Effectiveness and Safety of Second-line Tyrosine Kinase Inhibitors After Discontinuation of First-line Immune-oncology Combination Therapy Because of Adverse Events in the Patients With Metastatic Renal Cell Carcinoma

Introduction: Effectiveness and safety of second-line tyrosine kinase inhibitors (TKIs) in patients with metastatic renal cell carcinoma (mRCC) for whom first-line immuno-oncology (I-O) combination therapy was discontinued because of adverse events (AEs) remain to be determined. Patients and methods: Clinicopathological data were retrospectively collected from 34 institutions between August 2018 and January 2022 for 243 patients with mRCC who received second-line TKIs after first-line I-O combination therapy. Two patients who requested discontinuation of first-line I-O combination therapy were excluded. Oncological outcomes and safety were compared between patients who discontinued first-line I-O combination therapy because of progressive disease (Group PD) and AEs (Group AE). First- and second-line overall survival (OS) were defined as the time from the start of first- and second-line therapy to death, respectively. Propensity score matching was applied to adjust prognostic factors between the 2 groups. Results: There were 179 patients in Group PD and 62 patients in Group AE. Objective response rate and disease control rate were similar between the 2 groups. Progression-free survival (PFS), second-line OS, and first-line OS were significantly longer in Group AE than in Group PD (median 13.6 months vs. 8.5 months, P = 0.005; median not reached [NR] vs. 19.5 months, P =.005; median NR vs. 30.8 months, P =.012, respectively). After propensity score matching, PFS and second-line OS were still significantly longer and first-line OS tended to be longer in Group AE than in Group PD. There were no significant differences in the occurrence of AEs of any grade, including severe grades of 3 or greater, between the 2 groups. Conclusion: Second-line TKIs are safe and at least as effective in patients with mRCC who discontinued first-line I-O combination therapy because of AEs as they are in patients who discontinued because of PD.