Study of EYP001a to Assess Its Safety and Anti-viral Effect in CHB Patients in Combination With NA (ETV or TD)

A total of 49 eligible patients will be enrolled and randomized at approximately 14 study sites. Patients will be randomized prior to study drug (EYP001a or placebo and NA) administration on Day 1 in the ratio of 3:1 into 2 arms: * Experimental Arm: EYP001a Dose A QD + NA daily (37 patients) * Control Arm: Placebo + NA daily (12 patients) The maximum total engagement duration for eligible patients in this study is up to 370 days: 90 days screening, 112 days (16 weeks) treatment period and 168 days (24 weeks) follow-up. Patients enrolled in the study will be assessed as outpatients. Patient screening will occur no more than 90 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: 12 weeks (90 days) * 16 weeks treatment period: * Treatment Visit 1 (Week 1 \[Day 1\]) * Treatment Visit 2 (Week 2 \[Day 14 ±3 days\]) * Treatment Visit 3 (Week 4 \[Day 28 ±3 days\]) * Treatment Visit 4 (Week 6 \[Day 42 ±3 days\]) * Treatment Visit 5 (Week 8 \[Day 56 ±3 days\]) * Treatment Visit 6 (Week 10 \[Day 70 ± 3 days\]) * Treatment Visit 7 (Week 12 \[Day 84 ± 3 days\]) * Treatment Visit 8 (Week 14 \[Day 98 ± 3 days\]) * Treatment Visit 9 (Week 16 \[Day 112±3 days\]) * 24 weeks safety follow-up period: * Follow-up Visit 1 (Week 20 \[Day 140 ±7 days\]) * Follow-up Visit 2 (Week 28 \[Day 196 ±7 days\]) * Follow-up Visit 3 (Week 40 \[Day 280 ±7 days\]) Note: during follow-up patients are kept on NA until the end of the trial: Week 40 (consolidation Phase).