Clinical Decisions in Patients With RCC Bone Metastases

Toni Choueiri, MD:In addition, the study looked at several questions, some subgroup analyses. One of the interesting things that panned out with cabozantinib, which was somewhat known from the trial that used cabozantinib in prostate cancer, was that predominately when it metastasized close to the bones, a renal cell cancer also can go to the bones but to a lesser extent.

But a subgroup analysis looked specifically at bone metastases versus everolimus and compared them with the patient who did not have bone metastases, knowing that the incidence on METEOR of bone metastases is between 20% and 30%. So, those patients seemed to benefit more.

If you look at the hazard ratio for both progression-free survival and overall survival compared with everolimus, patients with bone metastases do much better if they’re treated with cabozantinib compared with if they’re treated with everolimus. I think this is important because patients with bone metastases usually do not do very well, as the responses to traditional VEGF tyrosine kinase inhibitors, such as sunitinib and pazopanib, are not that great.

The study also looked at response rate, and the bone scan rate seems to be higher with cabozantinib. The study also looked to see if there is any other endpoint that justifies cabozantinib and bone metastases. What’s cabozantinib doing in the microenvironment? And actually, the bone biomarkers seem to be modulated to a greater extent with cabozantinib. So, there’s an emerging story here with cabozantinib and bone metastases, and I think it could be an agent of choice in those patients with extensive bony disease that can differentiate itself from other tyrosine kinase inhibitors.

Transcript edited for clarity.