Development and evaluation of copper-67 and samarium-153 labeled conjugates for tumor radioimmunotherapy

Copper-67 and samarium-153 are two of the most attractive radionuclides for radioimmunotherapy. Two to three-day half-lives, intermediate-energy beta emissions, imageable photons, and suitable chemical characteristics make these radionuclides ideal for this application. Work on the production of high specific activity ⁶⁷Cu and ¹⁵³Sm, as well as the development of stable chelates for conjugating these radiometals to tumor-associated monoclonal antibodies is presented. Based on preliminary in vitro and in vivo studies (in nude mice xenografted with human colon carcinoma), both ⁶⁷Cu and ¹⁵³Sm appear very promising for tumor radioimmunotherapy and warrant continued investigation.