Study of Bepirovirsen in Participants Living With Human Immunodeficiency Virus and Chronic Hepatitis B Virus Infection (B-Focus)

This study will evaluate the efficacy and safety of bepirovirsen compared to placebo in participants with human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infection.

Inclusion Criteria: 1. Documented chronic hepatitis B virus (HBV) infection and documented human immunodeficiency virus (HIV)-1 infection greater than equal to (\>=) 12 months prior to Screening. 2. Must be on uninterrupted antiretroviral therapy (ART) containing at least tenofovir disoproxil (TDF) or tenofovir alafenamide (TAF) plus lamivudine (3TC) or emtricitabine (FTC) for greater than (\>)12 months, with no planned changes to the stable regimen over the duration of the study. o Switch in ART is permitted \>=6 months prior to Screening for reasons not related to loss of HIV or HBV control (e.g., change in formulary, tolerability, side effects). 3. Documented evidence of at least 2 plasma HIV-1 ribonucleic acid (RNA) measurements less than (\