NEW YORK – Telix Pharmaceuticals on Monday said it will seek regulatory approval for its PET imaging agent TLX250-CDx (Zr-89-DFO-girentuximab) as a tool for distinguishing between benign and malignant renal masses based on positive results from the Phase III ZIRCON trial.
In the trial, 300 patients with a renal mass received a single administration of the agent followed by PET/CT imaging about five days later. The imaging agent-based diagnosis of clear cell renal cell carcinoma (ccRCC) was then compared to traditional diagnosis based on a histological tumor sample. Doctors could perform a nephrectomy on patients after the PET/CT imaging at their discretion. The investigators found that TLX250-CDx had 86 percent sensitivity and 87 percent specificity for noninvasively detecting ccRCC.
Telix plans to file a biologics license application with the US Food and Drug Administration and seek marketing authorization from global regulatory agencies for TLX250-CDx as a PET/CT imaging agent that can characterize indeterminate renal masses. It anticipates that in the future the product could be used for surveillance, surgical staging, and treatment response assessment.
TLX250-CDx targets carbonic anhydrase IX (CAIX or CA9), a surface antigen expressed by ccRCC cells. According to Telix, detection of renal masses is increasing due to more frequent use of cross-sectional imaging. Because current imaging methods do not reliably distinguish benign masses from malignant renal cell carcinoma, patients are being unnecessarily subjected to invasive surgical procedures.
The Melbourne, Australia-based company is also conducting a Phase II trial of TLX250-CDx in triple-negative breast cancer. That trial will assess how well the agent can diagnose and stage patients and whether CA9 would be suitable as a radiotherapeutic in the future.
In 2021, the FDA approved Illuccix (TLX591-CDx), an imaging agent Telix markets for the identification of prostate-specific membrane antigen-positive prostate cancer lesions.