FDA Accepts BLA for TLX250-CDx (Zircaix®) for Kidney Cancer Imaging, Grants Priority Review

Rhea-AI Summary

Telix Pharmaceuticals (ASX/Nasdaq: TLX) announces FDA acceptance of Biologics License Application (BLA) for TLX250-CDx (Zircaix®), their kidney cancer PET imaging agent, with Priority Review status and PDUFA date of August 27, 2025.

TLX250-CDx is positioned to become the first commercially available imaging agent for accurate, non-invasive diagnosis of clear cell renal cell carcinoma (ccRCC). The technology targets carbonic anhydrase IX (CAIX), expressed on 95% of ccRCC cells.

The BLA submission is supported by the Phase 3 ZIRCON study results, showing 86% sensitivity, 87% specificity, and 93% positive predictive value for ccRCC detection. The study results, published in The Lancet Oncology (September 2024), highlight the product's potential to revolutionize kidney cancer management similar to PSMA-PET/CT's impact on prostate cancer diagnostics.

Positive

• FDA grants Priority Review status for TLX250-CDx
• Strong Phase 3 trial results: 86% sensitivity, 87% specificity
• 93% positive predictive value in detecting ccRCC
• First-to-market potential in kidney cancer imaging
• Targets protein expressed in 95% of ccRCC cells

Negative

• Commercial launch not expected until late 2025
• FDA approval still pending

Insights

Financial Analyst

The FDA's acceptance of Telix's BLA for TLX250-CDx (Zircaix®) with Priority Review represents a significant catalyst for the company's near-term growth trajectory. With a PDUFA date of August 27, 2025, Telix is positioning for commercial launch in Q4 2025, potentially adding a valuable revenue stream to complement its established urology franchise.

The kidney cancer imaging market represents a substantial opportunity. Approximately 79,000 new kidney cancer cases are diagnosed annually in the U.S. alone, with ccRCC accounting for roughly 70% of cases. Current diagnostic approaches rely heavily on invasive biopsies or imprecise imaging, creating a clear market need that Zircaix addresses directly.

The product's impressive clinical profile (86% sensitivity, 87% specificity, 93% PPV) published in The Lancet Oncology establishes strong differentiation. Drawing parallels to PSMA-PET imaging for prostate cancer is particularly telling - that technology rapidly transformed standard of care and generated significant revenue for early market entrants.

From a commercialization perspective, Telix can leverage its existing urology sales infrastructure, potentially accelerating market penetration while controlling launch costs. Medicare reimbursement pathways for novel radiopharmaceuticals have improved substantially, reducing a key adoption barrier.

The Priority Review designation reduces regulatory uncertainty and shortens time-to-market, though manufacturing scale-up and distribution of the zirconium-89 based tracer will present logistical challenges due to its 78-hour half-life. This technical complexity may actually serve as a competitive moat, extending Telix's first-mover advantage in this specialized market segment.

Oncology Expert

The FDA's Priority Review acceptance for TLX250-CDx (Zircaix®) represents a potential paradigm shift in kidney cancer management. This PET imaging agent targets carbonic anhydrase IX (CAIX), which is expressed on 95% of clear cell renal cell carcinoma (ccRCC) cells but absent in most benign renal masses and other RCC subtypes, creating an ideal biomarker for non-invasive differentiation.

The clinical implications are substantial. Currently, approximately 20-30% of surgically removed small renal masses prove benign on pathology, representing unnecessary surgical interventions. TLX250-CDx's 87% specificity could significantly reduce these surgeries, preserving renal function and avoiding surgical complications.

For indeterminate small renal masses (<4cm), this technology could transform management pathways. Rather than choosing between immediate surgery or the anxiety of watchful waiting with serial imaging, clinicians could use TLX250-CDx to confidently identify which masses require intervention versus those appropriate for active surveillance.

The technology's ability to detect small lesions is particularly valuable for patients with hereditary syndromes like Von Hippel-Lindau disease, who develop multiple renal tumors and face cumulative renal function loss from repeated surgeries.

Beyond initial diagnosis, TLX250-CDx may prove valuable for treatment response assessment. The CAIX target remains stable during treatment, potentially allowing clinicians to distinguish between post-treatment changes and residual viable tumor - a significant challenge with conventional imaging.

While implementation will require nuclear medicine department coordination and radiologist training, the clinical workflow integration should be straightforward given the established infrastructure for other PET tracers. The 78-hour half-life of zirconium-89 provides a practical window for centralized production and distribution to regional medical centers.

MELBOURNE, Australia and INDIANAPOLIS, Feb. 26, 2025 (GLOBE NEWSWIRE) -- Telix Pharmaceuticals Limited (ASX: TLX, Nasdaq: TLX, Telix, the Company) today announces that the United States (U.S.) Food and Drug Administration (FDA) has accepted the Biologics License Application (BLA) for its breakthrough investigational kidney cancer PET¹ imaging agent TLX250-CDx (Zircaix®², ⁸⁹Zr-DFO-girentuximab), granted a Priority Review and provided a PDUFA³ date of 27 August 2025, paving the way for a U.S. commercial launch in 2025.

If approved, TLX250-CDx will become the first commercially available imaging agent to accurately and non-invasively diagnose and characterize clear cell renal cell carcinoma (ccRCC), the most common and one of the most aggressive sub-types of kidney cancer. It works by specifically binding to carbonic anhydrase IX (CAIX), a validated target protein expressed on 95% of ccRCC cells to produce images with high tumor-to-background ratio and high intra- and inter-reader consistency.

The BLA is based on Telix’s successful global Phase 3 ZIRCON⁴ study, which demonstrated a sensitivity of 86%, specificity of 87% and a positive predictive value (PPV) of 93% for ccRCC, including in very small, difficult-to-detect lesions⁵. The results of this study were published in The Lancet Oncology in September 2024, in a peer-reviewed manuscript by Professor Brian Shuch (University of California, Los Angeles, UCLA) and colleagues⁶. The paper outlines the critical unmet need for a new, non-invasive technique that can accurately detect and differentiate ccRCC from other renal masses in patients and concluded that TLX250-CDx meets this need and ‘has the potential to be practice changing.’ 

Kevin Richardson, Chief Executive Officer, Precision Medicine, said, “We are delighted that the FDA has accepted this BLA as it moves us one step closer to bringing our breakthrough product to patients. We are aiming to revolutionize the management of kidney cancer, just as PSMA-PET/CT⁷ scanning has changed the management of prostate cancer. By providing a more definitive clinical diagnosis for renal masses, we believe that Zircaix² will help physicians make more timely and confident patient management decisions and more quickly provide patients with a clear understanding of their disease and treatment options. Building further on Telix’s successful urology franchise, we are preparing to bring this powerful precision medicine product to market in 2025⁸.”

About TLX250-CDx

TLX250-CDx (Zircaix®²) is an investigational PET agent that is under development for the diagnosis and characterization of ccRCC. Telix’s pivotal Phase 3 ZIRCON trial evaluating TLX250-CDx in 300 patients, of whom 284 were evaluable, met all primary and secondary endpoints, including showing 86% sensitivity and 87% specificity and a 93% PPV for ccRCC across three independent radiology readers⁵. Telix believes this demonstrated the ability of TLX250-CDx to reliably detect the clear cell phenotype and provide an accurate, non-invasive method for diagnosing and characterizing ccRCC. Confidence intervals exceeded expectations amongst all three readers, showing evidence of high accuracy and consistency of interpretation. 

As part of Telix’s commitment to access to medicine, the Company operates an expanded access program (EAP) in the U.S.⁹, named patient programs (NPPs) in Europe, and a special access scheme (SAS) in Australia to allow continued access to TLX250-CDx outside of a clinical trial, to patients for whom there are no comparable or satisfactory alternate options. TLX250-CDx has not received a marketing authorization in any jurisdiction and is for investigational use only.

About Telix Pharmaceuticals Limited

Telix is a biopharmaceutical company focused on the development and commercialization of therapeutic and diagnostic radiopharmaceuticals and associated medical technologies. Telix is headquartered in Melbourne, Australia, with international operations in the United States, Canada, 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. ARTMS, IsoTherapeutics, Lightpoint, Optimal Tracers and RLS are Telix Group companies. 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 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

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

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 and results of Telix’s preclinical and clinical trials, 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 for Telix’s product candidates, manufacturing activities and product marketing activities; Telix’s sales, marketing and distribution and manufacturing capabilities and strategies; the commercialisation 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; 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.

©2025 Telix Pharmaceuticals Limited. Telix Pharmaceuticals®, Telix Group company, and Telix product names and logos are trademarks of Telix Pharmaceuticals Limited and its affiliates – all rights reserved. Trademark registration status may vary from country to country.

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¹ Positron emission tomography.
² Brand name subject to final regulatory approval. 
³ Prescription Drug User Fee Act.   
⁴ Zirconium in Renal Cancer Oncology, ClinicalTrials.gov ID: NCT03849118.
⁵ Telix ASX disclosures 7 November 2022.
⁶ Shuch et al. Lancet Oncology. 2024.
⁷ Imaging of prostate-specific membrane antigen with positron emission tomography/computed tomography.
⁸ Subject to regulatory approval.
⁹ ClinicalTrials.gov ID: NCT06090331.

FAQ

What are the success rates of TLX250-CDx in detecting kidney cancer?

TLX250-CDx demonstrated 86% sensitivity, 87% specificity, and 93% positive predictive value in detecting clear cell renal cell carcinoma (ccRCC) during Phase 3 trials.

When is the FDA expected to make a decision on TLX's kidney cancer imaging agent?

The FDA's PDUFA date for TLX250-CDx is August 27, 2025.

How does TLX250-CDx work in detecting kidney cancer?

It binds to carbonic anhydrase IX (CAIX), a protein expressed on 95% of ccRCC cells, producing high-quality imaging for non-invasive cancer detection.

What makes TLX250-CDx unique in kidney cancer diagnosis?

It's positioned to be the first commercially available imaging agent for non-invasive diagnosis and characterization of clear cell renal cell carcinoma.

Where were the Phase 3 ZIRCON study results for TLX published?

The results were published in The Lancet Oncology in September 2024.