This is a multi centre, two parallel arm, randomized, open-label, Phase 2a experimental study of oral Farnesoid X Receptor (FXR) modulator EYP001a to assess its safety and anti-viral effect when administered to non-treated (treatment naive or off treatment) chronic Hepatitis B (CHB) patients in combination with entecavir (ETV) and pegylated interferon alpha2a (peg-IFN). An experimental treatment period of 16 weeks will be followed by a 24 week maintenance period with ETV standard of care (SoC).

In total 30 eligible patients will be enrolled and randomized at approximately 7 study sites.

Patients will be randomized prior to study drug (EYP001a, ETV and peg-IFN) administration on Day 1 in the ratio of 1:1 into 2 treatment arms:

• Arm 1: EYP001a QD + ETV 0.5 mg QD + peg-IFN dosed per body surface area (180 µg, 135 µg or 90 µg) QW (± 3 days) (15 patients)
• Arm 2: EYP001a QD + peg-IFN dosed per body surface area (180 µg, 135 µg or 90 µg) QW (± 3 days) (15 patients)

Patients enrolled in the study will be assessed as outpatients. Patient screening will occur no more than 37 days prior to the Day 1 visit. Eligible patients will undergo further assessments on Day 1 to qualify for study drug administration on Day 1.

The visits during the study are planned as below:

• Screening visit: 5 weeks (37 days)
• 16 weeks treatment period
• 24 weeks maintenance period. During maintenance period patients are kept on ETV until the end of the trial at Week 40.

Inclusion Criteria:

• Has given voluntary written informed consent before performance of any study related procedure.

• Are treatment naive or without HBV treatment for at least 60 days or 5 times the elimination half-life, whichever is longer.

• Patient has CHB:

  1. HBV DNA ≥ 20,000 IU/mL for HBeAg positive and ≥2'000 for HBeAg negative and
  2. HBsAg ≥ 2.5 log10 IU/mL.

• Has liver imaging to screen for hepatocellular carcinoma or concomitant pancreaticobiliary disease either in the prior 6 months or at screening.

• Patient is not of childbearing potential or, if of childbearing potential, is not pregnant as confirmed by a negative serum human chorionic gonadotropin test at screening and is not planning a pregnancy during the course of the study.

Exclusion Criteria:

• Is an employee of a clinical research organization, vendor, or Sponsor involved with this study.

• Has known hepatocellular carcinoma or pancreaticobiliary disease.

• Neutropenia (defined by two confirmed values during Screening period of < 1500/μL).

• Has Gilbert syndrome.

• Shows evidence of worsening liver tests, defined as either a confirmed (2 assessments at least 3 days apart) increase > 2 ULN ALT or AST or an increase of > 1.5 × baseline value of TBL or associated with clinical signs or symptoms of liver impairment.

• Has known or suspected non-CHB liver disease

• History of cirrhosis or liver decompensation, including ascites, hepatic encephalopathy, or presence of oesophageal varices.

• Probable or possible F4 stage with a vibration controlled transient elastography (VCTE) > 11.7 kPa leads to exclusion

• Has known history of alcohol abuse or daily heavy alcohol consumption

• Has any of the following exclusionary laboratory results at screening:

  1. ALT > 2 × ULN, AST > 2 × ULN
  2. INR > 1.2 × ULN, (normal range is 0.8 to 1.2)
  3. Platelet count < 100 G/L
  4. Estimated glomerular filtration rate < 50 mL/min/1.73m2 (the Modification of Diet in Renal Disease formula)
  5. Thyroid-stimulating hormone > 1.5 × ULN or abnormal free triiodothyronine or free thyroxine.