Comparison of the Use of Immune Checkpoint Inhibitor/Tyrosine Kinase Inhibitor and Tyrosine Kinase Inhibitor Alone for Patients With Low Risk Metastatic Renal Cell Carcinoma

Currently, a combination of an immune checkpoint inhibitor (ICI) and a tyrosine kinase inhibitor (TKI) is the most widely used first-line treatment for metastatic renal cell carcinoma (mRCC). However, patients in the IMDC favourable risk group have been reported to have a relatively good prognosis, even when they undergo TKI monotherapy. The aim of this study was to evaluate whether ICI/TKI combination therapy or TKI monotherapy is more effective in patients with favourable IMDC risk.

We retrospectively reviewed 11 patients with favourable IMDC risk who underwent ICI/TKI combination therapy and 12 who underwent TKI monotherapy as first-line treatment for mRCC at our institution between April 2008 and September 2024 and compared their characteristics and treatment outcomes. The endpoints were overall survival (OS), progression-free survival (PFS) and treatment response, which was assessed using the overall response rate (ORR) and disease control rate (DCR). The safety of the regimens was evaluated using the incidences of grade ≥3 adverse events (AEs) and treatment discontinuation.

There was a significant difference between the groups regarding the duration of follow-up (24.4 months for the ICI/TKI group vs. 65.9 months for the TKI group, p=0.01), but no other differences were noted in the characteristics of the patients. The PFS and OS of the groups did not significantly differ following initial treatment. The ORR did not significantly differ, but tended to be better in the ICI/TKI group. The incidence of grade ≥3 AEs and the discontinuation of treatment owing to AEs did not significantly differ but tended to be higher in the TKI group.

Based on its superiority with respect to ORR and AE at our Institution, ICI/TKI therapy should be considered whenever possible, even in patients in the IMDC favourable risk group.