According to results from a phase 3 trial, radiolabeled ⁸⁹Zr-DFO-girentuximab (TLX250-CDx) PET/CT was found to identify clear cell renal cell carcinoma accurately and noninvasively.

Brian Shuch, MD, David Geffen School of Medicine at University of California — Los Angeles, CA, presented results on Saturday, February 18, 2023, at the 2023 ASCO Genitourinary Cancers Symposium in San Francisco, CA.

The open-label, multicenter ZIRCON trial enrolled 300 patients with an indeterminate renal mass of ≤7cm at cT1a who were scheduled to undergo a partial nephrectomy within 90 days of planned TLX250-CDx administration. All patients received a single dose of TLX250-CDx on day 0, followed by PET/CT imagining on day 5 prior to surgery.

The coprimary objectives were evaluation of both the sensitivity and specificity of TLX250-CDx PET/CT imaging in detecting clear cell renal cell carcinoma among patients with an indeterminate renal mass. Blinded central histology review was used as the standard of truth for clear cell renal cell carcinoma status. Key secondary objectives were the sensitivity and specificity of TLX250-CDx PET/CT imaging among patients with an indeterminate renal mass of ≤4cm (cT1a) while other secondary objectives included positive and negative prediction values, safety, and tolerability.

There were 288 patients with central histopathology of surgical samples, of which 193 (67%) had clear cell renal cell carcinoma and 179 (62%) had cT1a. There were 284 evaluable patients included in the primary analysis.

Of the 3 readers for sensitivity the average was 86% and for specificity the average was 87%. Among the subgroup of patients with a mass of ≤4cm, the average sensitivity was 85% and the average sensitivity was 90%. Positive predictive values were ≥91.7% and negative predictive values were ≥73.7%. There were 263 treatment-emergent adverse events, of which 2 were determined to be treatment-related.

Dr Shuch and coauthors concluded, “TLX250-CDx PET/CT is well tolerated and can accurately and noninvasively identify [clear cell renal cell carcinoma], with promising utility for designing best management approaches for patients with [indeterminate renal masses].”

Source:

Shuch B, Pantuck AJ, Bernhard JC, et al. Results from phase 3 study of ⁸⁹Zr-DFO-girentuximab for PET/CT imaging of clear cell renal cell carcinoma (ZIRCON). Presented at the 2023 ASCO Genitourinary Cancers Symposium; February 16-18, 2023; San Francisco, CA. Abstract LBA602