Collectively, the efficacy of antiviral treatment to improve long-term clinical outcome in cirrhotic CHB patients with low-level viremia (HBV DNA <2,000 IU/mL) has not been thoroughly evaluated. Considering that cirrhotic CHB patients with low-level viremia have considerably high risk of developing HCC in the previous retrospective study, the benefits of long-term antiviral treatment in these patients need further investigation.

Treatment

1) This clinical trial is a multicenter, open label, single arm study in cirrhotic chronic hepatitis B patients with low-level viremia. 
2) A total of 200 subjects meeting eligibility criteria will be enrolled and assigned to Treatment Arm (A) and 400 subjects from matched historical cohort will be compared to Treatment Arm.
- Treatment Arm (A): 200 subjects, TAF 25mg once daily with food for 3 years
- Matched Historical Controls Arm (B): 400 subjects, patients who did not receive antiviral treatment during their follow-up period, and  were matched with the treatment group in a 1:2 ratio according to their baseline characteristics by propensity-score matching method
3) Treatment Arm is scheduled to be followed up to 3 years. 

Arm Label

Target Number of Participant

Arm Type

Arm Description

TAF 25mg once daily with food for 3 years

Gender

Age

Description

1) Willing and able to provide written informed consent prior to study entry
2) Age ≥30 years and ≤80 years at the time of screening
3) Chronic hepatitis B infection defined as HBsAg (+) or HBV DNA (+) for at least 6 months prior to the Screening visit, or medical records indication a chronic hepatitis B virus infection by meeting all of the following criteria at the time of screening.  (1) HBsAg (+), (2) HBV DNA (+), and (3) HBcAb IgM (-)
4) Either HBeAg (+) or HBeAg (-)
5) Serum HBV DNA levels ≥20 IU/mL and <2,000 IU/mL at the time of screening
6) Evidence of liver cirrhosis defined as meeting any of the following criteria:
- Radiological evidence of liver cirrhosis by ultrasound, CT, or MRI
- Platelet count <150,000 /mm3
- Presence of esophageal or gastric varices by endoscopy in 2 years before the timing of screening
- Clinically significant portal hypertension
- Fibroscan ≥12.0 kPa (if the test was done in 6 months before the time of screening)
7) Estimated creatinine clearance ≥30 ml/min (by calculation of creatinine clearance or using the CKD-EPI equation)
8) Ability to comply with all study requirements

1) Confirmed known co-infection with HCV, HIV, or HDV
2) Current alcohol (60g/day) or substance abuse judged by the investigator that will potentially interfere with subject compliance
3) Any history of, or current evidence of, clinical hepatic decompensation (e.g., ascites, encephalopathy, variceal hemorrhage, or Child-Pugh score of ≥8, with the exception of Gilbert syndrome) in 1 year before the time of screening
4) Currently on or have received therapy with Interferon or immunosuppressant (including systemic chemotherapy) within 12 months prior to the screening
5) Requirement for chronic use of systemic immunosuppressant including, but not limited to, corticosteroid (prednisone equivalent of >40 mg/day for >2 weeks), azathioprine, or monoclonal antibodies
6) Received solid organ or bone marrow transplant
7) History of severe, life-threatening or other significant sensitivity to any excipients of the study drugs
8) Any other clinical conditions (cardiovascular, respiratory, neurologic, or renal conditions) or prior therapy that, in the opinion of the investigator, would make the subject unsuitable for the study or unable to comply with dosing requirements.
9) Currently on or have received antiviral treatment for ≥ 2 weeks within 6 months prior to the screening
10) History or current evidence of hepatocellular carcinoma (HCC), or high α-fetoprotein (AFP) > 20 ng/mL. But, the patients with AFP > 20 ng/mL can be enrolled if AFP shows decreasing trend and there is no evidence of HCC by dynamic CT or MRI)
11) Malignancy other than hepatocellular carcinoma within the 5 years prior to screening, with the exception of specific cancers that are cured by surgical resection (within 2 years prior to screening with confirmation of no evidence of disease). Subjects under evaluation for possible malignancy are not eligible.
12) Concurrent enrollment in another clinical study for other type of antiviral treatment for CHB or immune modulatory drug within 3 months prior to randomization, participation to an observational (non-interventional) clinical studies or interventional studies not using anti-HBV or immune modulatory drugs, or during the follow-up period of an interventional study are not exclusion criteria.
13) Pregnant women, women who are breastfeeding or who believe they may wish to become pregnant during the course of the study

The primary efficacy endpoint of this study is the cumulative incidence rate of composite clinical events including hepatocellular carcinoma, death, liver transplantation, decompensated liver cirrhosis defined as Child-Pugh score ≥8, liver cirrhosis-related complications (e.g., development of ascites, hepatic encephalopathy, gastroesophageal varix bleeding, spontaneous bacterial peritonitis, hepatorenal syndrome, or sepsis), or liver-related unexpected hospital admission, in the full analysis set.

for 3 years

Cumulative incidence of composite clinical events

at year 1, 2, and 3

Cumulative incidence of hepatocellular carcinoma

at year 1, 2, and 3