Efficacy of subsequent immunotherapy-tyrosine kinase inhibitor combinations after TKI monotherapy failure in patients with intermediate/poor risk metastatic clear cell renal cell carcinoma: A real-world retrospective study

e16537 Background: The randomized phase 3 trials KEYNOTE-426, CheckMate 9ER, and CLEAR have demonstrated the efficiency of immunotherapy-based drug combinations as first-line treatment for metastatic clear cell renal cell carcinoma (mccRCC). Immunotherapy-tyrosine kinase inhibitor (IO-TKI) has shown significant benefits over sunitinib monotherapy with respect to overall survival in mccRCC patients with intermediate/poor international metastatic database consortium (IMDC risk group). However, most of the patients received second-line TKI or immune checkpoint inhibitors therapy after TKI monotherapy failure in those clinical trials. The role of IO-TKI after disease progression in sunitinib monotherapy cohort was not fully investigated. We sought to evaluate the efficacy of second-line IO-TKI for mccRCC patients with IMDC intermediate/poor risk who had previously received at least one line of TKI monotherapy. Methods: We conducted retrospective analysis of IMDC intermediate/poor risk mccRCC patients treated with IO-TKI during any treatment line at our center from June 2019 to April 2022. Demographic, clinicopathological, and systemic therapy data were collected. The primary end point was overall survival (OS), defined as the time from initiation of treatment to death from any cause or last follow-up. The secondary end point was progression-free survival (PFS), defined as the time to the first documented disease progression. Results: Overall, 81 IMDC intermediate/poor risk mccRCC patients were enrolled, with a median follow-up of 17 months. 49 patients received first-line IO-TKI therapy, 32 patients who had previously received at least one line of TKI monotherapy received second-line IO-TKI after disease progression. The objective response rate (ORR) and median PFS of second-line IO-TKI after TKI monotherapy failure was 28.6% and 9 months, respectively. OS between first-line IO-TKI therapy and second-line IO-TKI after TKI monotherapy failure was not statistic significant (30 months vs. 26 months, p = 0.630). Conclusions: In this real-world retrospective study, we observed antitumor activity of second-line IO-TKI for mccRCC patients with IMDC intermediate/poor risk after disease progression. Notably, first-line IO-TKI therapy did not have superior OS when TKI monotherapy patients received second-line IO-TKI therapy. Randomized trials are needed to evaluate optimal combination strategies and sequencing of therapies in mccRCC.