terbium-161 SibuDAB

Terbium-161 SibuDAB is a novel radioligand designed for targeted radionuclide therapy (RLT) in metastatic castration-resistant prostate cancer (mCRPC). It combines the radionuclide terbium-161 with SibuDAB, a prostate-specific membrane antigen (PSMA) targeting ligand that features albumin-binding properties. These albumin-binding properties provide prolonged circulation time, enhancing tumor accumulation and radiation delivery, particularly to micrometastases. Terbium-161 offers potential advantages over the commonly used lutetium-177 in RLT. While both radionuclides have similar half-lives, terbium-161 emits not only β-particles and γ-rays but also conversion and Auger electrons, which may be particularly effective at eliminating micrometastases and single cancer cells. In preclinical studies, [161Tb]Tb-SibuDAB demonstrated enhanced blood residence time and higher tumor uptake (62-69% injected activity per gram at 24h) compared to conventional PSMA ligands like PSMA-I&T (30-35% injected activity per gram at 24h). This resulted in a 4-fold increased absorbed tumor dose and more effective tumor growth inhibition.