Purpose: Adjuvant pembrolizumab improved disease-free survival (DFS) and overall survival (OS) versus placebo in participants with renal cell carcinoma (RCC) at increased risk of recurrence after nephrectomy in the global phase 3 KEYNOTE-564 study. This post hoc subgroup analysis evaluated the efficacy and safety of adjuvant pembrolizumab in East Asian (Japan, South Korea, Taiwan) participants enrolled in KEYNOTE-564.
Materials and methods: Eligible participants were randomly assigned 1:1 to receive adjuvant pembrolizumab 200 mg or placebo intravenously every 3 weeks for ≤17 cycles. The primary endpoint was DFS by investigator assessment. OS was a key secondary endpoint. Safety was a secondary endpoint.
Results: The East Asian subgroup included 126 participants (pembrolizumab, n=58; placebo, n=68). Median follow-up was 62.1 months (range 49.6‒73.0). Hazard ratio for DFS with pembrolizumab versus placebo was 0.70 (95% confidence interval 0.41‒1.20). Median DFS was not reached with pembrolizumab versus 58.8 months with placebo; estimated 48-month rate was 61.3% versus 51.2%. Hazard ratio for OS was 0.47 (95% confidence interval 0.15‒1.49). Median OS was not reached with pembrolizumab and placebo; estimated 48-month rate was 94.8% versus 91.2%. Treatment-related adverse events occurred in 70.7% of participants (29.3% grade 3‒4) receiving pembrolizumab and 36.8% of participants (0.0% grade 3‒4) receiving placebo. No pembrolizumab-related deaths occurred.
Conclusion: In the KEYNOTE-564 East Asian subgroup, adjuvant pembrolizumab provided DFS and OS benefits versus placebo and had a safety profile consistent with the global results. These results further support pembrolizumab as adjuvant treatment for East Asian patients with RCC at increased risk of recurrence after nephrectomy.
Keywords: Asia; Immunoadjuvant; PD-1 inhibitor; Pembrolizumab; Renal cell carcinoma.