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

Introduction: 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.

Methods: 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.

Results: 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.

Conclusion: 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.