Melbourne, Australia & Indianapolis, Indiana, USA | July 22, 2026
Telix Pharmaceuticals announced the peer-reviewed publication of results from its Phase 1 ProstACT SELECT study in the journal Cancers, providing additional scientific validation for its investigational PSMA-targeting radio antibody-drug conjugate (rADC) TLX591-Tx (lutetium-177 rosopatamab tetraxetan). The publication confirms that 68Ga-PSMA-PET imaging can effectively identify patients most likely to benefit from TLX591-Tx therapy using a theranostic approach, where diagnostic imaging guides targeted radiopharmaceutical treatment. The findings also reinforce the therapy’s differentiated clinical profile, including prolonged tumor retention, an intensified dosing schedule, and low radiation exposure to salivary glands, while supporting the ongoing global Phase 3 ProstACT trial in patients with metastatic castration-resistant prostate cancer (mCRPC). The publication represents an important milestone in strengthening the scientific foundation for Telix’s lead therapeutic program targeting advanced prostate cancer.
Study Demonstrates Effective PSMA-PET Patient Selection for Targeted Therapy
The ProstACT SELECT Phase 1 study was designed to evaluate whether 68Ga-PSMA-PET imaging, marketed as Illuccix, could accurately identify patients suitable for treatment with TLX591-Tx by comparing PET imaging findings with multi-time-point SPECT imaging. Investigators demonstrated strong lesion concordance between the two imaging approaches, confirming that both technologies consistently targeted the same prostate cancer lesions. This validation supports the use of PSMA-PET imaging as an effective patient-selection tool within a theranostic treatment strategy, helping clinicians identify individuals who are most likely to respond to targeted radiopharmaceutical therapy. The results provide important evidence supporting Telix’s imaging-guided precision medicine approach as development progresses into late-stage clinical evaluation.
Published Data Highlight Safety Profile and Clinical Differentiation
The peer-reviewed publication also reported encouraging clinical outcomes for TLX591-Tx when administered alongside standard-of-care therapy in patients with advanced metastatic castration-resistant prostate cancer. The investigational therapy demonstrated a manageable and predictable safety profile, while achieving prolonged tumor retention and reduced irradiation of exocrine tissues, particularly the salivary glands, an important consideration for radiopharmaceutical therapies. Among evaluable patients, investigators reported a median radiographic progression-free survival (rPFS) of 8.8 months, indicating promising anti-tumor activity in a heterogeneous patient population representative of real-world clinical practice. According to study investigators, these findings further differentiate TLX591-Tx from existing therapeutic approaches while supporting continued clinical development.
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Phase 3 ProstACT Global Trial Continues in Advanced Prostate Cancer
According to Dr. Nat Lenzo, Principal Investigator of the ProstACT SELECT study, the published findings demonstrate that PSMA-PET imaging can reliably identify appropriate candidates for TLX591-Tx therapy, providing strong support for the patient-selection strategy being used in the ongoing international Phase 3 ProstACT Global trial. Dr. David N. Cade, Group Chief Medical Officer at Telix, noted that the publication strengthens confidence in the therapy’s durable tumor targeting, hepatobiliary clearance profile, and manageable safety characteristics, all of which are important differentiators for targeted radiopharmaceutical therapies. TLX591-Tx remains Telix’s lead PSMA-targeting therapeutic candidate and is currently being evaluated in the multicenter Phase 3 ProstACT Global study, where the company aims to improve treatment outcomes for patients with advanced metastatic castration-resistant prostate cancer, an area that continues to face significant unmet medical need despite recent therapeutic advances.
Source: Telix press release
