The Combination Therapy of Peginterferon Alfa-2a and Tenofovir versus Tenofovir Monotherapy in HBeAg-positive and HBeAg-negative Chronic Hepatitis B (HBRN Immune Active) study sought to compare the long-term efficacy of combination therapy with peginterferon plus tenofovir versus tenofovir monotherapy in the treatment of chronic hepatitis B. This randomized (1:1) parallel group trial compared (i) tenofovir disoproxil fumarate (TDF) 300 mg daily for 192 weeks (4 years) and (ii) peginterferon (PegIFN) alfa-2a 180 µg weekly for 24 weeks plus TDF 300 mg daily for 192 weeks (4 years). Enrolled participants were stratified by HBeAg status (positive/negative), genotype (A versus all others), and cirrhosis (present versus absent). After 192 weeks of treatment, participants meeting criteria for treatment discontinuation stopped treatment and were followed for 48 weeks (total duration of treatment and follow up was 240 weeks). Emtricitabine/tenofovir coformulated as Truvada, approved for treatment of HIV but not for treatment of hepatitis B virus (HBV) infection, was offered to patients with primary nonresponse, partial virological response, or confirmed virologic breakthrough.

The objectives of the study were to define the role of limited duration peginterferon alfa-2a in the presence of tenofovir in treating patients with chronic hepatitis B by:

• Comparing the long-term efficacy of initial treatment with combination therapy consisting of peginterferon alfa-2a plus TDF versus TDF monotherapy
• Evaluating “off treatment” sustained responses following combination therapy with peginterferon alfa-2a plus TDF versus TDF monotherapy

The primary outcome measure was the percent of participants with hepatitis B surface antigen (HBsAg) loss by week 240.

Inclusion criteria:

• Enrolled in the Hepatitis B Research Network (HBRN) Cohort Study or completed the necessary components of the cohort baseline evaluation by the end of the baseline visit for this study.
• At least 18 years of age at the time of randomization (day 0).
• Chronic HBV infection as evidenced by at least one of the following:
• HBsAg positive result within 8 weeks prior to randomization and another time at least 24 weeks prior to randomization with no HBsAg negative result in between.
• HBsAg positive plus absence of detectable anti-HBc IgM in serum within 8 weeks prior to randomization.
• HBsAg positive within 8 weeks prior to randomization and HBV DNA ≥ 1,000 IU/mL on 2 occasions at least 24 weeks apart (can include result from screening visit within 8 weeks of randomization).
• HBsAg positive within 8 weeks prior to randomization plus evidence of chronic hepatitis B infection as indicated by a liver biopsy within 144 weeks of randomization.
• HBeAg positive or negative.
• Serum HBV DNA ≥ 1000 IU/mL on 2 occasions at least 4 weeks apart within the 32 weeks prior to randomization (can include result from screening visit within 8 weeks of randomization).
• At least two elevated serum ALT levels (> 45 U/L for males and > 30 U/L for females) at least 4 weeks, and no more than 32 weeks apart with the second being within 8 weeks of randomization.
• Compensated liver disease, with total bilirubin ≤ 2 mg/dL (except if Gilbert’s syndrome), direct bilirubin ≤ 0.5 mg/dL, INR ≤ 1.5, and serum albumin ≥ 3.5 g/dL
• No evidence of hepatocellular carcinoma (HCC) based upon alpha-fetoprotein (AFP) ≤ 20 ng/mL within 8 weeks prior to randomization:
• Participants who meet AASLD criteria for HCC surveillance must have negative liver imaging by ultrasound (US), computerized tomography (CT), or magnetic resonance imaging (MR) within 28 weeks of randomization as part of standard of care.
• Participants with AFP > 20 ng/mL must be evaluated clinically with additional imaging and shown not to have HCC on CT or MRI.
• Liver biopsy that shows findings consistent with chronic hepatitis B with the modified Ishak histology activity index (HAI) ≥ 3 (necroinflammatory component only) or Ishak fibrosis score ≥ 1 or both, as assessed by the local consortium pathologist on review of a liver biopsy done within 144 weeks of randomization.
• Females of childbearing potential must agree to use an adequate method of contraception throughout the study and must have a negative pregnancy test immediately prior to the start of treatment.
• Provide informed consent and agree to adhere to the requirements of the study.

Exclusion criteria are documented in the study protocol.

Of 201 participants randomized to TDF+PegIFN (n=102) or TDF alone (n=99), 6 participants had lost HBsAg at the end of the treatment phase, 5 in the combination group, and 1 in the TDF alone group. By week 240, there were 9 participants that had cleared HBsAg, 5.3% in combination, and 4.1% in the monotherapy arm. HBsAg decline and loss occurred earlier with TDF+PegIFN than with TDF alone, with a ≥ 1-log IU/mL qHBsAg decline by week 24 in 28% in TDF+PegIFN compared with 6% in TDF alone. HBsAg loss occurred in 7 of 12 (58%) with hepatitis B virus subgenotype A2 (all HBeAg positive), compared with only 2 of 189 (1%) with other hepatitis B virus genotypes, and in 8 of 93 (8.6%) HBeAg positive versus 1 of 87 (1.1%) HBeAg negative. PegIFN combined TDF followed by protocolized TDF withdrawal led to earlier but not higher percentages of HBsAg clearance.