ProstACT Phase 3 Trial Completes Part 1 Enrolment, Expands Across Seven Countries

ProstACT Phase 3 Trial Progresses to Next Stage

Telix Pharmaceuticals has provided a detailed update on the status of its ProstACT Global Phase 3 clinical trial, investigating TLX591, a novel prostate cancer therapy candidate targeting metastatic castration resistant prostate cancer (mCRPC). The company confirmed that patient enrolment for Part 1, which focused on safety and dosimetry, has been completed in line with the study protocol.

This initial phase involved three cohorts, including patients receiving docetaxel, and was designed to assess the safety profile of TLX591 when combined with standard of care treatments such as abiraterone, enzalutamide, or docetaxel. The Independent Data Monitoring Committee (IDMC) has reviewed the data and recommended advancing to Part 2, indicating no unexpected safety concerns.

Global Expansion and Regulatory Milestones

Following the positive safety review, Telix has commenced Part 2 of the ProstACT trial, which involves a randomized treatment expansion with a target enrolment of approximately 490 patients globally. The trial is now open for enrolment in Australia, New Zealand, and Canada, with regulatory approvals also secured in China, Singapore, Türkiye, the United Kingdom, South Korea, and Japan. Notably, the Japanese Pharmaceuticals and Medical Devices Agency approved a Japan-specific Part 1 cohort prior to Part 2 initiation.

Telix is preparing to submit a clinical trial application to the European Medicines Agency (EMA) to facilitate expansion into European Union sites, further broadening the trial’s international footprint.

Distinctive Therapeutic Profile of TLX591

TLX591 distinguishes itself from other PSMA-targeted radioligand therapies by its antibody-based mechanism, which results in different pharmacology and targeting. Importantly, long-term follow-up has not revealed significant kidney toxicity, a common concern with small peptide radioligand therapies, as TLX591 is cleared through the liver. Additionally, the therapy shows limited uptake in salivary and lacrimal glands, potentially reducing side effects such as dry mouth and dry eyes.

Preliminary data from Part 1 will be submitted to the U.S. Food and Drug Administration (FDA) to determine eligibility for U.S. patient participation in Part 2. These results will be publicly disclosed at the time of data readout and FDA engagement, marking a critical milestone for the therapy’s development.

Looking Ahead

As Telix advances ProstACT Global into its next phase, the company is positioning TLX591 as a promising addition to the prostate cancer treatment landscape. The ongoing trial’s outcomes will be closely watched by investors and clinicians alike, given the potential to address significant unmet needs in metastatic castration resistant prostate cancer.