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

Abstract 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). These findings suggest that maintaining an RDI ≥ 80% in IO-TKI therapy may accelerate treatment discontinuation due to AEs and negatively affect the prognosis.. Careful dose adjustment of TKIs may be necessary to optimize outcomes in Japanese patients with RCC receiving IO-TKI combination therapy.