Arcturus Therapeutics Holdings Inc. is an American RNA medicines biotechnology company focused on the discovery, development and commercialization of therapeutics for rare diseases and infectious diseases. Arcturus has developed proprietary lipid nanoparticle RNA therapeutics for nucleic acid medicines including small interfering RNA, messenger RNA, gene editing RNA, DNA, antisense oligonucleotides, and microRNA. The company develops RNA therapeutics for the treatment of rare diseases such as ornithine transcarbamylase deficiency, and respiratory diseases such as cystic fibrosis. As of 2021, vaccine medicines include a vaccine candidate for COVID-19 and an influenza vaccine in the preclinical development phase. The vaccine for COVID-19 was authorised in Japan in 2023 and the European Union in 2025. Wikipedia