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.