Withdrawal of Therapy After Long-Term Antiviral Treatment for Chronic Hepatitis B

Chronic hepatitis B affects at least 1.5 million Americans and is a major cause of cirrhosis, end-stage liver disease and hepatocellular carcinoma. Five oral antiviral agents have been licensed for use in chronic hepatitis B in the United States. These agents are effective at suppressing viral replication, improving liver disease and reversing cirrhosis. The standard indications for starting antiviral therapy have been developed and widely accepted. Less clear is how long therapy should continue and when and under what conditions should therapy be stopped. Withdrawal after one year of therapy is commonly followed by relapse that in rare instances is severe and can be fatal. With longer courses of therapy, withdrawal of antiviral therapy has been associated with fewer and less severe relapses, but the criteria for stopping treatment are still unclear.

In this study, we propose to withdraw therapy in up to 50 patients with both HBeAg positive and negative chronic hepatitis B who have received a minimum of 4 years of oral nucleoside therapy with a serum HBV DNA level less than 500 IU/ml in the 6 months prior to withdrawal. After an outpatient evaluation, consenting patients will be withdrawn from therapy and followed carefully for presence of symptoms, abnormal liver tests and HBV DNA levels monthly for 6 months and every 3 months thereafter. Patients who relapse will be offered retreatment. Patients without relapse will be followed for at least four years after stopping therapy. The primary endpoint of the study will be the proportion of patients who maintain an HBV DNA < 1,000 IU/ml, and a serum ALT or AST<1.5 times the upper limit of normal one year off therapy. Secondary endpoints will be the proportion of patients who maintain HBeAg loss and clear HBsAg one year off therapy, the number of ALT or AST flares, predictors of maintained virological suppression and HBeAg negativity and the proportion of subjects who require re-initiation of therapy.

• INCLUSION CRITERIA:

Age greater than 18 years and older, male or female

HBsAg positive for greater than 6 months

For HBeAg positive subjects, HBeAg loss with or without anti-HBe with a minimum period of antiviral therapy for 48 weeks after HBeAg loss was first detected.

HBV DNA less than or equal to 500 IU/mL tested on at least 2 occasions over the last 6 months

Antiviral therapy for a minimum of 4 years

Baseline ALT or AST within the upper limit of normal.

Willing and able to provide written, informed consent.

Subjects must be eligible to enter protocol 07-DK-0207 or be willing to be treated by their local physician should relapse or a hepatitis flare occur.

Exclusion criteria

Presence of cirrhosis (Ishak fibrosis score 5 or 6) on any liver biopsy performed within the last 4 years. In the absence of a liver biopsy then any three of the following five variables: platelet count less than or equal to 100,000/mm(3), reversal of ALT/AST ratio, total bilirubin greater than 2.0 mg/dL, splenomegaly on ultrasound and presence of esophageal or gastric varices or portal hypertensive gastropathy on endoscopy

Any history of decompensated liver disease

Prior or current therapy with tenofovir or tenofovir plus emtricitabine

Renal insufficiency defined as a serum creatinine greater than 1.5 mg/dL or an estimated glomerular filtration rate less than or equal to 50 mls/minute using the Cockroft and Gault formula.

Anti-hepatitis C virus positivity

Anti-hepatitis D virus positivity

Anti-human immunodeficiency virus positivity