The first part of the global ProstACT study has shown that the radiopharmaceutical TLX591-Tx (Lutetium-177 rosopatamab tetraxetan) is safe and tolerable when combined with standard therapies for advanced prostate cancer. The trial involved 36 patients with PSMA-positive metastatic castration-resistant prostate cancer who had already progressed on a first androgen receptor pathway inhibitor. Each patient received two doses of TLX591-Tx along with enzalutamide, abiraterone, or docetaxel.
The treatment was generally well tolerated, with mostly low-grade side effects such as fatigue, nausea, and dry mouth. Expected blood-related side effects, including thrombocytopenia and neutropenia, occurred but resolved quickly. All patients were able to complete the full dosing protocol, and no new safety concerns or drug interactions were observed.
These results suggest TLX591-Tx could be used earlier in prostate cancer treatment rather than only in late stages. The study is moving into its second phase, which will enroll about 490 patients to compare these combinations against standard therapy alone, focusing on radiographic progression-free survival. The data will be submitted to the FDA to support this next step.