In the current project, we want to assess the safety and tolerability the novel PSMA radioligand 161Tb-SibuDAB. Terbium-161 (161Tb) emits β-minus particles and, in addition, a substantial amount of conversion and Auger electrons. These electrons have a tissue range of a few nanometers, resulting in a 2-4-fold higher radiation dose to CTC and tumor cell clusters. Furthermore, we want to assess a potential correlation between CTC/clusters and response to standard RLT. The team at PSI is responsible for the production of 161Tb-SibuDAB (including the radionuclide), the team at the ETH Zurich is analyzing the blood samples of patients for the presence of CTC and tumor cell clusters with its technique and the team at USB will conduct the clinical study.
RLT emerged as an effective means for the treatment of patients with prostate-specific membrane antigen (PSMA)-positive mCRPC. Despite the success of this therapy, 1/3 of the patients do not or only temporarily respond to treatment with β-minus particle emitting radionuclide only such as Lutetium-177. It is hypothesized that the insufficient radiation dose delivery to macroscopic tumors and to microscopic metastases with currently used 177Lu-based PSMA radioligands is the reason for the treatment failure in these patients.
