BRIEF—New COVID-19 sa-mRNA results from CSL and Arcturus vaccine

Australian biotech CSL Limited and US firm Arcturus Therapeutics today announced the results of a follow-up analysis of a Phase III study evaluating a booster dose of ARCT-154.

This is claimed to be the world's first approved self-amplifying messenger RNA (sa-mRNA) COVID-19 vaccine, compared to a conventional mRNA COVID-19 vaccine. ARCT-154 was administered at one-sixth the dose of Comirnaty (5μg versus 30μg, respectively).

The new analysis at six months post-vaccination shows that ARCT-154 induces a longer immune response as compared to Comirnaty for both the original Wuhan strain and Omicron BA.4/5 variant and an advantage in antibody persistence.

"These results further support sa-mRNA's differentiating attribute to provide prolonged protection against COVID-19 at lower doses," said Dr Jonathan Edelman, senior vice president, Vaccines Innovation Unit, CSL.

"This data, coupled with the initial Phase III results and approval in Japan late last year, show that this innovative vaccine technology has the potential to provide significant advancements over conventional mRNA vaccines including prolonged protection at lower doses," said Pad Chivukula, chief scientific officer of Arcturus.