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. In this study, the results of which will be presented at the virtual American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) in San Francisco at the weekend, cabozantinib has been shown to reduce the size of brain metastases without being toxic to the brain.
This was a retrospective study of 69 patients with brain metastases from RCC. For 25 of these patients, their cancer was progressive at the start of the study. When treated with cabozantinib there was a response rate of 61% for their brain metastases, including a complete response rate of 13%. The rate of brain disease progression at six months was 16% for these patients. For the remaining 44 patients, their cancer was not progressive, and they had a response rate of 57% for their brain metastases and 9% rate of brain disease progression at six months. Median overall survival was just over 14 months for both groups of patients.
“With these exciting results, oral systemic cabozantinib is showing intriguing activity on brain metastases in renal cell carcinoma,” said Dr Toni Choueiri, from the Dana-Farber Cancer Institute in the USA. “The high intracranial response rates seen in this retrospective analysis suggest cabozantinib has the potential for helping patients with difficult-to-treat brain lesions from kidney cancer. We look forward to building on these encouraging findings through the ongoing phase 2 CABRAMET trial led by our French colleagues, which is prospectively evaluating cabozantinib in patients with brain metastases from renal cell carcinoma.”