TLX250-CDx, which has received "Breakthrough Designation" from the U.S. Food and Drug Administration (FDA)¹, is being developed as an imaging agent for use in the characterization of indeterminate renal masses previously identified on computed tomography (CT) or magnetic resonance imaging (MRI) as clear cell renal cell cancer (ccRCC) or non-ccRCC.

The detection of renal masses is increasing due to widespread use of cross-sectional imaging. Many of these are small renal masses and represent a diagnostic challenge as current imaging cannot reliably distinguish benign or malignant lesions from renal cell carcinoma, leading to invasive biopsy or partial nephrectomy to confirm the diagnosis. These procedures are not always necessary and can lead to complications². It is estimated that up to 80% of small renal masses are malignant³.

If the study is successful, TLX250-CDx may provide a non-invasive method to aid in diagnosis and staging of ccRCC and the identification of metastatic disease through whole body imaging, ultimately leading to improved patient management by minimizing the need for surgical intervention for diagnosis and guiding treatment decisions.

In addition to its potential use as a diagnostic and staging tool, Telix is considering the potential for TLX250-CDx to also be used as an active surveillance tool for patients not deemed surgical candidates.

Brian M Shuch, MD, Director of the Kidney Cancer program at UCLA said: "We may well be on the cusp of a paradigm shift in how we manage renal masses. The incidence of small renal masses is increasing, yet there is currently no imaging tool that can effectively diagnose or stage clear cell renal cancer. Most patients are scheduled for the operating room without a firm diagnosis and often surgery is found to be unnecessary. Should this study report positive results, it may provide the non-invasive imaging tool to aid in accurate diagnosis that patients and clinicians have been waiting for. Congratulations to Telix for completing this ambitious international trial."

Renal cell carcinoma (RCC) is the deadliest of all urological cancers with a late-stage 5-year survival rate of 14%⁴. ccRCC is the most common sub-type and accounts for approximately 80% of all renal cell carcinoma cases⁵. RCC is also an increasingly frequent cancer, having more than doubled in incidence in the developed world over the last 50 years.⁶ Worldwide, there were more than 400,000 new cases in 2020, and >175,000 people died from their disease.⁷

TLX250-CDx will be available in selected countries to eligible patients under an Expanded Access Program (EAP) (also known as early access, pre-approval access or emergency use), in accordance with Telix's Compassionate Use Policy and subject to jurisdictional regulatory requirements.⁸

Dr Colin Hayward, Telix's Chief Medical Officer said, "The completion of this trial will bring us a step closer to commercialization for this diagnostic imaging agent which may address a significant unmet need in the diagnosis and management of ccRCC. It also builds on Telix's commitment to urologic oncology, with the potential of delivering a major new imaging indication. This milestone could have not been achieved without the support of our many collaborators including the 36 clinical sites who participated in the trial, our global manufacturing teams and the associated auxiliary team who have supported this study. Most of all we wish to thank the patients who have volunteered to participate in this study."

ZIRCON is a confirmatory, prospective, open-label, multi-centre phase III study to evaluate sensitivity and specificity of ⁸⁹Zr-TLX250-CDx PET/CT imaging to non-invasively detect clear cell renal cell cancer (ccRCC) in adult patients with indeterminate renal masses (IDRM), scheduled for partial or total nephrectomy. Telix expects to report the outcome from the ZIRCON study in 2H, 2022.