ProstACT Global Phase 3 Study (Part 1) Achieves Primary Objectives

• Webcast and conference call to be held today, Tuesday March 10 at 9:30 a.m. AEDT (Monday March 9 at 6:30 p.m. EDT). Investors can register at the following link: https://s1.c-conf.com/diamondpass/10053620-ju7y6t.html

MELBOURNE, Australia and INDIANAPOLIS, March 10, 2026 /PRNewswire/ -- Telix Pharmaceuticals Limited (ASX: TLX, NASDAQ: TLX, "Telix") today announces that Part 1 of the ProstACT Global Phase 3 study, the safety and dosimetry lead-in for its therapeutic candidate – TLX591-Tx (lutetium-177 (¹⁷⁷Lu) rosopatamab tetraxetan) – has achieved its primary objectives, demonstrating an acceptable safety and tolerability profile with no new safety signals observed.

Key findings include:

• Tolerability profile supported by dosimetry and low-grade non-hematologic events.
• Lesion dosimetry indicates no difference in absorbed dose profile across cohorts.
• No adverse drug-drug interactions observed in TLX591-Tx combinations.
• Hematologic events are in line with expectations and transient and manageable, with similar rates of recovery across all patient cohorts.
• The results from Part 1 are consistent with prior clinical studies of this first-in-class lutetium radio antibody-drug conjugate (rADC) therapy.

Part 1 of the study confirmed the safety profile, biodistribution and dosimetry of TLX591-Tx administered in two doses, 14 days apart, in combination with one of three standard of care (SOC) therapies: abiraterone, enzalutamide or docetaxel. The patient population comprised prostate-specific membrane antigen (PSMA) positive metastatic castration resistant prostate cancer (mCRPC) patients previously treated with one androgen receptor pathway inhibitor (ARPI).

ProstACT Global is a differentiated Phase 3 trial comparing PSMA-targeted ¹⁷⁷Lu-rADC therapy administered with SOC versus SOC alone, a trial design intended to reflect current global clinical practice^[1]. Telix has already advanced the study into Part 2 – a 2:1 randomized treatment expansion – in jurisdictions where the clinical trial has obtained approval from health authorities^[2]. Part 1 data will be presented to the United States (U.S.) Food and Drug Administration (FDA) to seek an Investigational New Drug (IND) amendment to progress Part 2 in the U.S.

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, "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. Hematologic events align with those typically seen in this patient population and therapeutic class, and these cases resolved quickly. The dosimetry profile, along with the low-grade nature of non-hematologic adverse events, further supports the tolerability profile of this investigational therapy."

David N. Cade, MD, Group Chief Medical Officer, Telix added, "Despite advances in clinical practice, men with advanced prostate cancer still need improved first and second line treatment options. These results build on prior findings and highlight the potential for TLX591-Tx in combination with contemporary standard of care, to become a new first-line option for patients facing this aggressive disease. We are encouraged by the data and look forward to engaging with the FDA at the earliest opportunity, while continuing to advance enrollment in Part 2 in regions where clinical trial initiation has already been approved."

Summary results

ProstACT Global Part 1 dosed 36 patients, allocated across 3 cohorts:

• Cohort 1 (11 patients): TLX591-Tx + enzalutamide.
• Cohort 2 (11 patients): TLX591-Tx + abiraterone.
• Cohort 3 (14 patients): TLX591-Tx followed by docetaxel.

Safety and tolerability

• An acceptable safety profile was observed across combination cohorts and tolerability of TLX591-Tx was consistent with prior studies.  
• All 36 patients received both doses of TLX591-Tx per protocol, no new safety signals were observed.
• Almost all treatment-emergent non-hematologic events were Grade 1 or Grade 2. The most prevalent were fatigue (53%), nausea (28%) and dry mouth (25%).
• Hematologic events were transient and manageable.
• Grade 3 thrombocytopenia (14%) and neutropenia (22%), and Grade 4 thrombocytopenia (31%) and neutropenia (25%) events were in line with the profile expected for this class of therapy and extent of disease.

Dosimetry and biodistribution

• Radiation exposure to key organs was well below established safety limits^[3].
• Limited dose to salivary glands and kidneys.
• Lesion dosimetry demonstrated uptake across tumor sites and across all cohorts.
• Pharmacokinetics demonstrated sustained activity at 15 days, corroborated by imaging which demonstrated prolonged tumor retention.
• No evidence of drug-drug interactions impacting TLX591-Tx targeting, distribution or clearance.

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 PET^[4] 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 approach demonstrates different targeting and pharmacology to that observed in other PSMA-targeted small molecule radioligand therapies (RLT). In contrast to these therapies^[5], collective long-term follow-up of patients administered with TLX591-Tx has not observed significant acute or delayed kidney toxicity, as the agent is primarily cleared through the liver, a comparatively radioresistant organ, instead of the kidneys^[6]. Due to its large molecular weight, TLX591-Tx also demonstrates minimal salivary and lacrimal gland uptake, reducing dry mouth and dry eyes, common adverse effects of existing PSMA-targeted RLTs^[7].

Additional information on the Phase 3 ProstACT Global study can be found at: https://telixpharma.com/prostact/

About Telix Pharmaceuticals Limited

Telix is a global biopharmaceutical company focused on the development and commercialization of therapeutic and diagnostic radiopharmaceuticals and associated medical technologies, with the goal to address significant unmet medical needs in oncology and rare diseases. With international operations in the United States, United Kingdom, Brazil, Canada, Europe (Belgium and Switzerland), and Japan, Telix is headquartered in Melbourne, Australia. Telix is listed on the Australian Securities Exchange (ASX: TLX) and the Nasdaq Global Select Market (NASDAQ: TLX).

Telix's Precision Medicine franchise includes llluccix®, approved in multiple markets globally, and Gozellix®, approved by the U.S. FDA^[8]. TLX591-Tx has not received a marketing authorization in any jurisdiction.

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.

This announcement has been authorized for release by the Telix Pharmaceuticals Limited Disclosure Committee on behalf of the Board. 

Legal Notices

Cautionary Statement Regarding Forward-Looking Statements. 

You should read this announcement together with our risk factors, as disclosed in our most recently filed reports with the Australian Securities Exchange (ASX), U.S. Securities and Exchange Commission (SEC), including our Annual Report on Form 20-F filed with the SEC, or on our website.

The information contained in this announcement is not intended to be an offer for subscription, invitation or recommendation with respect to securities of Telix Pharmaceuticals Limited (Telix) in any jurisdiction, including the United States. The information and opinions contained in this announcement are subject to change without notification.  To the maximum extent permitted by law, Telix disclaims any obligation or undertaking to update or revise any information or opinions contained in this announcement, including any forward-looking statements (as referred to below), whether as a result of new information, future developments, a change in expectations or assumptions, or otherwise. No representation or warranty, express or implied, is made in relation to the accuracy or completeness of the information contained or opinions expressed in the course of this announcement.

This announcement may contain forward-looking statements, including within the meaning of the U.S. Private Securities Litigation Reform Act of 1995, that relate to anticipated future events, financial performance, plans, strategies or business developments. Forward-looking statements can generally be identified by the use of words such as "may", "expect", "intend", "plan", "estimate", "anticipate", "believe", "outlook", "forecast" and "guidance", or the negative of these words or other similar terms or expressions. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to differ materially from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. Forward-looking statements are based on Telix's good-faith assumptions as to the financial, market, regulatory and other risks and considerations that exist and affect Telix's business and operations in the future and there can be no assurance that any of the assumptions will prove to be correct. In the context of Telix's business, forward-looking statements may include, but are not limited to, statements about: the initiation, timing, progress, completion and results of Telix's preclinical and clinical trials, and Telix's research and development programs; Telix's ability to advance product candidates into, enroll and successfully complete, clinical studies, including multi-national clinical trials; the timing or likelihood of regulatory filings and approvals for Telix's product candidates, including the planned NDA resubmission for TLX101-Px and the planned BLA resubmission for TLX250-Px, manufacturing activities and product marketing activities; Telix's sales, marketing and distribution and manufacturing capabilities and strategies; the commercialization of Telix's product candidates, if or when they have been approved; Telix's ability to obtain an adequate supply of raw materials at reasonable costs for its products and product candidates; estimates of Telix's expenses, future revenues and capital requirements; Telix's financial performance; developments relating to Telix's competitors and industry; the anticipated impact of U.S. and foreign tariffs and other macroeconomic conditions on Telix's business; and the pricing and reimbursement of Telix's product candidates, if and after they have been approved. Telix's actual results, performance or achievements may be materially different from those which may be expressed or implied by such statements, and the differences may be adverse. Accordingly, you should not place undue reliance on these forward-looking statements.

Trademarks and Trade Names. All trademarks and trade names referenced in this press release are the property of Telix Pharmaceuticals Limited (Telix) or, where applicable, the property of their respective owners. For convenience, trademarks and trade names may appear without the ® or ™ symbols. Such omissions are not intended to indicate any waiver of rights by Telix or the respective owners. Trademark registration status may vary from country to country. Telix does not intend the use or display of any third-party trademarks or trade names to imply any affiliation with, endorsement by, or sponsorship from those third parties.

©2026 Telix Pharmaceuticals Limited. All rights reserved.

^[1] National Comprehensive Cancer Network® Clinical Practice Guidelines in Oncology for Prostate Cancer V3.2026; Narayan et al. Clin Genitourin Cancer. 2024.
^[2] Part 2 is enrolling in Australia, New Zealand, and Canada, and has also received regulatory approval to commence in China, Singapore, South Korea, Türkiye, and the United Kingdom.
^[3] Wahl et al. J Nucl Med. 2021; Emami et al. Int J Radiat Oncol Biol Phys. 1991.
^[4] Positron emission tomography.
^[5] Tagawa et al. Curr Oncol Rep. 2021; Steinhelfer et al. J Nucl Med. 2024.
^[6] Tagawa et al. Cancer. 2019.
^[7] Pepin et al. Pract Radiat Oncol. 2025. 
^[8] Telix ASX disclosure March 21, 2025.

SOURCE Telix Pharmaceuticals Limited