Cabozantinib in Pretreated Patients with Metastatic Renal Cell Carcinoma with Sarcomatoid Differentiation: A Real-World Study

Background Renal cell carcinoma with sarcomatoid differentiation is a highly aggressive form of kidney cancer. Objective We aimed to analyze the outcomes of patients treated with cabozantinib for metastatic renal cell carcinoma with sarcomatoid features. Methods We retrospectively collected data from 16 worldwide centers. Overall survival and progression-free survival were analyzed using Kaplan-Meier curves. Cox proportional models were used for univariate and multivariate analyses. Results We collected data from 66 patients with metastatic sarcomatoid renal cell carcinoma receiving cabozantinib as second-line (51%) or third-line (49%) therapy. The median progression-free survival from the start of cabozantinib was 7.59 months (95% confidence interval [CI] 5.75-17.49) and was longer in male patients (8.81 vs 5.95 months, p = 0.042) and in patients without bone metastases (7.59 vs 5.11 months, p = 0.010); the median overall survival was 9.11 months (95% CI 7.13-23.80). At the multivariate analysis, female sex (hazard ratio = 1.81; 95% CI 1.02-3.37, p = 0.046), bone metastases (hazard ratio = 2.62; 95% CI 1.34-5.10, p = 0.005), and International Metastatic Renal Cell Carcinoma Database Consortium criteria (hazard ratio = 3.04; 95% CI 1.54-5.99, p = 0.001) were significant predictors of worse overall survival. Conclusions Our data show that cabozantinib is active in pretreated patients with sarcomatoid renal cell carcinoma. Biomarkers are needed in this field to select patients for multi-kinase inhibitors or other options.