Terbium labeling of anti-CEA nanobodies for in vivo imaging and therapy of colorectal cancer

In Belgium, colorectal cancer is the third most diagnosed cancer in men and second most diagnosed cancer in women. Nuclear medicine plays an important role in the diagnosis, follow-up and treatment of cancer. Ideally, the diagnostic radiopharmaceutical has an identical chemical structure than the therapeutic radiopharmaceutical, so that the pharmacokinetic properties of both compounds are equal, and that accurate dosimetry is possible. This can only be achieved if radionuclides for both diagnostic and therapeutic use of the same element are available. This is the case for the radiometal Terbium which has four medically interesting isotopes both for diagnostic and therapeutic use. The aim of this project is to develop and evaluate new terbium-based radiopharmaceuticals for diagnosis and therapy of colorectal cancer. For this purpose, nanobodies (Nbs) that specifically target colorectal cancer cells (anti-CEA Nb) will be used as vector molecule and radiolabeled with diagnostic and therapeutic terbium isotopes. The labeled Nbs will be fully evaluated and ready for clinical translation by the end of this project. In conclusion, these innovative terbium-based radiopharmaceuticals will allow a more accurate diagnosis, treatment and follow-up of colorectal tumor patients, which is highly needed.