This is a Phase Ib study to evaluate the safety and efficacy of sintilimab combined with bevacizumab biosimilar in patients with potentially resectable intermediate hepatocellular carcinoma (HCC).

Inclusion Criteria:

1. Able to provide informed consent and willing to sign an approved consent form

2. Age 18-75, male and female

3. Potentially resectable Intermediate (CNLC-IIa and IIb) HCC with diagnosis confirmed by histology/cytology or clinically

4. No prior therapy for HCC

5. Child-Pugh: A

6. ECOG PS: 0-1

7. Expected survival ≥6 months

8. Measurable disease per RECIST1.1

9. Major organ functions meet the following requirements:

   no blood transfusion, no use of hematopoietic stimulators (including g-csf, gm-csf, EPO and TPO) and infusion of human albumin preparations within 14 days prior to screening: neutrophil absolute count ≥1.0×10^9/L;Platelet count ≥ 75×10^9/L;Hemoglobin ≥ 9 g/dL;Serum albumin ≥ 2.8 g/dL;Total serum bilirubin ≤2.0× upper limit of normal range (ULN);Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5 × ULN;Serum creatinine (Cr) ≤1.5×ULN or Cr clearance ≥30 mL/min (calculated by Cockcroft-Gault formula);International standardized ratio (INR) ≤1.5×ULN;

10. Women of childbearing age must undergo a blood pregnancy test within the first 3 days of randomization with negative results and agree to use a reliable and effective method of contraception during the trial and within 120 days of the last trial drug administration. Male patients whose partners are women of childbearing age must agree to use a reliable and effective method of contraception during the trial and within 120 days of the last trial drug administration.

Exclusion Criteria:

1. known as cholangiocarcinoma (ICC) or mixed hepatocellular carcinoma, sarcomatoid hepatocellular carcinoma, and hepatic fibrolamellar carcinoma.
2. History of organ transplantation or hepatic encephalopathy
3. Tumor accumulation range exceeds 70% of liver volume
4. Pleural fluid, ascites, and pericardial effusion with clinical symptoms requiring drainage
5. Any history of kidney disease or nephrotic syndrome
6. History of gastrointestinal (GI) perforation and/or fistula in the past 6 months;Severe (G3) varicose veins are known to be present on endoscopy within 3 months before the first dose ; history of thrombosis, bleeding diathesis, coagulopathy or significant vascular disease
7. Prior life-threatening blood loss or grade 3/4 gastrointestinal bleeding requiring blood infusion, endoscopic or surgical intervention within 3 months
8. Arterial and venous thromboembolic events in the past 6 months, including myocardial infarction, unstable angina, cerebrovascular accident or transient ischemic attack, pulmonary embolism, deep vein thrombosis or any other serious thromboembolism history.
9. Severe bleeding tendency or coagulopathy, or are receiving thrombolytic therapy
10. Long-term use of vitamin K antagonists (such as warfarin) or low-dose low-molecular-weight heparin (such as enoxaparin 40 mg/day) or heparin
11. Uncontrollable hypertension, systolic blood pressure> 140 mmHg or diastolic blood pressure> 90 mmHg after optimal medical treatment, history of hypertensive crisis or hypertensive encephalopathy
12. Symptomatic congestive heart failure (New York Heart Association Grade II-IV), symptomatic or poorly controlled arrhythmia, history of congenital long QT syndrome or QTc> 500ms corrected during screening
13. History of abdominal or tracheoesophageal fistula, gastrointestinal (GI) perforation, or intra-abdominal abscess within 6 months of initiation of study treatment
14. Had major surgical procedure within 4 weeks of initiation of study treatment
15. Past and current history of pulmonary fibrosis, interstitial pneumonia, pneumoconiosis, drug-related pneumonia, severely impaired lung function and other lung diseases
16. Had acute or chronic active hepatitis B or C infection. Hepatitis C virus (HCV) RNA>103 copies/ml; hepatitis B surface antigen (HbsAg) and anti-HCV antibody are positive at the same time; hepatitis B virus (HBV) DNA positive but has received antiviral treatment is allowed.
17. Had active tuberculosis (TB)
18. Had human immunodeficiency virus (HIV) infection (HIV 1/2 antibody positive), known syphilis infection
19. Had severe infections that are active or poorly clinically controlled.
20. Had active autoimmune disease
21. Have used immunosuppressive drugs within 4 weeks before the first dose
22. Received live attenuated vaccines within 4 weeks before the first dose or plan to receive live attenuated vaccines during the study period
23. Received Chinese medicine with anti-tumor indications, or received drugs with immunomodulatory effect within 2 weeks before the first administration
24. Received any anti-PD-1 antibody, anti-PD-L1/L2 antibody, anti-CTLA4 antibody, or other immunotherapy
25. Allergic to Sintilizumab, Bevacizumab preparations and excipients, or had severe allergic reactions to other monoclonal antibodies in the past
26. Received treatment from other clinical trials within 4 weeks before the first dose
27. Female patients who are pregnant or breastfeeding