On February 25, 2025 Telix Pharmaceuticals Limited (ASX: TLX, Nasdaq: TLX, Telix, the Company) reported that the United States (U.S.) Food and Drug Administration (FDA) has accepted the Biologics License Application (BLA) for its breakthrough investigational kidney cancer PET[1] imaging agent TLX250-CDx (Zircaix[2], 89Zr-DFO-girentuximab), granted a Priority Review and provided a PDUFA[3] date of 27 August 2025, paving the way for a U.S. commercial launch in 2025 (Press release, Telix Pharmaceuticals, FEB 25, 2025, View Source [SID1234650553]).
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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 ZIRCON[4] 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 lesions[5]. 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 colleagues[6]. 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/CT[7] scanning has changed the management of prostate cancer. By providing a more definitive clinical diagnosis for renal masses, we believe that Zircaix[2] 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 2025[8]."
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 readers[5]. 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.