Patient enrollment has been completed in the phase 3 ZIRCON trial (NCT03849118) exploring TLX250-CDx (89Zr-DFO-girentuximab), a novel PET imaging radiopharmaceutical for clear cell renal cell carcinoma (RCC).1
The goal of the ZIRCON trial is to establish the efficacy of TLX250-CDx as a noninvasive tool to identify clear cell RCC in patients with indeterminate renal masses identified on CT or MRI. To date, 300 patients have been dosed in the trial, exceeding the targeted enrollment of 252 patients. The primary outcome measures of the study are sensitivity and specificity.
The FDA granted a Breakthrough Therapy Designation to TLX250-CDx in July 2020 for the diagnosis and staging of indeterminate renal masses.2 The designation is intended to expedite the development and regulatory review of the imaging radiopharmaceutical in this setting.
"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," Brian M Shuch, MD, director of the Kidney Cancer program at UCLA, stated in a press release.
TLX250-CDx uses the anti-CAIX monoclonal antibody girentuximab to target the cell-surface antigen CAIX. The antigen is found on over 90% of clear cell RCC cells, but is not found in normal kidney cells. CAIX is also expressed in metastatic disease, and Telix suggests this might enhance the accuracy of staging patients with clear cell RCC.
The prospective, international, open-label, single-group assignment, phase 3 ZIRCON trial is exploring TLX250-CDx in patients with indeterminate renal masses scheduled for partial or total nephrectomy. The indeterminant renal mass must be a maximum of 7 cm in largest diameter (tumor stage cT1) and the nephrectomy must occur within 90 days of the administration of TLX250-CDx.3 The efficacy of TLX250-CDx will be determined through a comparison with histologic results with surgical resection as the “standard of truth.”
The study is being conducted at 36 locations in Europe, Australia, Turkey, Canada, and the United States. The targeted enrollment is 252 patients and the estimated primary completion date is May 31, 2021.
Telix has other imaging products in its pipeline, including TLX591-CDx, a radiopharmaceutical cold kit for the rapid preparation of 68Ga-PSMA-11 injection for PET imaging in prostate cancer. The company has submitted a new drug application to the FDA for TLX591-CDx.4
1. ZIRCON Phase III Kidney Cancer Imaging Study Completes Enrolment. Published online July 12, 2022. Accessed July 12, 2022. https://prn.to/3ALB3Bs
2. Telix Granted FDA Breakthrough Therapy Designation for Renal Cancer Imaging Product. Published online July 1, 2020. Accessed January 25, 2021. https://bit.ly/39hkIpT.
3. NIH US National Library of Medicine ClinicalTrials.gov. 89Zr-TLX250 for PET/CT Imaging of ccRCC- ZIRCON Study (89ZR-TLX250). Last updated October 19, 2020. Accessed January 25, 2021. https://clinicaltrials.gov/ct2/show/NCT03849118
4. Telix pharmaceuticals submits new drug application to US FDA for prostate cancer imaging product. Published September 24, 2020. Accessed January 25, 2021. https://bit.ly/305aT9v.