Nucleic acid drugs such as antisense oligonucleotides (ASO) and small interfering RNA (siRNA) can suppress the expression of disease-related genes in cells, enabling an approach to drug targets different from conventional drug modalities such as antibodies and small molecules. However, one of the major challenges in realizing nucleic acid drugs is their delivery to the desired organs [1]. Recently, several nucleic acid drugs for genetic diseases targeting the liver have been marketed and developed due to the progress of ligand-conjugated nucleic acid technology composed of N-acetylgalactosamine (GalNAc) and nucleic acids, which targets asialoglycoprotein receptors expressed on the surface of hepatocytes (GalNAc-oligonucleotides (ASO, siRNA): Fig. 124.1a).