Sequential therapy is a standard strategy used to overcome the limitations of targeted agents in metastatic renal cell carcinoma. It remains unclear whether a mammalian target of rapamycin (mTOR) inhibitor is a more effective second-line therapy after first-line VEGF TKI has failed than the alternative, vascular endothelial growth factor tyrosine kinase inhibitor (VEGF TKI).Methods
A clinical database was used to identify all patients with mRCC treated with VEGF TKIs in the Asan Medical Center. Medical records were reviewed to identify those patients in whom first-line VEGF TKI failed and who were then treated with second-line VEGF TKI or mTOR inhibitors. Patient medical characteristics, radiological response and survival status were assessed.Results
Of the 83 patients who met the inclusion criteria, 41 received second-line VEGF TKI [sunitinib (n = 16) and sorafenib (n = 25)] and 42 were treated with mTOR inhibitors [temsirolimus (n = 11) and everolimus (n = 31)]. After a median follow-up duration of 23.9 months (95% CI: 17.8–30.0), progression-free survival was 3.0 months for both groups [hazard ratio (HR, VEGF TKI versus mTOR inhibitor) = 0.97, 95% CI: 0.59–1.62, P = 0.92]. Overall survival was 10.6 months for the VEGF TKI group and 8.2 months for the mTOR inhibitor group (HR = 0.98, 95% CI: 0.57–1.68, P = 0.94). The two groups did not differ significantly in terms of the disease control rate (51% for VEGF TKI and 59% for mTOR inhibitor, P = 0.75).Conclusions
Second-line VEGF TKI seems to be as effective as mTOR inhibitors and may be a viable option as a second-line agent after first-line anti-VEGF agents have failed.