The New Wave in Cancer Treatment: Customized Nuclear Medicine

Targeted radiation may also be useful in treating other diseases.

Customized nuclear medicine may offer a more effective method to treat cancer and other diseases, the results of a new study found.

Published in the December 2014 issue of The Journal of Nuclear Medicine, researchers evaluated targeted therapy with radiopharmaceuticals, which are radioactive compounds used in nuclear medicine for diagnosis or treatment. This approach provides a possible glimpse into the future of cancer care, specifically in treating cancer cells the moved from primary tumors to lymph nodes and secondary organs such as bone marrow, the researchers wrote.

Due to significant differences in the amount of targetable receptors on each cell, these tumors are a challenge for single targeting agents.

Radiopharmaceuticals have a variety of uses in both imaging and as active therapeutic treatments across a wide range of medical conditions including cancers, thyroid conditions, and polycythemia vera.

As part of the study, the researchers treated breast cancer cells with different concentrations of a mix of 4 fluorochrome-conjugated monoclonal antibodies, determining the amount of each antibody tied to each cell using flow cytometry. The antibodies were armed with formulas that were developed with the desired radionuclide and activity.

The researchers calculated the absorbed dose to each cell and conducted a simulation of the surviving fraction of cells after they were subjected to cocktails with different combinations of antibodies.

"Our approach moves radiation treatment planning for cancer therapy from the tumor level to the molecular and cellular level, with nuclear medicine serving as the treatment engine," lead researcher Roger Howell, PhD, said in a press release. "The concepts are not restricted to cancer therapy but can be applied more widely to other diseases that may benefit from a targeted approach with cocktails of radiopharmaceuticals. The approach can also be extended to cocktails consisting of radiopharmaceuticals and non-radioactive agents."

In a comparison of the effect of radiopharmaceutical cocktails versus single antibodies, the cocktails outperformed single antibodies by a factor of up to 244 in certain activities, which suggests targeted alpha therapy can be enhanced with customized radiolabeled antibody cocktails, the study noted. The cocktails can offer a significant advantage in eliminating tumor cells, dependent on the antibody combination and specific activity of the radiolabeled antibodies, the study found.

The study may also provide a foundation for prediction of tumor cell survival prior to treatment within personalized cancer therapy, the researchers noted.

"This method is preferable, as it accounts for behavior of the drugs in the patient's body," Dr. Howell noted. "The beauty of either approach for planning a treatment is that the patient is not subjected to any radiopharmaceutical injections during the planning phase, which uses only fluorescent-labeled drugs. The patient is not injected with radiopharmaceuticals until the treatment phase, whereupon only a cocktail specifically optimized for that individual is administered. This spares the patient from receiving ineffective cocktails that may damage normal tissues and prevent further treatment."