Salvage lenvatinib/everolimus (LE) combination therapy after immune checkpoint inhibitor (ICI) and VEGFR tyrosine kinase inhibitor (TKI) for metastatic renal cell carcinoma (mRCC).

Abstract

e16520 Background: The optimal treatment for mRCC patients (pts) who have progressed after both ICI and TKI remains uncertain. LE is frequently used as a salvage treatment due to different antitumor mechanisms, but efficacy and toxicity data in this setting are limited. Methods: We retrospectively reviewed charts from two academic centers for 71 adult mRCC pts who received LE after prior ICI and TKI exposure. Collected data included patient demographics, histology, International mRCC Database Consortium (IMDC) risk group, treatment history, and toxicity details using CTCAEv5. Outcomes were objective response rate (ORR) per RECIST 1.1, median time to treatment failure (mTTF), and toxicity. Descriptive statistics, Cox proportional hazards model and Kaplan-Meier method were utilized. Results: The median age was 64 (range: 31–84). Most pts had clear cell histology (84.5%) and had undergone nephrectomy (75%). IMDC risks were favorable (19.7%), intermediate (int) (66.2%), poor (11.3%), and unknown (2.8%). Pts received a median of 3 (range 1-10) prior therapy lines (L) and 42 pts had sequential ICI and TKI, while 29 received ICI/TKI combination therapy. Average ORR was 26.8%, but numerically better when given earlier (2L/3L vs. ≥4L: 28.6% vs. 22%). The mTTF was 5.5 months (m) (95% confidence interval [CI], 3.5–7.6 m), which was not significantly changed by sequential or combinational ICI/TKI treatment exposure. In multivariable Cox analyses, int/poor IMDC risk was associated with a significantly worse TTF compared to favorable risk (HR, 2.2, 95% CI, 1.1-4.1; mTTF: 4.5 vs 12.9 m), and so was ≥4L treatment compared to 2L/3L treatment (HR, 3.2, 95% CI, 1.3-7.6; mTTF: 4.5 vs. 6.6 m). In 57 pts with int/poor IMDC risk, ≥4L treatment was associated with a significantly worse TTF (HR, 2.3, 95% CI, 1.2-4.5; mTTF: 3.6 vs. 6.6 m), while prior nephrectomy was associated with a significantly better TTF (HR, 0.46, 95% CI, 0.22-0.97; mTTF: 5.4 vs. 3.1 m) compared to those without nephrectomy. Of the 71 pts, 64% had ≥ grade 3 adverse events, 60% had treatment interruption, 44.3% had dose reduction, and 21% stopped treatment due to intolerance. Conclusions: LE therapy is feasible but has modest efficacy following ICI/TKI treatment. Pts with favorable risk, prior nephrectomy or early salvage may have a better treatment response. These observations need to be confirmed in prospective studies.