Efficacy and Safety of Selective Vascular Endothelial Growth Factor Receptor Inhibitors Compared with Sorafenib for Metastatic Renal Cell Carcinoma: a Meta-analysis of Randomised Controlled Trials

AIMS: Selective vascular endothelial growth factor receptor (VEGFR) inhibitors have the potential for greater potency and less off-target toxicity compared with multikinase tyrosine kinase inhibitors in the treatment of metastatic renal cell carcinoma. We carried out a meta-analysis to determine quantitatively the differences in comparative efficacy and tolerability between these newer, selective agents and the multikinase inhibitors. MATERIALS AND METHODS: We searched four electronic databases for published randomised controlled trials comparing selective VEGFR inhibitors with multikinase tyrosine kinase inhibitors for metastatic renal cell carcinoma and carried out a meta-analysis. Outcomes of interest were progression-free survival, objective response rate (ORR), overall survival, discontinuation of treatment due to adverse events (DAE) and occurrence of specific toxicities. RESULTS: Four trials involving the selective VEGFR inhibitors axitinib, tivozanib and dovitinib were analysed, all using sorafenib as the comparator. There was a 22% reduction in risk of disease progression with selective VEGFR inhibitors (relative risk 0.78; 95% confidence interval 0.69-0.87) compared with sorafenib, the tyrosine kinase inhibitor in all trials, and similar whether the agents were first-line or subsequent therapy. ORR was improved with selective VEGFR inhibitors, with 91% increased odds over sorafenib (odds ratio 1.91; 95% confidence interval 1.35-2.69). Overall survival was similar between groups (relative risk 1.03; 95% confidence interval 0.88-1.21) and DAE differed only in sensitivity analysis with exclusion of dovitinib (odds ratio 0.62; 95% confidence interval 0.41-0.94). Frequencies of the most common toxicities were overall similar, but differences included more frequent grade 3 or 4 fatigue and less frequent palmar-plantar erythrodysesthesia with selective VEGFR therapy. CONCLUSION: Although selective VEGFR inhibitors are associated with similar overall survival as multikinase inhibitor sorafenib, they show significant improvement in progression-free survival, regardless of first-line or later use, and ORR compared with sorafenib. Tolerability due to toxicities is similar