• Confirmed safety, pharmacokinetics, and dosimetry across cohorts
• No new safety signals, with hematologic events transient and manageable
• Tolerability profile supported by low-grade non-hematologic events and lesion dosimetry

The ProstACT Global Phase 3 study is evaluating TLX591-Tx, a novel radiopharmaceutical targeting prostate-specific membrane antigen (PSMA), in patients with metastatic castration-resistant prostate cancer (mCRPC) who have progressed on a first-line androgen receptor pathway inhibitor (ARPI) therapy. The Part 1 lead-in study enrolled 36 patients, each with one prior ARPI treatment, who received two doses of TLX591-Tx. The study demonstrated the feasibility of integrating TLX591-Tx with contemporary standards of care, meeting its primary and secondary endpoints of safety and dosimetry. No treatment-related deaths were observed, and 32 of the 36 patients remain alive, with 26 continuing on the study. The safety profile was acceptable, with most non-hematologic adverse events being low-grade and hematologic events being transient and manageable. The pharmacokinetic profile was predictable, with low inter-patient variability, and no evidence of drug-drug interactions. Lesion dosimetry confirmed the uptake of TLX591-Tx in tumors, with meaningful absorbed doses across lesion locations. These results support the continued development of TLX591-Tx in the Part 2 randomized expansion phase of the ProstACT Global study.

The ProstACT Global Phase 3 study is progressing, with Part 2 approved in select jurisdictions and enrolling patients. The Part 1 data has been completed, which is a prerequisite for progression to Part 2 in the U.S. The study is currently enrolling patients in Australia, New Zealand, and Canada following an independent data monitoring committee review, and regulatory approvals have been obtained to start the study in China, Singapore, South Korea, Japan, Türkiye, and the UK.