Here’s a groundbreaking revelation: Kidney cancer patients with brain metastases, often left with limited treatment options, may finally have a reason to hope. A recent study has unveiled promising results for cabozantinib (Cabometyx) in this challenging patient population, shedding light on its potential to extend progression-free survival (PFS) and improve response rates. But here's where it gets even more intriguing—the drug’s efficacy appears particularly pronounced in specific subgroups, sparking conversations about personalized treatment strategies.
At the International Kidney Cancer Symposium (IKCS) in Denver, Sylvie Negrier, MD, PhD, of the Claude Berard Center and University of Lyon, presented findings from a small but impactful prospective study. Among 25 evaluable patients with non-locally treated brain metastases from kidney cancer, 56% remained free of metastatic progression at the 6-month mark, with an overall response rate of 61%. Even more striking, the median duration of brain metastasis response had yet to be reached, suggesting sustained benefits. Extracranial responses mirrored this success, with 40% of patients achieving partial responses and 52% experiencing stable disease. The median PFS stood at 8.1 months, while brain metastasis-specific PFS reached 10.7 months, all without new safety concerns.
But here’s where it gets controversial: Negrier highlighted that cabozantinib’s efficacy was most notable in first-line patients or those without prior tyrosine kinase inhibitor (TKI) treatment. This raises the question: Are we underutilizing cabozantinib by not prioritizing it earlier in the treatment sequence? And this is the part most people miss—patients with brain metastases from kidney cancer have historically been excluded from clinical trials, leaving them with limited therapeutic options. Could this study mark a turning point in their care?
Adding another layer to the discussion, a retrospective study presented at IKCS showcased a 71% response rate when cabozantinib was paired with nivolumab (Opdivo) in patients with fumarate hydratase-deficient renal cell carcinoma (FH-dRCC). Maria Carlo, MD, of Memorial Sloan Kettering Cancer Center, emphasized that this combination extends beyond non-clear cell RCC, where it’s already a preferred treatment. FH-dRCC, a rare subtype linked to hereditary leiomyomatosis and RCC syndrome, has long lacked effective therapies. While combinations like erlotinib and bevacizumab have shown some efficacy, recurrence remains a challenge. Emerging data on immune checkpoint inhibitors paired with TKIs, such as sintilimab plus axitinib and tislelizumab plus lenvatinib, have demonstrated impressive response rates, but the optimal regimen is still up for debate.
In Carlo’s study, 14 FH-dRCC patients treated with cabozantinib and nivolumab achieved a 71% objective response rate and an 85.7% disease control rate, with a median PFS of 15.1 months and OS of 37.3 months. Could this combination become the new standard for FH-dRCC? Or is there room for further refinement in sequencing and dosing?
The CABRAMET trial, a phase II multicenter study, enrolled 26 adults with metastatic RCC and non-locally treated brain metastases, treating them with open-label cabozantinib. With a median age of 67 and a predominantly male cohort, the study confirmed the prespecified 6-month brain metastasis PFS endpoint. Notably, 86% of treatment-naïve patients responded, compared to 67% with prior immunotherapy and 40% with prior TKI exposure. Tumor shrinkage was observed in 21 patients, and median overall survival reached 15 months.
Here’s the burning question: With these compelling results, should cabozantinib—alone or in combination—be reconsidered as a first-line option for select kidney cancer patients? Or are we jumping the gun, awaiting larger trials to validate these findings? Share your thoughts in the comments—let’s spark a debate that could shape the future of kidney cancer treatment.
