TLX591 is an investigational anti-PSMA[1] radio-antibody-drug conjugate rADC therapy being developed for the treatment of mCRPC differentiated by a short two-week dosing regimen Reported median radiographic progression-free survival rPFS is 88 months Builds on prior data from the ProstACT SELECT[2] trial demonstrating favourable safety profile and biodistribution[3] MELBOURNE Australia May 31 2024 PRNewswire --Telix Pharmaceuticals Limited ASX TLX Telix the Company today announces additional positive datafrom the ProstACT SELECT trial SELECT of TLX591 177Lu rosopatamab tetraxetan a lutetium-labelled rADC therapy for the treatment of adult patients with PSMA-positive metastatic castrate-resistant prostate cancer mCRPC SELECT is a radiogenomics study intended to evaluate lesion concordance between 68Ga gallium-based PSMA-PET[4] imaging and TLX591 dosimetry for the purpose of validating PET imaging for patient selection for rADC therapy The Company has previously reported final safety data from this study3 The study has reported a median rPFS of 88 months representing an encouraging signal of the potential efficacy of TLX591 in this patient population The evaluable sample size for rPFS comprised 23 patients with previously treated progressive mCRPC and who received two 76 mCi intravenous IV infusions of TLX591 14 days apart[5] The SELECT trial included a heterogeneous population of low medium and high disease burden patients to facilitate imaging cross-comparison with the majority having undergone two prior lines of therapy Nat Lenzo MD Nuclear Oncologist and General Internal Medicine Physician and lead recruiter onto the SELECT trial commented We are encouraged by this rPFS result which compares favourably to small molecule radioligand therapy RLT Phase I and II studies at similar stages of development[6] This is a compelling signal of the potential efficacy of TLX591 in this heavily pre-treated population The results further support the development of this candidate in an earlier mCRPC patient population which is the focus of the ProstACT GLOBAL[7] Phase III trial and where there remains significant unmet need for effective treatment Dr David N Cade MD Group Chief Medical Officer at Telix stated TLX591 is a radio-ADC with significant potential advantages compared to small molecule radiopharmaceuticals in treating prostate cancer TLX591 is differentiated by a patient-friendly dosing regimen with far lower cumulative radiation exposure compared to small molecule radioligand therapies[8] This positive signal of efficacy from SELECT builds on prior studies that demonstrated the potential for TLX591 to deliver improved quality of life and durable tumour control in this advanced patient population[9] TLX591 is being further evaluated in the Phase III ProstACT GLOBAL trial in first and second line mCRPC which is now preparing to enrol patients at its first US sites This innovative trial design allowsphysicians a choice of androgen receptor inhibition or docetaxel chemotherapy thus integrating with real-world standard of care reflective of Telix continued innovation in prostate cancer care and commitment to patient outcomes About TLX591 TLX591 INN lutetium Lu 177 rosopatamab tetraxetan is Telix lead investigational radio antibody-drug conjugate rADC for the treatment of mCRPC composed of a high-specificity PSMA-targeting antibody chelator linker and cytotoxic lutetium 177Lu payload TLX591 is administered intravenously under a two-dose fractionated regimen potentially enabling the delivery of a highly targeted and potent dose with improved off-target organ radiation exposure The mAb-based approach may offer distinct advantages in selectivity internalisation and retention time over small molecule RLTs for the treatment of mCRPC A total of 242 patients have been treated with TLX591 across eight Phase I and Phase II trials9including a previously published Phase II open-label single-arm trial which reported a 423 month OS in 17 patients with advanced mCRPC when TLX591 was delivered under a fractionated dosing regimen[10] About ProstACT SELECT The purpose of the ProstACT SELECT trial is to evaluate the utility of PSMA-PET imaging with Illuccix to select patients for TLX591 rADC therapy The primary objectives are to determine whole body biodistribution and organ radiation dosimetry and assess the safety and tolerability of TLX591 in patients with advanced mCRPC Radiographic progression-free survival rPFS is a secondary study objective Previously reported data from the SELECT trial includes3 Confirmation of biodistribution and safety profile with a low rate of off-target side effects Confirmation of internalisation and long retention delivering a payload to the tumour potentially maximising cell killing effect Lower rates of haematologic toxicity than prior later-line studies of TLX591 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 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 US Food and Drug Administration FDA[11] by the Australian Therapeutic Goods Administration TGA[12] and by Health Canada[13] No other Telix product has received a marketing authorisation in any jurisdiction Visit wwwtelixpharmacom 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 XandLinkedIn Telix Investor Relations Ms Kyahn Williamson Telix Pharmaceuticals Limited SVP Investor Relations and Corporate Communications Email kyahnwilliamson@telixpharmacom 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 good-faith assumptions as to the financial market regulatory and other risks and considerations that exist and affect the Company 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 business forward-looking statements may include but are not limited to statements about the initiation timing progress and results of Telix preclinical and clinical studies and Telix research and development programs Telix ability to advance product candidates into enrol and successfully complete clinical studi