OPTIMAL-PSMA Trial of TLX597-Tx Next Generation RLT Presented at IPCS 2026 Highlighting Therapeutic Potential in Prostate Cancer
Rhea-AI Summary
Telix (ASX: TLX, NASDAQ: TLX) presented Phase 2 OPTIMAL-PSMA dosimetry data for TLX597-Tx at IPCS 2026 showing low salivary gland and kidney uptake and comparatively higher tumor uptake. Findings support dose intensification, potential improved tolerability, and initiation of a Phase 2 OPTIMAL-E study in earlier-stage mHSPC.
The randomized 120-patient OPTIMAL-PSMA trial used an intensified 8.5 GBq per-cycle regimen and compared safety, dosimetry and efficacy versus a standard schedule; TLX597-Tx and TLX591-Tx remain unapproved.
Positive
- Low salivary gland and kidney uptake observed in OPTIMAL-PSMA dosimetry
- Higher tumor uptake versus existing PSMA RLTs, supporting a wider therapeutic window
- OPTIMAL-PSMA used an intensified 8.5 GBq per-cycle regimen (day 1, 3, 15) enabling dose intensification
- Telix initiating OPTIMAL-E Phase 2 in mHSPC to study TLX597-Tx in earlier-stage disease
Negative
- No marketing authorization for TLX597-Tx or TLX591-Tx in any jurisdiction
- OPTIMAL-PSMA results are dosimetry-focused; efficacy and long-term safety outcomes not yet reported
- Data come from a Phase 2 investigator-initiated trial (IIT), not a completed pivotal study
News Market Reaction – TLX
In the Apr 30 session, TLX gained 5.47%, reflecting a notable positive market reaction.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Apr 21 | Clinical data update | Positive | +1.2% | ASCO 2026 late-breaking safety and tolerability data for ProstACT Global Part 1. |
| Apr 14 | Clinical trial start | Positive | -0.4% | First patient dosed in Phase 3 IPAX-BrIGHT trial for recurrent glioblastoma. |
| Apr 13 | Strategic partnership | Positive | +6.6% | 50/50 co-development and co-commercialization radiopharma deal with Regeneron. |
| Apr 09 | Regulatory milestone | Positive | +7.5% | FDA acceptance of resubmitted NDA for TLX101-Px with set PDUFA goal date. |
| Apr 08 | Board changes | Positive | +0.2% | Appointment of two new Non-Executive Directors to strengthen governance and expertise. |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
Recent Telix news has mostly led to positive price reactions, especially for major partnerships and regulatory milestones, with one divergence on a clinical trial start.
Over recent months Telix has reported several significant developments, including a strategic collaboration with Regeneron, an FDA NDA acceptance for TLX101-Px with a September 11, 2026 PDUFA goal date, and board expansion effective May 11, 2026. Clinical momentum includes selection of ProstACT Global Phase 3 Part 1 as a late-breaking abstract at ASCO 2026 and first dosing in the Phase 3 IPAX-BrIGHT glioblastoma trial. The new OPTIMAL-PSMA Phase 2 dosimetry data fits this pattern of advancing a diversified radiopharma pipeline across multiple indications.
Key Terms
radioligand therapy medical
psma medical
dosimetry medical
xerostomia medical
renal toxicity medical
mcrpc medical
antibody-drug conjugate medical
AI-generated analysis. How Rhea-AI works. Not financial advice.
- TLX597-Tx is a PSMA1-targeting small molecule radioligand therapy (RLT) candidate, designed to improve quality-of-life and efficacy in earlier-stage prostate cancer.
- OPTIMAL-PSMA2 initial dosimetry data demonstrate low salivary gland and kidney uptake, supporting dose intensification.
- Telix is developing two distinct prostate therapeutic programs, tailored to disease stage and patient condition: TLX591-Tx radio antibody-drug conjugate (rADC) in combinations with standard of care (Phase 3 in mCRPC3) and TLX597-Tx intended for earlier-stage mHSPC4.
- Webcast today: Thursday, April 30, at 9:30 a.m. AEST (Wednesday, April 29, at 7:30 p.m. EDT). Register here: https://s1.c-conf.com/diamondpass/10053985-675tre.html
MELBOURNE, Australia and INDIANAPOLIS, April 30, 2026 (GLOBE NEWSWIRE) -- Telix Pharmaceuticals Limited (ASX: TLX, NASDAQ: TLX, “Telix”) today announces dosimetry results from the randomized Phase 2 OPTIMAL-PSMA trial of TLX597-Tx in metastatic castration-resistant prostate cancer (mCRPC), presented at the 2026 International Prostate Cancer Symposium (IPCS 2026) held in Lugano, Switzerland. These findings support TLX597-Tx’s potential to deliver a treatment that overcomes quality-of-life challenges that currently limit the clinical utility of existing RLTs in earlier-stage metastatic prostate cancer.
TLX597-Tx (177Lu-DOTA-HYNIC-panPSMA) is a novel PSMA-targeting small molecule RLT candidate with a highly favorable dosimetry profile. Significantly reduced radiation exposure to healthy organs, including the salivary glands and kidneys5, may lower the incidence of xerostomia (dry mouth) and renal toxicity and support better tolerability for patients. This dosimetry profile combined with higher tumor uptake compared to existing PSMA RLTs may deliver a wider therapeutic window and enable dose intensification to maximize tumor control while preserving patient quality-of-life.
OPTIMAL-PSMA is an open-label, multi-center, randomized, Phase 2 investigator-initiated trial (IIT) led by Professor Louise Emmett at St Vincent’s Hospital in Sydney, Australia. The study is evaluating the safety, dosimetry, and efficacy of an intensified dosing regimen of TLX597-Tx compared with a standard dose schedule in 120 men with advanced mCRPC, randomized on a 2:1 basis. The novel dose-intensification regimen delivers higher activity per cycle (8.5 GBq), delivered on day 1, day 3 and day 15, followed by 10-weekly dosing for three further cycles. The study aims to confirm that a dose intensified TLX597-Tx regimen will maximize the radiation dose to cancerous lesions when they are most vulnerable to damage and therefore improve overall response to treatment.
Telix believes these dosimetry data support further evaluation of TLX597-Tx in earlier-stage disease and is initiating OPTIMAL-E, a Phase 2 study in androgen pathway-sensitive prostate cancer (mHSPC).
Principal Investigator for OPTIMAL-PSMA, Professor Louise Emmett, commented, “The goal of OPTIMAL-PSMA is to identify a dose regimen for TLX597-Tx that leads to deeper and longer responses without increasing toxicity for men with metastatic prostate cancer. We look forward to starting the Phase 2 OPTIMAL-E trial soon.”
Dr. David N. Cade, Group Chief Medical Officer at Telix, added, “These encouraging dosimetry results from OPTIMAL-PSMA, combined with earlier exploratory work6, are very promising and highlight TLX597-Tx’s potential to substantially increase the tumor dose while minimizing radiation to sensitive organs. For people living with earlier-stage metastatic disease, preserving quality-of-life alongside effective cancer control is mandatory. These findings support further study in mHSPC and reinforce Telix’s strategy to develop differentiated PSMA-targeting therapies, so clinicians may be able to tailor treatment choice to the patient’s disease stage and individual condition.”
TLX597-Tx is being developed alongside TLX591-Tx (lutetium-177 (177Lu) rosopatamab tetraxetan), Telix’s lead antibody-based prostate cancer therapy candidate, currently the subject of the Phase 3 ProstACT Global7 trial in mCRPC, which is actively dosing patients in jurisdictions with regulatory approval and recently reported data from a safety and dosimetry lead-in8. TLX591-Tx and TLX597-Tx exhibit complementary modes-of-action, suggesting the potential for distinct applications in mCRPC and mHSPC settings as part of Telix’s portfolio approach to treating prostate cancer. TLX591-Tx and TLX597-Tx have not received marketing authorization in any jurisdiction.
To view the webcast slides, click here.
About Telix Pharmaceuticals Limited
Telix is a global biopharmaceutical company focused on the development and commercialization of radiopharmaceuticals with the goal of addressing significant unmet medical need in oncology and rare diseases. Telix is headquartered in Melbourne (Australia) with international operations in the United States, United Kingdom, Brazil, Canada, Europe (Belgium and Switzerland) and Japan. Telix is listed on the Australian Securities Exchange (ASX: TLX) and the Nasdaq Global Select Market (NASDAQ: TLX).
Visit www.telixpharma.com for further information about Telix, including details of the latest share price, ASX and U.S. Securities and Exchange Commission (SEC) filings, investor and analyst presentations, news releases, event details and other publications that may be of interest. You can also follow Telix on LinkedIn, X and Facebook.
| Telix Investor Relations (Global) Ms. Kyahn Williamson SVP Investor Relations and Corporate Communications kyahn.williamson@telixpharma.com | Telix Investor Relations (Australia) Ms. Charlene Jaw Associate Director Investor Relations charlene.jaw@telixpharma.com | Telix Investor Relations (U.S.) Ms. Annie Kasparian Director Investor Relations and Corporate Communications annie.kasparian@telixpharma.com |
| Media Contact Eliza Schleifstein 917.763.8106 (Mobile) Eliza@schleifsteinpr.com | ||
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1 Prostate-specific membrane antigen.
2 Australian New Zealand Clinical Trials Registry ID: ACTRN12625000971437.
3 Metastatic castration-resistant prostate cancer.
4 Metastatic hormone-sensitive prostate cancer.
5 Steinhelfer et al. J Nucl Med. 2024.
6 Omar et al., presented at the European Association of Nuclear Medicine 2025 Annual Congress.
7 ClinicalTrials.gov ID: NCT06520345.
8 Telix ASX disclosure March 10, 2026.
