An Investigational Scan (89Zr-DFO-GmAb PET/CT) Compared to Contrast-Enhanced CT for the Detection of Recurrent Clear Cell Renal Cell Cancer After Surgery Comparing Carbonic Anhydrase IX (CAIX) PET CT to Conventional PET CT for Post-Op Staging in Kidney Cancer

This phase II trial compares the safety and effectiveness of 89Zr-DFO-GmAb positron emission tomography (PET)/computed tomography (CT) compared to contrast-enhanced CT after surgery in detecting clear cell renal cell cancer that has come back (recurrent). For some patients, the risk of recurrence after surgery remains high. Conventional CT methods, such as contrast-enhanced CT, may not detect small volume or micrometastatic disease. PET/CT with radiotracers, such as 89Zr-DFO-GmAb, may improve detection of tumor cells. Girentuximab (GmAb), a monoclonal antibody, is tagged with zirconium-89, a radioactive atom (which is also known as an isotope). The zirconium-89 (89Zr) isotope is attached to girentuximab with desferrioxamine (DFO) and this combined product is called 89Zr-DFO-girentuximab. 89Zr-DFO-girentuximab attaches itself to a protein on the surface of clear cell renal cell tumor cells called CAIX. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this research, 89Zr-DFO-GmAb. Because some cancers, including clear cell renal cell cancer, take up 89Zr-DFO-GmAb it can be seen with PET. CT utilizes x-rays that traverse body from the outside. CT images provide an exact outline of organs and potential inflammatory tissue where it occurs in patient's body. Using contrast agents with CT scan to enhance the images (contrast-enhanced CT) is standard of care imaging. 89Zr-DFO-GmAb PET/CT may be safe and effective compared to contrast-enhanced CT in detecting recurrent clear cell renal cell cancer after surgery.

PRIMARY OBJECTIVE:

1. To compare the lesion detection rate (i.e., positivity rate per patient) of zirconium Zr 89 girentuximab (89Zr-DFO-GmAb) PET/CT compared to the standard of care diagnostic contrast-enhanced CT alone at 4-12 weeks from surgical resection based on blinded independent central review (BICR).

SECONDARY OBJECTIVES:

1. To establish safety of 89Zr-DFO-GmAb in patients with intermediate-high or high risk imaged in the post-nephrectomy or metastasectomy setting.

II. To compare the positive predictive value (PPV) of 89Zr-DFO-GmAb PET/CT in patients with available lesion validation by 1) histopathology (biopsy/resection), 2) evidence of growth under surveillance or 3) reduction of size under treatment, and 4) unequivocal confirmation of malignancy on a different imaging modality.

III. To assess the recurrence-free survival of individuals with/without evidence of disease based on 89Zr-DFO-GmAb PET/CT staging results (PET/CT designated M1 versus [vs] M0).

EXPLORATORY OBJECTIVES:

1. Correlate level of histological CAIX expression (H Score) from the primary tumor to 89Zr-TLX250 standardized uptake values (SUVs) in patients with visualized disease on 89Zr-DFO-GmAb PET/CT.

II. To identify the standardized uptake value (SUV) cut-off for 89Zr-DFO-GmAb suitable for the detection of metastatic lesions in the postoperative setting.

III. To evaluate the performance of established prognostic transcriptomic classifiers (from the nephrectomy specimen) on disease-free survival.

IV. To evaluate if circulating tumor DNA (ctDNA) for the detection of molecular residual disease (MRD) correlates with the presence of active disease seen on 89Zr-DFO-GmAb PET/CT or predicts disease-free survival.

OUTLINE:

Patients receive 89Zr-DFO-GmAb intravenously (IV) over 3 minutes on day 0 then undergo whole body PET/CT and standard of care (SOC) diagnostic contrast-enhanced CT scan on day 7. Patients also blood sample collection on study. In addition, patients may undergo bone scan and CT or magnetic resonance imaging (MRI) of the brain on study as clinically indicated.

After completion of study intervention, patients are followed up at 8, 16 and 24 months.