FDA Accepts Priority Review for TLX250-CDx Kidney Cancer Imaging

Telix Pharmaceuticals Limited, headquartered in Melbourne, Australia, announced that the U.S. Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) for TLX250-CDx, a groundbreaking investigational PET imaging agent for kidney cancer. The FDA granted Priority Review to this application and established a Prescription Drug User Fee Act (PDUFA) date of August 27, 2025. If approved, this move positions Telix for a U.S. commercial launch in 2025.

TLX250-CDx, branded as Zircaix®, is poised to become the first commercially available imaging agent capable of accurately diagnosing and characterizing clear cell renal cell carcinoma (ccRCC), the most prevalent and aggressive form of kidney cancer. This innovative agent targets carbonic anhydrase IX (CAIX), a protein found on 95% of ccRCC cells, enabling high-resolution imaging with excellent specificity and consistency.

The BLA's acceptance is supported by the results of Telix’s pivotal global Phase 3 ZIRCON study, which demonstrated the agent's impressive performance metrics: 86% sensitivity, 87% specificity, and a 93% positive predictive value in detecting ccRCC, even in small and challenging-to-detect lesions. The findings were published in The Lancet Oncology in September 2024 by Professor Brian Shuch from the University of California, Los Angeles, and his colleagues. They highlighted the pressing need for a non-invasive method capable of accurately distinguishing ccRCC from other renal masses, concluding that TLX250-CDx fulfills this requirement and has the potential to transform clinical practice.

Kevin Richardson, CEO of Precision Medicine at Telix, expressed enthusiasm over the FDA's acceptance, noting that it brings the company closer to introducing their revolutionary product to patients. Richardson emphasized that the new imaging agent aims to enhance kidney cancer management similarly to how PSMA-PET/CT scanning has improved prostate cancer care. By providing precise clinical diagnoses for renal masses, Zircaix® is expected to empower physicians to make timely and informed decisions, offering patients a clearer understanding of their condition and available treatments. This development builds on Telix's successful urology franchise as the company prepares for a market launch in 2025.

TLX250-CDx's success in the Phase 3 ZIRCON trial, which involved 300 patients, with 284 providing evaluable results, underscores its ability to reliably detect the clear cell phenotype. The trial met all primary and secondary endpoints, confirming the agent's high accuracy and consistent interpretation across three independent radiology readers. The confidence intervals exceeded expectations, showcasing the agent's reliable diagnostic capabilities.

In its commitment to broadening access to medicine, Telix operates an expanded access program (EAP) in the U.S., named patient programs (NPPs) in Europe, and a special access scheme (SAS) in Australia. These programs allow patients without comparable or satisfactory alternative options to access TLX250-CDx outside of clinical trials. At present, TLX250-CDx remains investigational and has not received marketing authorization in any jurisdiction.

Telix Pharmaceuticals Limited is a biopharmaceutical company specializing in the development and commercialization of diagnostic and therapeutic radiopharmaceuticals and related medical technologies. With headquarters in Melbourne, Telix has international operations in the U.S., Canada, Europe, and Japan. The company aims to address significant unmet medical needs in oncology and rare diseases through its portfolio of clinical and commercial stage products.