuclide chelator (e.g., CHX-A, DOTA) and then
indirectly labeled with a radionuclide, e.g., indium 111 or yttrium 90 via the
chelator. Radioimmunoconjugates offer
radio-immunodiagnostic solutions at low doses of radionuclide, but can also
provide radioimmunotherapy at high doses of the radionuclide.Example of FDA approved radioimmunoconjugates
include Zevalin® and Bexxar..