Telix Completes Proof-of-Concept Study of TLX592 Targeted Alpha Therapy in Prostate Cancer

• CUPID is a Phase I safety and dosimetry study of TLX592, Telix’s investigational antibody-based targeted alpha therapy for prostate cancer.
• Establishes proof-of-concept for Telix’s proprietary RADmAb® engineered antibody platform, currently under pre-clinical evaluation for multiple cancer targets.
• Initial results demonstrate rapid elimination from blood circulation compared to standard antibodies and hepatic (liver) clearance – both highly desirable characteristics for use with alpha emitting agents.
• Successful completion of mass dose escalation study establishes a baseline dosing schedule for future studies of TLX592 using actinium-225.
• Data is supportive of advancement to a therapeutic Phase I/II study in H2 2024.

MELBOURNE, Australia, May 21, 2024 (GLOBE NEWSWIRE) -- Telix Pharmaceuticals Limited (ASX: TLX, Telix, the Company) today announces the successful completion of CUPID¹, a first-in-human Phase I dose escalation study of TLX592 in patients with advanced prostate cancer.

TLX592 (²²⁵Ac-PSMA-RADmAb®) is Telix’s investigational “next generation” targeted alpha therapy (TAT) for the treatment of prostate cancer and is the first clinical program to utilise Telix’s proprietary RADmAb® engineered antibody technology. The RADmAb® approach accelerates blood clearance and reduces bone marrow residence time compared with standard monoclonal antibodies (mAbs), while retaining target selectivity, internalisation and retention. The RADmAb® platform is currently under pre-clinical and clinical evaluation for multiple cancer targets.

The CUPID (⁶⁴CuPSMA Imaging and (Bio) Distribution) study is a 3+3 mass dose escalation study with four patient cohorts intended to evaluate the safety, tolerability, pharmacokinetics, biodistribution and radiation dosimetry of TLX592. The study utilises copper-64 (⁶⁴Cu) which is detectable by Positron Emission Tomography (PET) as a surrogate for actinium-225 (²²⁵Ac), enabling a successful proof-of-targeting study as well as predictive dosimetry calculations for future studies with ²²⁵Ac. Preliminary results in 11 evaluable patients enrolled in the study demonstrated accelerated blood kinetics compared to the standard antibody TLX591, while demonstrating similar (favourable) on-target and off-target biodistribution and hepatic clearance. There were no serious adverse events observed in the study.

Based on these encouraging results, Telix expects to advance TLX592 into a therapeutic Phase I/II study with ²²⁵Ac in the second half of 2024, subject to regulatory approval. TLX592 further deepens Telix’s PSMA²-targeting prostate cancer therapy portfolio and supplements its lead investigational radio antibody-drug conjugate (rADC) TLX591 (177Lu rosopatamab tetraxetan), currently being investigated in the ProstACT GLOBAL Phase III study. The Company intends to publish and present non-clinical and clinical data supporting these results at several upcoming symposia.

Dr David N. Cade, Group Chief Medical Officer at Telix stated, “The CUPID study demonstrated clearly how theranostic approaches can be used to streamline novel radiopharmaceutical drug development. In this case, PET imaging was used to dose-find a targeting agent for future use with an alpha emitter, while establishing basic safety and utility parameters that will greatly inform ongoing development of this product candidate.

“There is a significant unmet need for novel targeting platforms that may be used with alpha emitting isotopes and avoid renal toxicity and other off-target effects, such as the exocrine gland uptake typical of PSMA small molecule agents. We are excited to progress TLX592 into therapeutic studies where our aim is to develop this agent for both early metastatic prostate cancer and late-stage patients who are no longer responding to lutetium therapy. We would like to thank all participants for their commitment to the CUPID study.”

________________________
_{¹ ClinicalTrials.gov ID: NCT04726033.
² Prostate-specific membrane antigen.}

About Telix Pharmaceuticals Limited
Telix is a biopharmaceutical company focused on the development and commercialisation of diagnostic and therapeutic radiopharmaceuticals and associated medical devices. Telix is headquartered in Melbourne, Australia, with international operations in the United States, Europe (Belgium and Switzerland), and Japan. Telix is developing a portfolio of clinical and commercial stage products that aims to address significant unmet medical needs in oncology and rare diseases. Telix is listed on the Australian Securities Exchange (ASX: TLX).

Telix’s lead imaging product, gallium-68 (⁶⁸Ga) gozetotide injection (also known as ⁶⁸Ga PSMA-11 and marketed under the brand name Illuccix®), has been approved by the U.S. Food and Drug Administration (FDA)³, by the Australian Therapeutic Goods Administration (TGA) ⁴, and by Health Canada⁵. No other Telix product has received a marketing authorisation in any jurisdiction.

Visit www.telixpharma.com for further information about Telix, including details of the latest share price, announcements made to the ASX, investor and analyst presentations, news releases, event details and other publications that may be of interest. You can also follow Telix on X and LinkedIn.

________________________
_{³ Telix ASX disclosure 20 December 2021.
⁴ Telix ASX disclosure 2 November 2021.
⁵ Telix ASX disclosure 14 October 2022.}

Telix Investor Relations

Ms. Kyahn Williamson
Telix Pharmaceuticals Limited
SVP Investor Relations and Corporate Communications
Email: kyahn.williamson@telixpharma.com

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

Legal Notices

The information contained in this announcement is not intended to be an offer for subscription, invitation or recommendation with respect to shares of Telix Pharmaceuticals Limited (Telix) in any jurisdiction, including the United States. 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. The information contained in this announcement is subject to change without notification.

This announcement may contain forward-looking statements 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”, “outlook”, “forecast” and “guidance”, or other similar words. 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 the Company’s good-faith assumptions as to the financial, market, regulatory and other risks and considerations that exist and affect the Company’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 and results of Telix’s preclinical and clinical studies, and Telix’s research and development programs; Telix’s ability to advance product candidates into, enrol and successfully complete, clinical studies, including multi-national clinical trials; the timing or likelihood of regulatory filings and approvals, manufacturing activities and product marketing activities; the commercialisation of Telix’s product candidates, if or when they have been approved; estimates of Telix’s expenses, future revenues and capital requirements; Telix’s financial performance; developments relating to Telix’s competitors and industry; 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. You should read this announcement together with our risk factors, as disclosed in our most recently filed reports with the ASX or on our website.

To the maximum extent permitted by law, Telix disclaims any obligation or undertaking to publicly update or revise any forward-looking statements contained in this announcement, whether as a result of new information, future developments or a change in expectations or assumptions.

©2024 Telix Pharmaceuticals Limited. The Telix Pharmaceuticals® and Illuccix® names and logos are trademarks of Telix Pharmaceuticals Limited and its affiliates – all rights reserved.