Radiopharm Theranostics Ltd (ASX:RAD) has signed an expanded agreement with radionuclide production company TerThera to supply the company with Terbium-161 (Tb-161) ahead of a Phase 1 dosing trial on patients with advanced prostate cancer next year.
The Tb-161 isotope will be linked to a proprietary monoclonal antibody (mAb) to form RAD 402, a radiotherapeutic that is being developed by Radiopharm to target KLK3 expression. KLK3 is highly expressed in prostate cancer cells but has limited expression in healthy tissue.
Radiopharm has plans to initiate a Phase I dose-escalating trial during the second half of 2024, to evaluate the safety and efficacy of RAD 402 in patients with advanced prostate cancer.
Superior preclinical results
Radiopharm CEO and managing director Riccardo Canevari said: “We are excited about bringing this highly differentiated technology (Tb161-RAD402) to patients with advanced prostate cancer.
“Until now, Prostate-Specific Membrane Antigen (PSMA) targeting agents represent the only theranostic option in the market or in development. RAD has decided to leverage a different mechanism of action by targeting KLK3, and the combination with Tb-161 is unique and highly promising.
“Tb-161 has shown superior preclinical results in comparison with Lu-177, which may translate into higher absorbed doses in micrometastatic disease, with less kidney toxicity. This novel radiopharmaceutical has the potential to become the first KLK-based theranostic option for individuals with advanced prostate cancer.
“We signed a first agreement with TerThera in April 2023 for RAD 602 in brain cancer and now we have decided to amplify, developing a second molecule linked with Terbium-161. We are the first company that has access to Terbium-161 for the clinical development of two different molecules. This is a really exciting innovation!”
Terbium-161 is a highly promising isotope for targeted cancer treatment due to its unique characteristics of radiation emitted, which includes both Auger electrons and short-range beta particles.
Tb‑161 compares well to currently used radiolanthanides and is “potentially superior” to Lutetium-177 (Lu-177) as its Auger effect increases potency and efficacy in selectively destroying tumour cells while leaving surrounding healthy tissue largely unaffected.