Arcturus Therapeutics and CSL’ ARCT-154 shows superior immunogenicity

Arcturus Therapeutics (ARCT) and CSL (CSLLY) announced the publication in Lancet Infectious Diseases of a Phase 3 study showing that a booster dose of ARCT-154, a novel, self-amplifying messenger RNA vaccine, elicited a numerically higher immune response against the original Wuhan-Hu-1 virus strain, and a superior immune response against Omicron BA.4/5 subvariant of SARS-CoV-2 virus compared to a booster dose of the conventional mRNA vaccine Comirnaty. ARCT-154 results were achieved with one-sixth the dose of Comirnaty. Both vaccines were well-tolerated, with no causally associated severe or serious adverse events. The study was conducted in partnership with Meiji Seika Pharma, a global health company based in Japan. The phase 3 study results with ARCT-154 were used to support the approval of ARCT-154 for primary immunization and as a booster dose in Japan in November of this year. The ARCT-154 study is ongoing and will continue to collect safety data and assess durability of the immune response in participants at 3-, 6- and 12-months post-vaccination.