The present invention provides compositions comprising therapeutic nucleic acids such as siRNA that target Hepatitis B virus (HBV) gene expression, lipid particles comprising one or more (e.g., a combination) of the therapeutic nucleic acids, and methods of delivering and/or administering the lipid particles (e.g., for treating HBV infection and/or HDV infection in humans).本發明提供包含靶向B型肝炎病毒(HBV)基因表現之諸如siRNA之治療性核酸之組成物、包含該等治療性核酸中之一或多種(例如,組合)之脂質粒子,以及遞送及/或投與該等脂質粒子之方法(例如,用於治療人類之HBV感染及/或HDV感染)。