Posted: 17 March 2026
Telix Pharmaceuticals Limited has announced that Part 1 of the ProstACT Global Phase 3 clinical trial has achieved its primary objectives, with the company reporting an acceptable safety and tolerability profile for its investigational therapeutic candidate TLX591-Tx (lutetium-177 rosopatamab tetraxetan). No new safety concerns have been identified during the study.
Part 1 of the ProstACT Global trial has evaluated the safety, biodistribution and dosimetry of TLX591-Tx when administered in two doses, 14 days apart, in combination with standard-of-care therapies including abiraterone, enzalutamide or docetaxel. The study population has consisted of patients with prostate-specific membrane antigen (PSMA) positive metastatic castration-resistant prostate cancer (mCRPC) who had previously received treatment with one androgen receptor pathway inhibitor.
“These results reinforce the feasibility of integrating TLX591-Tx with current standard of care therapies for mCRPC, including ARPIs such as enzalutamide or abiraterone, or docetaxel,” said Neeraj Agarwal, MD, Professor of Medicine and Presidential Endowed Chair of Cancer Research at Huntsman Cancer Institute and ProstACT Global Principal Investigator. “Hematologic events align with those typically seen in this patient population and therapeutic class, and these cases resolved quickly.”
A total of 36 patients have been enrolled in Part 1 of the study across three cohorts: TLX591-Tx with enzalutamide (11 patients), TLX591-Tx with abiraterone (11 patients), and TLX591-Tx followed by docetaxel (14 patients). All participants received both planned doses of the therapy according to protocol.
Across the study cohorts, most treatment-emergent non-hematologic adverse events have been reported as Grade 1 or Grade 2, with fatigue, nausea and dry mouth among the most frequently observed. Hematologic events have been reported as transient and manageable, and radiation exposure to key organs has remained below established safety thresholds.
David N. Cade, MD, Group Chief Medical Officer at Telix, stated that the findings build on earlier clinical research evaluating the therapy. “Despite advances in clinical practice, men with advanced prostate cancer still need improved first and second line treatment options,” he said.
The ProstACT Global trial has already progressed to Part 2, a 2:1 randomised treatment expansion designed to compare PSMA-targeted lutetium-177 radio antibody-drug conjugate therapy administered with standard-of-care treatment versus standard-of-care therapy alone. Data from Part 1 will be presented to the United States Food and Drug Administration to support an amendment to the Investigational New Drug application and enable progression of the study in the United States.
