Supplementary Material for: Pembrolizumab as Second-Line Therapy for Advanced Hepatocellular Carcinoma: A Subgroup Analysis of Asian Patients in the Phase 3 KEYNOTE-240 Trial

<b><i>Introduction:</i></b> KEYNOTE-240 investigated the efficacy and safety of pembrolizumab plus best supportive care (BSC) in sorafenib-treated patients with advanced hepatocellular carcinoma (HCC). Results for the subgroup of patients from Asia are described. <b><i>Methods:</i></b> Adults with advanced HCC previously treated with sorafenib were randomized 2:1 to pembrolizumab or placebo plus BSC. Here, the Asian subgroup comprised patients enrolled in Hong Kong, Japan, Korea, the Philippines, Taiwan, and Thailand. Primary endpoints were progression-free survival (PFS) per blinded central imaging review and overall survival (OS). Secondary endpoints included objective response rate (ORR) per blinded central imaging review, duration of response (DOR), and safety. <b><i>Results:</i></b> The Asian subgroup included 157 patients. As of January 2, 2019, the median follow-up in this subgroup was 13.8 months for pembrolizumab and 8.3 months for placebo. The median PFS was 2.8 months for pembrolizumab (95% confidence interval [CI] 2.6–4.1) versus 1.4 months (95% CI 1.4–2.4) for placebo (hazard ratio [HR] 0.48; 95% CI 0.32–0.70). The median OS was 13.8 months (95% CI 10.1–16.9) for pembrolizumab versus 8.3 months (95% CI 6.3–11.8) for placebo (HR 0.55; 95% CI 0.37–0.80). ORR was 20.6% (95% CI 13.4–29.5) for pembrolizumab versus 2.0% (95% CI 0.1–10.6) for placebo (difference: 18.5%; 95% CI 8.3–27.6). The median DOR was 8.6 and 2.8 months for pembrolizumab and placebo, respectively. Any grade treatment-related adverse events (TRAEs) occurred in 63 patients (58.9%) receiving pembrolizumab and 24 patients (48.0%) receiving placebo; 14 (13.1%) and 2 (4.0%) patients experienced grade 3–5 TRAEs, respectively. No treatment-related deaths occurred. <b><i>Conclusion:</i></b> Pembrolizumab demonstrated antitumor activity and was well tolerated in the Asian subgroup of KEYNOTE-240. A trend toward greater benefit with pembrolizumab in the Asian subgroup was observed compared with the overall cohort, supporting further evaluation of pembrolizumab treatment in this population.