# CAIX imaging of the indeterminate renal mass

Source: https://nuclide.cc/opportunities/opp-caix-indeterminate-renal-mass/  
Nuclide record `opp-caix-indeterminate-renal-mass` (Opportunity). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Scans find small kidney lumps all the time and cannot tell which are cancer. Up to one in five that are surgically removed turn out to be harmless. A scan that recognises the commonest kidney cancer would spare those operations, and it needs no drug to be useful.

## Summary

This is the cleanest standalone diagnostic case in the field: the scan answers a question on its own, with no therapy dependency. Between 12.8% and 40% of surgically resected small renal masses are benign depending on size, and no imaging technique reliably defines histological subtype before surgery.

The lead agent has the evidence. 89Zr-girentuximab (TLX250-CDx, Zircaix) reported phase 3 ZIRCON results in Lancet Oncology in October 2024: 300 patients dosed, 284 evaluable, sensitivity 85.5% and specificity 87.0% for clear cell renal cell carcinoma, with no safety signals. The BLA was accepted with priority review and a PDUFA date of 27 August 2025, but the FDA issued a complete response letter on chemistry, manufacturing and controls rather than efficacy or safety; the sponsor has since reported agreement on remediation after Type A meetings. It remains unapproved anywhere.

Behind it sit peptide and small-molecule CAIX ligands with same-day kinetics: 68Ga-DPI-4452 has FDA Fast Track designation and first-in-human data, and a technetium-99m CAIX peptide and a gallium-68 CAIX agent have small first-in-human cohorts. Chinese academic work includes a 47-patient 68Ga-NY104 cohort. The opportunity split is therefore sharp: the antibody owns the evidence and the regulatory queue, while the unmet need for a same-day, widely distributable agent is unmet by definition because no peptide has a phase 3.

## Fields

- Kind: Opportunity
- Last checked: 2026-09-23
- Also known as: CA9 imaging; girentuximab PET
- Tags: standalone diagnostic; kidney; biopsy avoidance

## Sources

- ZIRCON phase 3, Lancet Oncology 2024: https://pubmed.ncbi.nlm.nih.gov/39270701/
- NCT03849118: ZIRCON: https://clinicaltrials.gov/study/NCT03849118
- Girentuximab dosimetry: https://pmc.ncbi.nlm.nih.gov/articles/PMC8426244/
- Benign proportion of resected small renal masses: https://pmc.ncbi.nlm.nih.gov/articles/PMC2797464/

## Connected records

- isotopes: [Gallium-68](https://nuclide.cc/isotopes/ga-68/), [Technetium-99m](https://nuclide.cc/isotopes/tc-99m/), [Zirconium-89](https://nuclide.cc/isotopes/zr-89/)
- indications: [Renal cell carcinoma](https://nuclide.cc/indications/rcc/)
- technologies: [CAIX PET (89Zr-girentuximab)](https://nuclide.cc/technologies/caix-pet/), [Immuno-PET](https://nuclide.cc/technologies/immuno-pet/), [PET/CT](https://nuclide.cc/technologies/pet-ct/)
- targets: [CAIX (carbonic anhydrase IX)](https://nuclide.cc/targets/caix/)
- drugs: [177Lu-edotreotide](https://nuclide.cc/drugs/itm-11/), [Zirconium-89 girentuximab](https://nuclide.cc/drugs/girentuximab-zr89/)

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