Cabozantinib in the treatment of metastatic renal cell carcinoma - final data analysis from four oncology centers in the Czech Republic.

Abstract

Current standard treatments for patients with metastatic renal cell carcinoma (mRCC) involve tyrosine kinase inhibitors (TKI) that inhibit angiogenesis. Cabozantinib is a multi TKI used for the treatment of mRCC in the first- and second-line setting. The aim of this study was the final analysis of treatment outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with cabozantinib after previous targeted therapy. A total of 54 patients with mRCC from four oncology centers in the Czech Republic were evaluated retrospectively; the median follow-up was 18.5 months. Cabozantinib was administered in a dose of 60mg/day, a subset of patients received an initial dose of 40mg/day. The treatment was administered until the progression. The Kaplan-Meier analysis was used to calculate progression free survival (PFS) and overall survival (OS). We performed a multivariate analysis of risk factors for treatment outcomes (PFS, OS) by regression analysis. All statistics were evaluated at the significance level α = 0.05. The median PFS in all patients was 9.3 months (95% CI 7.2 - 11.4). The median OS in all patients was 21.9 months (95% CI 15.5 - 28.4). The median PFS in patients with bone metastases was not statistically significantly different compared with patients without bone metastases (9.3 vs 8.7 months, P = 0.53). The median OS in patients with bone metastases was statistically significantly shorter compared with patients without bone metastases (17.7 vs 26.8 months, P = 0.021). A treatment response was observed in 40.7 % of cases, including one complete remission. The regression analysis demonstrated a significant effect on OS in patients with the presence of subsequent treatment (P = 0.001), patients with treatment duration of first line therapy 6 months (P = 0.019) and 12 months (P = 0.003) and in patients without bone metastases (P = 0.021). Our final analysis of patients with mRCC treated with cabozantinib after previous targeted therapy confirmed its effectiveness.