The idea of using radiation therapy as cancer treatment is more than one hundred years old. In 1895, Wilhelm Conrad Röntgen discovered x-rays as a new form of “radiation”, later leading to the development of diagnostic imaging-techniques. In 1896, with Henri Becquerel discovering the radiation of natural agents and chemicals and Marie Curie’s fundamental work on radioactivity, the path for the use of radioactive agents as medical treatment options was carved. Soon after, various radiotherapy approaches for a wide range of diseases, often including cancer, were investigated and developed.
In contrast to radiotherapy, where radiation is applied from outside the body, Targeted Radionuclide Therapy is defined by the injection of a radiopharmaceutical into the body which precisely recognizes tumor cells. Over the past decades, biomedical investigations on various tumor characteristics and tumor-binding molecules have contributed to the evolution of radiation therapy towards Precision Oncology and the development of Targeted Radionuclide Therapy.
Targeted Radionuclide Therapy uses radiopharmaceuticals consisting of a medical radioisotope and a tumor-specific targeting molecule that binds precisely to the tumor-specific receptor on the tumor cell surface according to the lock and key principle. A very small amount of medical radiation is sufficient for this therapeutic approach. In many cases, the targeting molecule can be used for both diagnosis and therapy, only the radioisotope has to be changed from a diagnostic to a therapeutic one. Radioisotopes with shorter half-lives are used for diagnosis and radioisotopes with slightly longer half-lives for therapy.
The radiopharmaceutical being investigated in the phase III clinical trial COMPETE is n.c.a. Lutetium-177-Edotreotide. It consists of two components: the therapeutic radioisotope no-carrier-added Lutetium-177 (n.c.a. 177Lu) and the biomolecule Edotreotide targeting neuroendocrine tumor specific receptors.
The therapeutic radioisotope n.c.a. 177Lu emits medical radioactivity (ionizing β-radiation) which is used to destroy the tumor. The tumor-specific targeting molecule Edotreotide is a synthetic biomolecule which acts like Somatostatin, a human hormone released by the pancreas during the digestive process. Just like the physiological hormone Somatostatin, Edotreotide binds to the somatostatin receptors which are overexpressed on the neuroendocrine tumor cell surface according to the lock and key principle. As a result, the therapeutic radioisotope accumulates at the tumor site. After binding to the tumor cell surface, the radioisotope decays, releasing medical radiation with a maximum radius of 1.7 mm and destroying the tumor. The highly precise localization ensures that healthy tissue surrounding the targeted tumor is minimally affected. The radiopharmaceutical is produced in a laboratory under Good Manufacturing Practice (GMP), underlying strict certified international guidelines.
Please note: n.c.a. 177Lu-Edotreotide is not authorized for marketing in any country at this time.
Please also see study information on www.clinicaltrials.gov