Radioactive antibodies are used as imaging agents for positron emission tomography (PET) – an imaging technique that improves cancer diagnosis and monitoring of chemotherapy. Radioactive antibodies are also used for radioimmunotherapy. They identify cancer cells in the body and deliver a radioactive payload directly to the cancer cells. This ensures that the surrounding, healthy tissue does not suffer any damage. However, radiolabeling proteins is time-consuming and difficult to automate, according to the University of Zurich (UZH). Researchers at UZH have now changed this.
In conventional methods, the protein is purified, coupled to a metal-binding chemical substance, isolated, stored, and then radiolabeled. The new, innovative method developed by researchers at UZH uses UV light to synthesize radioactive drugs and diagnostic agents. Professor Jason P. Holland comments: “By combining photochemistry with radiochemistry, we are now able to make radiolabeled proteins much more quickly and easily – literally in a flash of light”. According to the information provided, under the new method, radiolabeled antibodies are ready-for-use in just 15 minutes.
Using the new method, researchers were able to label trastuzumab, an antibody used to treat breast cancer patients, with radioactive gallium in less than 20 minutes. Moreover, researchers have managed to further develop their method in such a way that the radiolabeling decays much less rapidly, which is of huge importance particularly in terms of PET imaging.
“Automated photoradiochemical synthesis has the potential to revolutionize the way in which radiolabeled antibodies and other proteins are used in science and medicine”, Holland says. He has therefore submitted a patent application for the new procedure and aims to develop the technology commercially. A further target is also to further develop the method so that it can be used to treat other cancer indications.