S-1 versus placebo in patients with sorafenib-refractory advanced hepatocellular carcinoma (S-CUBE): a randomised, double-blind, multicentre, phase 3 trial

Background Unresectable advanced hepatocellular carcinoma is a heterogeneous disease, for which sorafenib is the first targeted agent approved for first-line therapy, and treatment options for patients with sorafenib-refractory advanced hepatocellular carcinoma are limited. We assessed the efficacy and safety of S-1, a chemotherapeutic agent based on fluorouracil, in patients with sorafenib-refractory advanced hepatocellular carcinoma. Methods We did a randomised, double-blind, placebo-controlled, phase 3 study done at 57 sites in Japan. Patients with advanced hepatocellular carcinoma who were ineligible for surgical or local-regional therapy and judged refractory to sorafenib (ie, had progressed on sorafenib or had discontinued sorafenib because of adverse events) were randomly assigned (2:1) to receive oral S-1 (weight-banded 80 mg/m(2) [80-120 mg per day]), or placebo, twice per day for 28 days consecutively, followed by a minimum 14 day drug-free period. This cycle was repeated until disease progression or the patient became intolerant to the study treatment. Patients were stratified by site and presence or absence of extrahepatic metastasis or vascular invasion. The primary endpoint was overall survival, assessed in the full analysis set (ie, all patients who were treated with study drug except any individuals who were found not to have hepatocellular carcinoma or who were found to have active double cancer). Patients, medical staff, investigators, and the sponsor were masked to treatment assignment. Blinding was maintained even after study treatment concluded. This study is registered with JapicCTI, number JapicCTI-090920, and has been completed. Findings Between Oct 26, 2009, and Aug 22, 2012, we screened 399 patients. 65 patients were excluded due to not meeting criteria (n=61), declining to participate (n=3), or other reasons (n=1). 334 patients were randomly assigned to receive either S-1 (n=223) or placebo (n=111). One patient in the S-1 group did not receive treatment, and was thus excluded from analyses. At data cutoff, median follow-up was 32.4 months (IQR 24.0-34.7) in the S-1 group and 32.9 months (23.7-39.5) in the placebo group. Median overall survival was 11.1 months (95% CI 9.7-13.1) in the S-1 group and 11.2 months (9.2-12.8) in the placebo group (hazard ratio 0.86, 95% CI 0.67-1.10; p=0.20). The most frequently reported adverse events were skin hyperpigmentation (123 [55%] of 222 patients in the S-1 group vs nine [8%] of 111 patients in the placebo group), decreased appetite (104 [47%] vs 21 [19%]), fatigue (102 [46%] vs 20 [18%]), diarrhoea (77 [35%] vs 14 [13%]), and increased blood bilirubin (77 [35%] vs 14 [13%]). Serious adverse events were reported in 90 (41%) of 222 patients in the S-1 group and 24 (22%) of 111 patients in the placebo group. Five treatment-related deaths were reported in the S-1 group. Interpretation S-1 did not prolong overall survival in patients with sorafenib-refractory advanced hepatocellular carcinoma. Further research is needed to identify subgroups of patients who might benefit from S-1.