Comparative efficacy of immune checkpoint inhibitor combination therapies by metastatic site in metastatic renal cell carcinoma

Few studies have investigated the efficacy of immuno-oncology (IO) combinations at different metastatic sites in renal cell carcinoma (RCC). We evaluated the differential efficacy of IO–IO and IO–tyrosine kinase inhibitor (TKI) combinations by metastatic site in metastatic RCC (mRCC). This retrospective multicenter study by the JK-FOOT Study Group included 579 patients with intermediate- or poor-risk mRCC (per International Metastatic RCC Database Consortium criteria) treated with first-line IO combinations between September 2018 and December 2024. Metastatic sites were lymph nodes, lungs, bones, liver, brain, and others. The primary endpoints were progression-free survival (PFS) and overall survival (OS); the secondary endpoint was objective response rate. Efficacy was compared between IO–IO and IO–TKI for each site. For lymph node (n = 36), lung (n = 132), or brain (n = 16) metastases, OS or PFS was not significantly different between IO–IO and IO–TKI. In bone metastases (n = 80), OS tended to favor IO–TKI (P = 0.053). In liver metastases (n = 22), OS was significantly longer with IO–TKI (P = 0.011). IO–TKI may be a more appropriate first-line option than IO–IO for mRCC with bone or liver metastases, while efficacy is similar for other sites.