Outcomes With Combination Pembrolizumab and Axitinib in Second and Further Line Treatment of Metastatic Renal Cell Carcinoma

Combination immune checkpoint inhibitors (ICI) and vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGF-R-TKI), including pembrolizumab/axitinib, are approved for first-line treatment of metastatic renal cell carcinoma (mRCC). Pembrolizumab/axitinib is associated with superior progression free survival (PFS), objective response rate (ORR), and overall survival over sunitinib. However, to date, the activity and safety of pembrolizumab/axitinib in later lines of therapy has not been reported.Clinical data of consecutive patients receiving pembrolizumab/axitinib in the second-line or beyond for mRCC at Yale-New Haven Hospital were retrospectively collected. Best objective response was assessed using RECIST 1.1 criteria. Kaplan-Meier function was used to analyze survival.Thirty-eight patients were included. Median age was 64, 92.1% had clear cell mRCC, 18.4% had sarcomatoid dedifferentiation; 94.7% had prior ICI and 39.5% had prior VEGF-R-TKI. Pembrolizumab/axitinib was administered as second-line therapy in 21 (55.5%) patients, third-line in 5 (13.2%) and beyond in 12 (30.2%). Adverse events (AEs) occurred in 86.8% of patients. Grade 3-4 AEs attributed to pembrolizumab and axitinib were seen in 18.4% and 6.4% of patients, respectively. No grade 5 AEs occurred. At a median follow up of 17.1 months, median PFS was 9.7 months (95% CI, 4.1-15.3). Amongst 36 response evaluable patients, the ORR was 25.0% (all partial) and disease control rate (including stable disease for at least 6 months) was 66.6%. The most frequent treatment sequence was first-line nivolumab/ipilimumab followed by second-line pembrolizumab/axitinib (n = 17, 44.7%); among this cohort, median PFS with pembrolizumab/axitinib was 11.1 (95% CI, 8.4-13.7) months, with an ORR of 31.4%.Combination pembrolizumab/axitinib among previously treated mRCC patients has activity, with AE rates comparable to those reported in the first line. Prospective studies evaluating ICI-VEGF-R-TKI combinations beyond first-line are warranted to identify the most beneficial treatment sequencing in mRCC.