Melbourne, Australia, and Indianapolis, Indiana, United States, July 2, 2026
Telix announced a significant regulatory milestone after a successful Type B meeting with the U.S. Food and Drug Administration (FDA) regarding its ProstACT Global Phase 3 clinical trial evaluating TLX591-Tx (lutetium-177 rosopatamab tetraxetan) for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Following a comprehensive review of Part 1 safety and dosimetry data, the FDA confirmed that the available clinical evidence is sufficient to support advancement into Part 2 of the Phase 3 study in the United States. The agency also agreed with the proposed clinical protocol, statistical analysis framework, and ongoing safety monitoring strategy, providing Telix with a clear regulatory pathway as it prepares to submit an Investigational New Drug (IND) amendment. This important FDA alignment strengthens the company’s efforts to expand patient enrollment globally while accelerating development of one of its lead radiopharmaceutical oncology programs.
Randomized Phase 3 Trial Expands Across Multiple Standard-of-Care Therapies
The Part 2 ProstACT Global Phase 3 study is designed as a randomized trial evaluating TLX591-Tx administered in two treatment doses delivered 14 days apart alongside one of three established standard-of-care (SOC) therapies: abiraterone, enzalutamide, or docetaxel. By incorporating these commonly used treatment regimens, the study aims to determine whether the targeted radiopharmaceutical can improve clinical outcomes while integrating seamlessly into current prostate cancer treatment strategies. Telix confirmed that patient recruitment continues across international regions where regulatory approvals have already been obtained, while preparations are underway for expansion into the United States pending FDA review of the IND amendment. The company also noted that the submission will align with an ongoing regulatory application seeking authorization to initiate the ProstACT study across Europe, supporting a coordinated global development strategy.
TLX591-Tx Designed to Enhance Flexibility in Prostate Cancer Treatment
According to Telix and the study investigators, TLX591-Tx has the potential to reshape the treatment landscape for patients with advanced prostate cancer by offering a highly targeted radiopharmaceutical therapy that can be delivered over approximately two weeks. This condensed treatment schedule may allow physicians to incorporate the therapy into existing treatment plans with minimal disruption while preserving future therapeutic options. Investigators believe this flexible approach could help optimize treatment sequencing in patients with metastatic castration-resistant prostate cancer, a disease where long-term management often requires multiple lines of therapy. The therapy utilizes lutetium-177, a therapeutic radioisotope designed to selectively deliver radiation to prostate cancer cells expressing prostate-specific membrane antigen (PSMA), potentially maximizing tumor control while limiting exposure to healthy tissues.
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Regulatory Progress Strengthens Telix’s Oncology Development Pipeline
The successful FDA meeting represents another important milestone in Telix’s radiopharmaceutical development strategy, reinforcing regulatory confidence in the ProstACT clinical program and supporting continued advancement toward potential commercialization. Company leadership stated that FDA agreement on the study protocol, statistical design, and safety monitoring creates a consistent framework for global execution while reducing regulatory uncertainty during late-stage development. As enrollment continues internationally and U.S. participation moves closer following IND review, Telix remains focused on generating robust Phase 3 evidence that could establish TLX591-Tx as a new treatment option for patients with metastatic castration-resistant prostate cancer. The coordinated regulatory approach across the United States and Europe also reflects the company’s commitment to accelerating global access to innovative targeted radiopharmaceutical therapies, an area experiencing rapid growth within precision oncology.
Source: Telix press release
