Researchers are looking for better ways to diagnose kidney cancer. Currently, diagnosis is made using scans, which cannot tell the difference between benign and cancerous tumours, and biopsy, which involves surgery and is not always accurate. There is, therefore, an unmet need for an accurate test to diagnose kidney cancer to guide patient management.

Girentuximab is an antibody that attaches to an enzyme called carbonic anhydrase IX (CAIX). This enzyme is found in clear cell kidney cancer tumours.  89Zr-DFO-girentuximab (TLX250-CDx) is a product made from combining a weakly radioactive molecule called zirconium Zr 89 with girentuximab. When given to humans, 89Zr-DFO-girentuximab binds to carbonic anhydrase IX in kidney cancer tumours and can help to tell the difference between kidney cancer, normal tissue, and other tumours.

Patients who were scheduled to have a partial nephrectomy within 90 days were given 89Zr-DFO-girentuximab 10 days before surgery and then had a PET/CT scan 5 days later. The scans were assessed independently to determine whether the patient had kidney cancer. Both the sensitivity and accuracy of the scans where assessed.

There were 300 patients in the study, two thirds of whom had clear cell kidney cancer. The results were assessed independently by 3 radiographers. The average sensitivity was 86%, and the average accuracy was 87%. Positive predictive values for kidney cancer were more than 90%. There were only two treatment-related side effects.

This study confirms that 89Zr-DFO-girentuximab is well tolerated and can accurately identify kidney cancer from a PET/CT scan. This is promising for the management of kidney cancer patients.

Read more in the Journal of Clinical Oncology here