A Study of Different Combination Regimens Including JNJ-73763989 and/or JNJ-56136379 for the Treatment of Chronic Hepatitis B Virus Infection

The purpose of this study is to establish the dose-response relationship for antiviral activity of 3 dose levels of JNJ-73763989+nucleos(t)ide analog (NA) and to evaluate the efficacy of combination regimens of JNJ-73763989+NA (with and without JNJ-56136379) and of JNJ-56136379+NA.

Hepatitis B virus (HBV) is a small deoxyribonucleic acid virus that specifically infects the human liver. The acute phase of infection is either followed by an immune controlled state or progresses to chronic hepatitis B. The worldwide estimated prevalence of chronic HBV infection is about 292 million people affected. Hepatitis B surface antigen (HBsAg) seroclearance is currently considered to be associated with the most thorough suppression of HBV replication (termed functional cure). With current available NA treatment strategies, rate of HBsAg seroclearance remains very low (around 3 percent \[%\]) even under long-term treatment. Also, with the persistently high global prevalence of HBV-associated mortality, there is a medical need for more effective finite treatment options that lead to sustained HBsAg seroclearance. JNJ-73763989 is a liver-targeted antiviral therapeutic for subcutaneous injection designed to treat chronic HBV infection via ribonucleic acid interference mechanism. JNJ-56136379 is an orally administered capsid assembly modulator that is being developed for the treatment of chronic HBV infection. The aim of the study is to evaluate efficacy as measured by proportion of participants who completed 48-week study intervention and qualified for stopping NA treatment at Week 48. The study includes: Screening phase (4 weeks), Double-blind study intervention phase (from Day 1 up to Week 48), and Follow-up phase (48 weeks after end of investigational intervention with a maximum duration of 96 weeks). The duration of individual study participation will be between 100 and 150 weeks. Safety and tolerability (including adverse events \[AEs\] and Serious AEs, laboratory assessments, electrocardiogram \[ECG\], vital signs, physical examination), efficacy (including HBsAg seroclearance), and pharmacokinetics will be assessed throughout the study.