FDA Alignment to Advance ProstACT Global Phase 3 Trial

Melbourne (Australia) and Indianapolis, IN (United States) | July 2, 2026

  • FDA and Telix align on advancement into Part 2 of the ProstACT Global Phase 3 study in the United States.
  • FDA agrees with the clinical protocol and proposed statistical framework across three standard-of-care combination cohorts.
  • Part 2 (randomized cohort) continues to recruit in jurisdictions where the study has regulatory approval.

Telix today announced the successful outcome of a Type B meeting with the United States (U.S.) Food and Drug Administration (FDA) to review the Part 1 safety and dosimetry data and Part 2 protocol design of the ProstACT Global Phase 3 trial of its therapeutic candidate TLX591-Tx (lutetium-177 (177Lu) rosopatamab tetraxetan) in metastatic castration resistant prostate cancer.

The FDA has confirmed that the safety data from Part 1 of the study is sufficient to enable progression of Part 2 of ProstACT Global into the U.S. in which TLX591-Tx is administered in two doses, 14 days apart, in combination with one of three randomized standard of care (SOC) therapies: abiraterone, enzalutamide or docetaxel. The FDA and Telix also achieved alignment on the Part 2 clinical trial protocol, statistical analysis plan, and ongoing safety monitoring plan. The result is a consistent framework for study execution as enrollment continues internationally and expands into the U.S.

David N. Cade, MD, Group Chief Medical Officer, Telix, said, “This is an excellent outcome that   enables submission of our IND amendment for initiation of Part 2 of ProstACT Global in the U.S. Part 2 continues to enroll strongly in regions where recruitment is open.”

Neeraj Agarwal, MD, Professor of Medicine and Presidential Endowed Chair of Cancer Research at Huntsman Cancer Institute, Salt Lake City, and ProstACT Global Principal Investigator and Steering Committee member, commented, “TLX591-Tx has the potential to redefine how radiopharmaceutical therapy is integrated into clinical practice. Because the complete treatment course is delivered over approximately two weeks, physicians can layer it into an existing regimen with minimal interruption, providing greater flexibility to sequence therapies while preserving future treatment options in patients with metastatic prostate cancer.”

Initiation of Part 2 in the U.S. remains subject to the FDA’s review of an Investigational New Drug (IND) amendment. The IND amendment will also be aligned with a pending regulatory submission to initiate the ProstACT Global study in Europe. The trial continues to enroll patients in regions where Part 2 is approved[1].


About ProstACT Global

ProstACT Global (ClinicalTrials.gov ID: NCT06520345) is an international, multicenter trial in two parts: Part 1, safety and dosimetry lead-in with 36 patients (complete); and Part 2, 2:1 randomized global expansion with an overall target enrollment of approximately 490 patients. Eligible patients must have confirmed progressive mCRPC assessed with a 68Ga-PSMA-11 PET4 imaging agent (such as Illuccix®, kit for the preparation of gallium-68 (68Ga) gozetotide injection, or Gozellix®, kit for the preparation of gallium-68 (68Ga) gozetotide injection) following prior treatment with one ARPI.

The antibody-based approach demonstrates differentiated targeting and pharmacology to other PSMA-targeted small molecule radioligand therapies (RLT). In contrast to these therapies5, collective long-term follow-up of patients administered with TLX591-Tx has not observed significant acute or delayed kidney toxicity, as the agent is hepatically (liver) excreted, a comparatively radioresistant organ6. TLX591-Tx also demonstrates minimal salivary and lacrimal gland uptake, reducing the prevalence of xerostomia (dry mouth) and dry eye, which are typical adverse effects of existing PSMA-targeted RLTs7. Additional information on the Phase 3 ProstACT Global study can be found at: https://telixpharma.com/prostact/

[1] Part 2 is enrolling in Australia, New Zealand, Canada, Türkiye, and the United Kingdom, and has also received regulatory approval to commence in China, Singapore and South Korea.

TLX591-Tx has not received a a marketing authorization in any jurisdiction.