Telix Pharmaceuticals Limited announced highly positive top-line results from the pivotal Phase III ZIRCON study (Zirconium in Renal Cancer Oncology, NCT03849118) of its investigational renal (kidney) cancer positron emission tomography (PET) imaging agent, TLX250-CDx (89Zr-DFO-girentuximab). The study has met its co-primary and secondary endpoints. The study results delivered 86% sensitivity and 87% specificity, exceeding the pre-determined threshold required to demonstrate the ability of TLX250-CDx to reliably detect the clear cell phenotype and provide a non-invasive method of diagnosing the presence and spread of ccRCC.

The study has also met the key secondary endpoint, achieving 85% sensitivity and 89% specificity in detecting ccRCC in tumours <4cm ("T1a" classification), currently a significant clinical challenge in the diagnosis of ccRCC. A total of 300 patients were dosed with TLX250-CDx resulting in 284 evaluable patients. Each patient received a single dose of TLX250-CDx and a histological tumour sample from surgical resection was used as the truth comparator.

The results mean that, for the first time, urologists and urologic oncologists may have a non-invasive way to determine if small renal masses are the clear cell phenotype, the most aggressive and common form of renal malignancy. TLX250-CDx has received "Breakthrough Designation" from the FDA.