The efficacy of second-line tyrosine kinase inhibitor for patients with metastatic non-clear cell renal cell carcinoma following first-line immune-oncology combination therapy.

Purpose: Metastatic non-clear cell renal cell carcinoma (nccRCC) is a heterogeneous disease with a poor prognosis and is treated with immunotherapy (IO)-based combinations according to the clear cell renal cell carcinoma. Tyrosine-kinase inhibitors (TKIs), such as cabozantinib and axitinib, are commonly used as the 2nd line therapy after 1st line IO combination therapy, but their efficacy as 2nd line TKI therapy for nccRCC is unknown. In this study, we performed a retrospective multicenter analysis of nccRCC patients who were previously treated with IO combination therapy and received 2nd line TKIs.

Methods: Among 254 patients enrolled in the Japanese multicenter retrospective study, 52 patients with nccRCC histology who received second-line TKIs were included in this study. Progression-free survival and overall survival (OS) from 2nd line TKIs were analyzed by log-rank test and Cox-proportional hazard model. Objective response rate (ORR) of 2nd line TKIs were analyzed.

Results: The 1-year PFS and OS rates were 25.0% (95% CI = 13.1-36.8) and 63.8% (95% CI, 48.0-75.9), respectively. No patients had a complete response, 11 had a partial response, and 18 had stable disease. ORR was 21.1%. IMDC poor risk and sunitinib as the 2nd line therapy were significantly associated with poor PFS.

Conclusion: The 2nd-line TKI was effective for a small group of nccRCC patients previously treated with IO combination therapy, although this study was retrospectively analyzed with a small number of cases.