Background: Sorafenib is the accepted first-line systemic therapy for HCC, but no standard option is available for patients with tumor progression following sorafenib. An open-label phase II study suggested that REG, a multikinase inhibitor, had an acceptable safety profile and showed evidence of antitumor activity in patients with progressive HCC (Bolondi et al. Eur J Cancer 2011; 47 [Suppl 1]: abstract 6.576): disease control was achieved in 26/36 patients (72%) and median time to progression (TTP) was 4.3 months; median overall survival (OS) was 13.8 months. On the basis of these promising data, a phase III trial was designed. Methods: This randomized, double-blind, placebo (PBO)-controlled, multinational study (ClinicalTrials.gov identifier NCT01774344) will assess the efficacy and tolerability of REG vs PBO in patients with HCC that has progressed following sorafenib treatment (target n=530). Inclusion criteria include Barcelona Clinic Liver Cancer stage B or C disease, Child–Pugh A liver function, and Eastern Cooperative Oncology Group performance status (ECOG PS) 0 or 1. Patients who discontinued sorafenib ≥8 weeks before study entry or who received other previous systemic therapy for HCC will be excluded. Patients will be randomized in a 2:1 ratio to receive REG 160 mg or matching PBO OD for weeks 1–3 of each 4-week cycle; all patients will also receive best supportive care. Treatment will continue until disease progression, death, intolerable toxicity, or patient/investigator decision to stop. Doses of study drug may be delayed or reduced to manage clinically significant drug-related toxicities. The primary endpoint is OS; secondary endpoints are TTP, progression-free survival, tumor response, and safety. Analysis will be according to randomized group, stratified by geographic region (Asia vs rest of world), ECOG PS (0 vs 1), alfa-fetoprotein level (<400 vs ≥400 ng/ml), extrahepatic disease (yes vs no), and macrovascular invasion (yes vs no). In addition, blood, plasma, and archival tissue will be assessed for pharmacokinetic and biomarker analyses, and health-related quality of life and health utility will be measured. Clinical trial information: NCT01774344.