Efficacy of second-line ICIs combined with TKIs among patients with metastatic renal cell carcinoma: a real-world study

Aim: To evaluate the efficacy of immune checkpoint inhibitors (ICIs) plus tyrosine kinase inhibitors (TKIs) as second-line treatment in patients with metastatic renal cell carcinoma (mRCC). Patients & methods: Baseline and follow-up data from patients with mRCC treated with second-line ICIs plus TKIs or TKIs alone from a single institution were retrospectively gathered. Results: A total of 110 patients were included. The objective response rate was higher among patients treated with ICIs plus TKIs than those treated with TKIs alone (36.5 vs 12.1%; p = 0.002). Treatment with ICIs plus TKIs was associated with longer progression-free survival (15.0 vs 9.0 months; p = 0.009) and overall survival (not reached vs 16.0 months; p = 0.018) than TKI monotherapy. The survival rates at 2 (83.0 vs 74.4%; p = 0.426) and 3 years (58.1 vs 47.5%; p = 0.214) between the two groups were not statistically different. Notably, patients with certain clinicopathological features tended to gain more survival benefits with combined therapy. Conclusion: ICIs plus TKIs showed superior progression-free survival time and tumor response rate over TKIs alone as second-line treatment in patients with mRCC. Future randomized prospective trials are necessary to validate these preliminary findings. Plain language summary Aim: To evaluate the efficacy of immune checkpoint inhibitors (ICIs) combined with tyrosine kinase inhibitors (TKIs) in patients with previously treated metastatic renal cell carcinoma (mRCC). Patients & methods: Data at initial treatment and follow-up of patients with mRCC with second-line ICIs plus TKIs or TKIs alone were documented. Results: A total of 110 patients were included. The tumor shrinkage rate was higher among patients treated with ICIs plus TKIs than those treated with TKIs alone. Patients receiving ICIs plus TKIs had delayed disease progression and longer survival time compared with patients treated with TKI monotherapy. However, patients had a similar probability of survival after 2 and 3 years of treatment. Notably, patients with certain clinicopathological characteristics gained more survival benefits from ICIs plus TKIs. Conclusion: ICIs plus TKIs showed superior efficacy over TKIs alone in previously treated patients with mRCC. Future randomized prospective trials are necessary to validate these preliminary findings.