A novel imaging technique, 89Zr-DFO-girentuximab PET/CT, can accurately and noninvasively identify clear cell renal cell carcinoma (ccRCC), according to research presented at the 2023 ASCO Genitourinary Cancers Symposium.
89Zr-DFO-girentuximab PET/CT improves the identification of ccRCC compared with conventional cross-sectional imaging metrics, said study presenter Brian M. Shuch, MD, of the University of California, Los Angeles.
Dr Shuch and colleagues tested 89Zr-DFO-girentuximab PET/CT in the phase 3 ZIRCON trial (ClinicalTrials.gov Identifier: NCT03849118). The trial included 300 patients with indeterminate renal masses (IDRMs ; ≤7 cm; tumor stage cT1) who were scheduled for partial nephrectomy within 90 days of 89Zr-DFO-girentuximab administration.
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The patients’ median age was 62 years (range, 27-87), and 71.3% were men. Of 288 patients with evaluable surgical samples, 193 patients (67%) had ccRCC, and 179 patients (62%) had CT1a lesions.
The patients received a single dose of 89Zr-DFO-girentuximab intravenously (37 MBq ± 10%; 10 mg girentuximab) on day 0 and underwent PET/CT on day 5 (± 2 days) before surgery.
The coprimary endpoints of this study were the sensitivity and specificity of 89Zr-DFO-girentuximab PET/CT in detecting ccRCC in patients with IDRMs, as assessed by 3 independent readers. Among 284 evaluable patients, the sensitivity was 85.5%, and the specificity was 87%. The positive predictive value (PPV) was 93%, the negative predictive value (NPV) was 75%, and the accuracy was 86%.
Secondary endpoints included the sensitivity and specificity of 89Zr-DFO-girentuximab PET/CT in the subgroup of patients with IDRMs measuring 4 cm or less (cT1a). Among 179 evaluable patients, the sensitivity was 85.5%, and the specificity was 89.5%. The PPV was 93.4%, the NPV was 78%, and the accuracy was 87%.
Most adverse events were mild, but 18 patients had grade 3 or higher treatment-emergent adverse events. Most adverse events were thought to be related to nephrectomy, Dr Shuch noted.
Based on these results, Dr Shuch concluded that 89Zr-DFO-girentuximab PET/CT has the potential to improve care.
Disclosures: This research was supported by Telix Pharmaceuticals. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Shuch BM, Pantuck AJ, Bernhard J-C, et al. Results from phase 3 study of 89Zr-DFO-girentuximab for PET/CT imaging of clear cell renal cell carcinoma (ZIRCON). ASCO GU 2023. February 16-18, 2023. Abstract LBA602.
