Impact of high relative dose intensity on effectiveness and treatment continuity of IO-TKI therapy in Japanese advanced renal cell carcinoma

This study investigated the impact of relative dose intensity (RDI) on the effectiveness and safety of immuno-oncology plus tyrosine kinase inhibitor (IO-TKI) therapy in Japanese patients with renal cell carcinoma (RCC). A total of 145 patients receiving first-line treatment were analyzed: 55 received IO-TKI therapy and 90 received immuno-oncology combination (IO-IO) therapy. Patients in the IO-TKI group were divided based on an RDI threshold of 80% into high- and low-RDI groups. Median progression-free survival (mPFS) was significantly longer in the IO-TKI group compared to the IO-IO group (P < 0.05), while no significant difference in median overall survival (mOS) was observed (P = 0.53). Interestingly, the mOS tended to be shorter in the IO-TKI high-RDI group than in the IO-TKI low-RDI (P = 0.05) and IO-IO groups (P = 0.13). Moreover, treatment discontinuation due to adverse effects occurred earlier in the IO-TKI high-RDI group (P < 0.05). An association was found between RDI ≥ 80% in IO-TKI therapy, discontinuation due to adverse events, and poor prognosis. Careful dose adjustment of TKIs may be necessary to optimize outcomes in Japanese patients with RCC receiving IO-TKI combination therapy.