Daniel Canter, MD, on the potential impact of 89Zr-girentuximab in kidney cancer

⁸⁹Zr-girentuximab (TLX250-CDx; Zircaix) is currently under FDA review for PET imaging of clear cell renal cell carcinoma (ccRCC), with a PDUFA target action date of August 27, 2025. The FDA granted priority review to the application for ⁸⁹Zr-girentuximab in February 2025.¹

In a recent interview with Urology Times®, Daniel Canter, MD, outlined the potential impact of the agent, if approved. Canter is a urologic oncologist at Georgia Urology in Atlanta.

The phase 3 ZIRCON trial (NCT03849118), which is supporting the application for ⁸⁹Zr-girentuximab, enrolled 300 patients with an indeterminate renal mass of 7 cm or smaller that was suspicious for ccRCC.² Data showed an average sensitivity of 85.5% (95% CI, 81.5 to 89.6) and an average specificity of 87% (95% CI, 81.0 to 93.1) across 3 independent readers in detecting ccRCC.

However, Canter noted that where he sees the most promising application for this agent is in those patients with a renal mass of 4cm or smaller.

“From historic cohorts, when you use CT scanning [in] the less than 4 cm masses, you can sometimes have issues with the sensitivity and specificity,” he explained. “When you're using an agent like the CAIX PET scan, I think it will help to determine which patients have clear cell kidney cancer, or small clear cell cancer, and which ones do not.”

In the ZIRCON trial, ⁸⁹Zr-girentuximab had an average sensitivity of 85.0% (95% CI, 81.8 to 88.1) and an average specificity of 89.5% (95% CI, 84.2 to 94.8) in patients with small renal masses.

REFERENCES

1. FDA accepts BLA for TLX250-CDx (Zircaix) for kidney cancer imaging, grants priority review. News release. Telix Pharmaceuticals. February 25, 2025. Accessed August 21, 2025. https://telixpharma.com/news-views/fda-accepts-bla-for-tlx250-cdx-zircaix-for-kidney-cancer-imaging-grants-priority-review/

2. Shuch B, Pantuck AJ, Bernhard JC, et al. [89Zr]Zr-girentuximab for PET–CT imaging of clear-cell renal cell carcinoma: a prospective, open-label, multicentre, phase 3 trial. Lancet Oncol. 2024;25(10):1277-1287. doi:10.1016/S1470-2045(24)00402-9