A Study to Evaluate Sintilimab Plus Lenvatinib as Adjuvant Therapy in Hepatocellular Carcinoma With Portal Vein Tumor Thrombosis (PVTT) After Surgical Resection

Inclusion Criteria: * Subjects with a histopathological diagnosis of HCC * Undergone a curative resection * Pathologically confirmed HCC with portal vein tumor thrombus (PVTT) * Aged 18-75 years * No previous systematic treatment and locoregional therapy for HCC prior to randomization * No extrahepatic spread * Full recovery from Curative resection within 4 weeks prior to randomization * Child-Pugh: Grade A or B(7) * ECOG-PS score: 0 or 1 * Adequate organ function Exclusion Criteria: * Known fibrolamellar HCC, sarcomatoid HCC, mixed cholangiocarcinom or recurrent HCC * Any preoperative treatment for HCC including local and systemic therapy * Have received more than 1 cycle of adjuvant TACE following surgical resection * Any acute active infectious diseases, active or history of autoimmune disease, or immune deficiency * Known history of serious allergy to any monoclonal antibody or targeted anti-angiogenic drug * Subjects with inadequately controlled hypertension or history of hypertensive crisis or hypertensive encephalopathy * Active or history of autoimmune disease * Thrombosis or thromboembolic event within 6 months prior to the start of study treatment * Any persistent serious surgery-related complications; esophageal and/or gastric variceal bleeding within 6 months * Abdominal fistula, gastrointestinal perforation or intraperitoneal abscess within 6 months prior to the start of study treatment * Inability or refusal to comply with the treatment and monitoring