Brain metastases resulting from the spread of renal cell carcinoma (RCC) are especially difficult to treat because drugs are prevented from getting to the brain by a membrane called the blood-brain barrier. Also, patients with brain metastases from RCC are not allowed in most clinical trials, and there is an unmet need for treatment of these patients. Cabozantinib is effective in patients with metastatic RCC, but its effect on brain metastases remains unclear. In this study, cabozantinib has been shown to reduce the size of brain metastases without being toxic to the brain.
This was a retrospective study of 88 patients with brain metastases from RCC. For 33 of these patients, their cancer was progressive at the start of the study. When treated with cabozantinib there was a response rate of 55% for their brain metastases. The average time to when the treatment stopped working was 8.9 months and the overall survival time was 15 months. For the remaining 55 patients, their cancer was either stable or being treated with therapy directed at the brain. They had a response rate of 47% for their brain metastases. In this group of patients the average time to when the treatment stopped working was 9.7 months and overall survival time was 16 months.
In this study, cabozantinib was effective and safe for the treatment of brain metastases from RCC.